cssi/SciSciGPT-SciSciNet huggingface dataset:
The formation of supermassive black holes and the evolution of supermassive stars

The existence of supermassive black holes is supported by a growing body of observations. Supermassive black holes and their formation events are likely candidates for detection by proposed long-wavelength, space-based gravitational wave interferometers like LISA. However, the nature of the progenitors of supermassive black holes is rather uncertain. Supermassive black hole formation scenarios that involve either the stellar dynamical evolution of dense clusters or the hydrodynamical evolution of supermassive stars have been proposed. Each of these formation scenarios is reviewed and the evolution of supermassive stars is then examined in some detail. Supermassive stars that rotate uniformly during their secular cooling phase will spin up to the mass-shedding limit and eventually contract to the point of relativistic collapse. Supermassive stars that rotate differentially as they cool will probably encounter the dynamical bar mode instability prior to the onset of relativistic collapse. A supermassive star that undergoes this bar distortion, prior to or during collapse, may be a strong source of quasiperiodic, long-wavelength gravitational radiation.
Leaky waves and the production of sound by turbulent flow from an elastic nozzle

An analysis is made of the sound generated by axisymmetric multipole source distributions interacting with the open end of a coaxial nozzle modeled by a semi-infinite circular elastic duct. The influence of surface compliance is important at frequencies below the coincidence frequency ω c of bending waves on a plate of the same thickness as the duct wall. At frequencies between the ring frequency of the duct, ω R , and ω c , the intensity of the sound scattered from the open end is reduced relative to that produced by the same source when the duct is rigid. At lower frequencies, scattering is dominated by sound launched by leaky extensional waves of the duct, such that the intensity of the radiation exceeds that from a rigid duct by a factor of order 1(κ 0 a) 2 ≫1, where κ 0 and a are, respectively, the acoustic wavenumber and duct radius. The leaky waves propagate supersonically relative to the fluid and cause the radiation directivity to be sharply peaked in an upstream direction determined by the ratio of the sound speed in the fluid and the leaky wave phase velocity. Application of the theory is made to determine the axisymmetric component of the sound produced by low Mach number turbulent flow from the nozzle. Structural compliance would normally be expected to reduce the direct radiation produced by an adjacent turbulent flow, and this is confirmed in the present case at source frequencies between ω R and ω c . At lower frequencies, however, the effect is offset by the greater efficiency of leaky wave generation. The net result is that the overall acoustic spectral levels are similar to those for a rigid nozzle, but the directivity is significantly different. Subsonically propagating flexural waves are also generated at the nozzle with an efficiency which, in the case of a steel nozzle in water, exceeds that of sound production via the leaky waves by 30-40 dB at low frequencies. Their influence in the fluid decays rapidly with distance from the nozzle axis, but they may, in practice, make a significant contribution to the flow-generated sound if they are scattered at structural discontinuities upstream of the nozzle exit. The results are illustrated by numerical predictions for a steel nozzle in water. An appendix contains a derivation of a new formula for the sound power radiated by a leaky wave.
Terminally alkylated polyamine analogues as chemotherapeutic agents

which are found in significant amounts in nearly every prokaryotic and eukaryotic cell type. Despite the ubiquitous nature of these compounds, the precise roles that polyamines play in cellular physiology are still being defined, with new avenues for research arising continuously. As a result, there are active research programs focusing on polyamine metabolism in an extremely diverse set of disciplines. The pathways for polyamine metabolism have been elucidated for a relatively small number of organisms. There are important interspecies differences in polyamine metabolism, especially between eukaryotic cells, plants, and some bacteria and protozoa. In some prokaryotes, only putrescine and spermidine are synthesized, while in other cases, such as certain thermophilic bacteria, polyamines with chains longer than spermine are found. In some parasitic organisms, there are additional enzymes which are not present in the host cell and, as such, provide a target for the design of specific antiparasitic agents. However, the enzymes involved in human and mammalian polyamine metabolism are reasonably similar, and inhibitors targeted to these enzymes rely on the observation that polyamine metabolism is accelerated and polyamines are required in higher quantities, in target cell types. The diversity of biological research in the polyamine field is the subject of an excellent book by Seymour Cohen.1 This Perspective will deal with the use of polyamine analogues as chemotherapeutic agents, i.e., the use of synthetic polyamine analogues as anticancer or antiinfective agents. The reader should be aware of additional areas of polyamine research (polyamines as modulators of the NMDA receptor, polyamine-based venoms, polyamines as potential carriers for drug delivery, polyamines used in boron-neutron capture therapy, etc.) which are beyond the scope of this review. The polyamine pathway represents an important target for chemotherapeutic intervention, since depletion of polyamines results in the disruption of a variety * Address correspondence to: Patrick M. Woster, Ph.D, Dept. of Pharmaceutical Sciences, 539 Shapero Hall, Wayne State University, Detroit, MI 48202. Tel: 313-577-1523. Fax: 313-577-2033. E-mail: woster@wizard.pharm.wayne.edu. † Johns Hopkins Oncology Center. § Wayne State University. Figure 1. Structures of the natural polyamines: putrescine (1), spermidine (2), and spermine (3). © Copyright 2001 by the American Chemical Society
The Microjansky Radio Galaxy Population

We use highly spectroscopically complete observations of the radio sources from the VLA 1.4 GHz survey of the Hubble Deep Field-North region to study the faint radio galaxy population and its evolution. The fraction that can be optically spectroscopically identified is fairly independent of radio flux, with about 60%-80% identified at all fluxes. We spectrally classify the sources as absorbers, star formers, Seyfert galaxies, and broad-line AGNs, and we analyze their properties by type. We supplement the spectroscopic redshifts with photometric redshifts measured from the rest-frame ultraviolet to mid-infrared spectral energy distributions. Using deep X-ray observations of the field, we do not confirm the existence of an X-ray-radio correlation for star-forming galaxies. We also do not observe any correlations between 1.4 GHz flux and R magnitude or redshift. We find that the radio powers of the host galaxies rise dramatically with increasing redshift, while the optical properties show at most small changes. Assuming that the locally determined far-infrared-radio correlation holds at high redshifts, we estimate total FIR luminosities for the radio sources. We note that the FIR luminosity estimates for any radio-loud AGNs, which we conservatively do not try to remove from the sample, will be overestimates. Considering only the radio sources with quasar-like bolometric luminosities, we find a maximum ratio of candidate highly obscured AGNs to X-ray-luminous (L0.5-2 keV or L2-8 keV ≥ 1042 ergs s-1) sources of about 1.9. Finally, we use source-stacking analyses to measure the X-ray surface brightnesses of various populations. We find the contributions to the 4-8 keV light from our candidate highly obscured AGNs to be very small, and hence these sources are unable to account for the light that has been suggested may be missing at these energies.
Ethics, Finance, and Automation: A Preliminary Survey of Problems in High Frequency Trading

All of finance is now automated, most notably high frequency trading. This paper examines the ethical implications of this fact. As automation is an interdisciplinary endeavor, we argue that the interfaces between the respective disciplines can lead to conflicting ethical perspectives; we also argue that existing disciplinary standards do not pay enough attention to the ethical problems automation generates. Conflicting perspectives undermine the protection those who rely on trading should have. Ethics in finance can be expanded to include organizational and industry-wide responsibilities to external market participants and society. As a starting point, quality management techniques can provide a foundation for a new cross-disciplinary ethical standard in the age of automation.
On the Impossibility of Highly-Efficient Blockcipher-Based Hash Functions

Fix a small nonempty set of blockcipher keys . We say a blockcipher-based hash function is highly-efficient if it makes exactly one blockcipher call for each message block hashed, and all blockcipher calls use a key from . Although a few highly-efficient constructions have been proposed, no one has been able to prove their security. In this paper we prove, in the ideal-cipher model, that it is impossible to construct a highly-efficient iterated blockcipher-based hash function that is provably secure. Our result implies, in particular, that the Tweakable Chain Hash (TCH) construction suggested by Liskov, Rivest, and Wagner (Advances in CryptologyCRYPTO 02, Lecture Notes in Computer Science, vol. 2442, pp. 3146, Springer, Berlin, 2002) is not correct under an instantiation suggested for this construction, nor can TCH be correctly instantiated by any other efficient means.
A self-linking invariant of virtual knots

In this paper we introduce a new invariant of virtual knots and links that is non-trivial for many virtuals, but is trivial on classical knots and links. The invariant will initially be expressed in terms of a relative of the bracket polynomial [4], and then extracted from this polynomial in terms of its exponents, particularly for the case of knots. The analog of the bracket polynomial will be denoted {K} (with curly brackets) and called the binary bracket polynomial. See Section 3 for the definition and properties of the binary bracket. The key to the combinatorics of this invariant is an interpretation of the state sum in terms of 2-colorings of the associated diagrams.
Calculus and extensions of Arrow's theorem☆

Abstract A discrete analog for a calculus argument about mappings between spaces is developed. This discrete ‘calculus argument’ is used to characterize the ‘kinds of axioms’ that lead to conclusions similar to that of Arrow's Theorem. In this manner, new extensions of Arrow's Theorem are found. In addition, this approach is applied to certain economic allocation and welfare procedures, paradoxes from statistics and probability, the Hurwicz-Schmeidler result about Pareto optimal Nash equilibria, the Gibbard-Satterthwaite Theorem, Nakamura's Theorem about simple games, etc. A new, sharp class of ‘possibility theorems’ are derived that hold not only for transitive preferences, but also for utility functions, probability measures, etc.
Radiatively-induced Lorentz and CPT violating Chern–Simons term in QED

Abstract We calculate the induced Lorentz- and CPT-violating Chern–Simons term arising from the Lorentz- and CPT-violating sector of quantum electrodynamics with a b μ ψ γ μ γ 5 ψ term. The result to all orders in b coincides with the previous linear-in-b calulation by Chung and Oh [hep-th/9812132] as well as Jackiw and Kostelecký [Phys. Rev. Lett. 82 (1999) 3572], since all higher order terms vanish.
The Effect of Adhesive Curing Condition on Bonding Strength in Auto Body Assembly

The bonding strength of metal-to-metal lap joining of a two-part epoxy-based adhesive employed in an automotive assembly line was investigated under different heating rates (10 to 6000°C/min), peak temperatures (room to 250°C), and holding times. The results indicate that bonding strength is controlled mainly by the peak curing temperature and the heating rate. The maximum bonding strength appears between 70 and 110°C, but the value of it depends on the heating rate. At heating rates of 10, 50, and 100°C/min, the peak strength decreases with increasing heating rate. However, a further increase in heating rate to 2000-6000°C/min resulted in higher peak bonding strength. The microstructures and fractured surfaces after shear testing were examined by a scanning electron microscope. The results revealed that many gas bubbles (voids) were formed during the adhesive curing process, and the fracture process was controlled by the link of the voids. At low heating rates (10-100°C/min), the mean void size and volume fraction increase with heating rate and peak temperature, causing the weakening of the bonding strength. However, at very high heating rates (2000-6000°C/min), the rapid hardening of the adhesive suppressed the development of gas bubbles, so that the mean void size and volume fraction were low, and the bonding strength was high. This result indicates that to effectively improve the adhesive bonding strength, both the chemical reaction (degree of cure) and physical response (gas bubble formation) need to be optimized.
A Search for High-Velocity Be Stars

We present an analysis of the kinematics of Be stars based upon Hipparcos proper motions and published radial velocities. We find approximately 23 of the 344 stars in our sample have peculiar space motions greater than 40 km s-1 and up to 102 km s-1. We argue that these high-velocity stars are the result of either a supernova that disrupted a binary or ejection by close encounters of binaries in young clusters. Be stars spun up by binary mass transfer will appear as high-velocity objects if there was significant mass loss during the supernova explosion of the initially more massive star, but the generally moderate peculiar velocities of Be X-ray binaries indicate that the progenitors lose most of their mass prior to the supernova (in accordance with model predictions). Binary formation models for Be stars predict that most systems bypass the supernova stage (and do not receive runaway velocities) to create ultimately Be + white dwarf binaries. The fraction of Be stars spun up by binary mass transfer remains unknown, since the post-mass transfer companions are difficult to detect.
A Comprehensive Analysis of Uncertainties Affecting the Stellar Mass - Halo Mass Relation for 0<z<4

We conduct a comprehensive analysis of the relationship between central galaxies and their host dark matter halos, as characterized by the stellar mass-halo mass (SM-HM) relation, with rigorous consideration of uncertainties. Our analysis focuses on results from the abundance matching technique, which assumes that every dark matter halo or subhalo above a specific mass threshold hosts one galaxy. We provide a robust estimate of the SM-HM relation for 0 < z < 1 and discuss the quantitative effects of uncertainties in observed galaxy stellar mass functions (including stellar mass estimates and counting uncertainties), halo mass functions (including cosmology and uncertainties from substructure), and the abundance matching technique used to link galaxies to halos (including scatter in this connection). Our analysis results in a robust estimate of the SM-HM relation and its evolution from z = 0 to z = 4. The shape and the evolution are well constrained for z < 1. The largest uncertainties at these redshifts are due to stellar mass estimates (0.25 dex uncertainty in normalization); however, failure to account for scatter in stellar masses at fixed halo mass can lead to errors of similar magnitude in the SM-HM relation for central galaxies in massive halos. We also investigate the SM-HM relation to z = 4, although the shape of the relation at higher redshifts remains fairly unconstrained when uncertainties are taken into account. We find that the integrated star formation at a given halo mass peaks at 10%-20% of available baryons for all redshifts from 0 to 4. This peak occurs at a halo mass of 7 × 1011 M ☉ at z = 0 and this mass increases by a factor of 5 to z = 4. At lower and higher masses, star formation is substantially less efficient, with stellar mass scaling as M * ~ M 2.3 h at low masses and M * ~ M 0.29 h at high masses. The typical stellar mass for halos with mass less than 1012 M ☉ has increased by 0.3-0.45 dex for halos since z ~ 1. These results will provide a powerful tool to inform galaxy evolution models.
Thermal and hadrochemical equilibration in nucleus-nucleus collisions at the SPS

Abstract The currently available set of hadron abundances at the SPS for central S + Au(W,Pb) collisions is compared to predictions from a scenario assuming local thermal and hadrochemical equilibrium. The data are consistent with a freeze-out temperature T = 160–170 MeV. Spectra are consistent with this temperature range and a moderate transverse expansion. The freeze-out points at the AGS and SPS are found to be close to the phase boundary between a hadron gas and an ideal quark-gluon phase.
Single-Frequency LCR Databridge Impedance Measurements as Surrogate Measures for the Integrity of Human Skin

While LCR databridge instruments are used to probe the integrity of skin, there is confusion in this literature about what these instruments report in series (SER) or parallel (PAR) modes at user-specified measurement frequencies, typically 100 or 1,000 Hz. Here, the theoretical meanings of resistance and capacitance measurements in PAR and SER mode are presented. A large body of data from human cadaver skin are used to show that LCR databridge resistance measured at 100 Hz in PAR mode and capacitance measured at 100 Hz in SER mode are most sensitive to skin resistivity, which is the electrical measurement most closely related to skin integrity. The single-frequency databridge resistance values are shown to correlate to skin permeability measurements using tritiated water.
Algorithms for Solving Dynamic Models with Occasionally Binding Constraints

Abstract We describe and compare several algorithms for approximating the solution to a model in which inequality constraints occasionally bind. Their performance is evaluated and compared using various parameterizations of the one sector growth model with irreversible investment. We develop parameterized expectation algorithms which, on the basis of speed, accuracy and convenience of implementation, appear to dominate the other algorithms.
Phosphine Mediated Conjugation of S-Nitrosothiols and Aldehydes.

S-Nitrosothiols (SNO) and their biological implications as an important post-translational modification are under active investigation. In our work on bioorthogonal reactions of protein SNO we have uncovered the chemistry of this functionality that shows synthetic promise. Herein we report a phosphine-mediated reaction between SNO and aldehydes to form thioimines. A simple synthesis of benzoisothiazole based on this reaction is presented.
Ultrafast coherent dynamics of optically inactive excitons in semiconductors

The center-of-mass momentum distribution of optically created excitons in semiconductors is known to be constrained by the (very small) light momenta at times immediately following the excitation, and it is governed by incoherent scattering processes on longer time scales. The present theoretical analysis suggests that, on intermediate time scales, nonlinear mean-field interactions between excitons lead to a coherent, wave-like evolution in the momentum distribution of optically inactive excitons. Proposals for possible experimental verification of these predictions are discussed.
The Recognition of Extraterrestrial Intelligence

A necessary but not sufficient condition for the recognition of extraterrestrial intelligence is a significant departure from thermodynamic equilibrium. This can be discerned clearly in the inverse problem of the detection of terrestrial intelligence from a distance. Photography of the Earth in reflected sunlight reveals no clear sign of life until 100 m resolution is achieved, at which point the agricultural and urban reworking of the Earth9s surface in rectangular arrays first becomes obvious. This pattern is however detectable only over interplanetary distances. Mars exhibits no such patterns. The departure from radiative equilibrium - represented by radio, television and radar technology - in the microwave spectrum of the Earth is by contrast easily detectable over interstellar distances. Even with a technology no more advanced than our own, a civilization on a planet of a nearby star could easily determine, by auto-correlation techniques, the artificiality of these radio signals. Intentional interstellar radio messages should be detected and decrypted far more readily. Possible message contents for interstellar discourse of a modulated signal at any accessible frequency include (1) m-dimensional imagery represented by the transmission of numbers which are the products of m prime numbers; and (2) the use of a common mathematics, physics or astronomy to convey a range of information on more difficult subjects. The only direct attempts to date to communicate with extraterrestrial intelligence - the plaques aboard the Pioneer 10 and 11 spacecraft - are discussed briefly.
Hyperaccretion during Tidal Disruption Events: Weakly Bound Debris Envelopes and Jets

After the destruction of the star during a tidal disruption event (TDE), the cataclysmic encounter between a star and the supermassive black hole (SMBH) of a galaxy, approximately half of the original stellar debris falls back onto the hole at a rate that can initially exceed the Eddington limit by orders of magnitude. We argue that the angular momentum of this matter is too low to allow it to attain a disk-like configuration with accretion proceeding at a mildly super-Eddington rate, the excess energy being carried away by a combination of radiative losses and radially distributed winds. Instead, we propose that the infalling gas traps accretion energy until it inflates into a weakly bound, quasi-spherical structure with gas extending nearly to the poles. We study the structure and evolution of such "zero-Bernoulli accretion" flows as a model for the super-Eddington phase of TDEs. We argue that such flows cannot stop extremely super-Eddington accretion from occurring, and that once the envelope is maximally inflated, any excess accretion energy escapes through the poles in the form of powerful jets. We compare the predictions of our model to Swift J1644+57, the putative super-Eddington TDE, and show that it can qualitatively reproduce some of its observed features. Similar models, including self-gravity, could be applicable to gamma-ray bursts from collapsars and the growth of SMBH seeds inside quasi-stars.
No primordial magnetic field from domain walls

Abstract It is pointed out that, contrary to some claims in the literature, the domain walls cannot be a source of a correlated at large scales primordial magnetic field, even if the fermionic modes bound on the wall had ferromagnetic properties. In a particular model with massive (2+1)-dimensional fermions bound to a domain wall, previously claimed to exhibit a ferromagnetic behavior, it is explicitly shown that the fermionic system in fact has properties of a normal diamagnetic with the susceptibility vanishing at high temperature.
NPOESS Precipitation Retrievals Using the ATMS Passive Microwave Spectrometer

This letter evaluates the ability of the U.S. National Polar-orbiting Operational Environmental Satellite System 22-channel Advanced Technology Microwave Sounder (ATMS) to retrieve surface precipitation rates (millimeters per hour); water path estimates for rain, snow, and graupel (millimeters); and peak vertical wind (convective strength, meters per second). Simulated retrieval accuracies for ATMS were compared to those for its predecessor the Advanced Microwave Sounding Unit (AMSU), both of which sample the 23- to 190-GHz spectrum. ATMS retrieves all precipitation parameters up to ~ 25% more accurately than AMSU except for cloud ice and snow water paths, which are comparable. Image sharpening of the ATMS Nyquist-sampled observations below 90 GHz further improves the recovery of small features but amplifies noise so that the benefits are restricted primarily to finely structured convective systems.
Relative Permeability From Unsteady-State Displacements With Capillary Pressure Included

A semianalytic method for calculation of relative permeabilities from unsteady-state displacement data is developed. The method is based on the simultaneous solution of the fractional-flow equation and an integro-differential equation, derived from the material-balance and Darcy equations for immiscible displacement of two incompressible phases, including the capillary pressure by use of various volumetric relationships. This method for calculating two-phase relative permeabilities from unsteady-state displacement data is not restricted to the high-flow-rate experimental conditions used to overcome capillary and effects. Removal of this restriction allows the analysis of low-permeability cores with water and oil where the flow rates are low and capillary end effects are important. Our method allows direct calculation from the experimental data without intermediate interpretations of graphs.
Detection of cervical neoplasia: reducing the risk of error.

In cytology studies false negative smears range from 1.8% to 20% due to different levels of cytologic expertise and of material presented to the pathologist. Only 6% of in situ carcinomas of the cervix have an abnormal gross appearance so routine multiple biopsies are needed. Schillers test using a weak aqueous solution of iodine leaves an area of carcinoma unstained but colors normal cervical epithelium a dark brown. However not all areas which fail to stain represent foci of cancer. Multiple biopsies and endocervical curettage are required particularly to detect lesions not involving the portio. Conization is the most accurate method for evaluating the suspicious cervix. 80 histo logic sections should be examined from each cervix specimen. Complicati ons of conization may be hemorrhage cervical stenosis uterine perforation and pelvic infection. Only after 4-6 weeks does pelvic infection cease to be a significant risk. When done during pregnancy conization may cause a fetal loss of 15%. Colposcopy has a low false-negative rate but cannot detect lesions inside the cervical canal. It is the best method of clinical evaluation of patients with abnormal cytological smears particularly during pregnancy. A colposcopic diagnosis is based on an evaluation of vascular pattern intercapillary distance surface contour color tone and clarity of demarcation. Where colposcopic examination is unsatisfactory and cytology is positive conization is indicated. The final diagnosis depends on the histology of the directed biopsy.
A measure of control for secondary cytokine-induced injury of articular cartilage: A computational study

In previous works, the author and collaborators establish a mathematical model for injury response in articular cartilage. In this paper we use mathematical software and computational techniques, applied to an existing model to explore in more detail how the behavior of cartilage cells is influenced by several of, what are believed to be, the most significant mechanisms underlying cartilage injury response at the cellular level. We introduce a control parameter, the radius of attenuation, and present some new simulations that shed light on how inflammation associated with cartilage injuries impacts the metabolic activity of cartilage cells. The details presented in the work can help to elucidate targets for more effective therapies in the preventative treatment of post-traumatic osteoarthritis.
Designing efficient synthetic routes to polyfunctionality

Benzotriazole-mediated methodology was successfully applied for the preparation of many classes of polyfunctional organic compounds.
Mesino oscillation in MFV SUSY

R-parity violating supersymmetry in a Minimal Flavor Violation paradigm can produce same-sign dilepton signals via direct sbottom-LSP pair production. Such signals arise when the sbottom hadronizes and the resulting mesino oscillates into an antimesino. The first bounds on the sbottom mass are placed in this scenario using current LHC results.
Umpolung of Michael Acceptors Catalyzed by N-Heterocyclic Carbenes

N-Heterocyclic carbenes can catalyze beta-alkylations of a range of alpha,beta-unsaturated esters, amides, and nitriles that bear pendant leaving groups to form a variety of ring sizes. In this process, the nucleophilic catalyst transiently transforms the normally electrophilic beta carbon into a nucleophilic site through an unanticipated addition-tautomerization sequence.
DENSITY ANOMALIES IN THIN LIQUID FILMS OF HYDRIDE FUNCTIONAL SILOXANES

Thin liquid films of polyfunctional poly(methylhydro-dimethyl)siloxane copolymers (PMDMS) have been investigated using X-ray reflectivity. The electron density of liquids within the films is altered significantly as a function of film thickness and fraction of Si-H groups in the PMDMS molecule. The density profile in the region next to the Si substrate is highly sensitive to the interaction between the liquid molecules and the substrate surface. Increasing the number of Si-H groups interacting with the surface leads to a more pronounced low-density region in the vicinity of the substrate. However, one-dimensional ordering normal to the surface is identical for all PMDMS films.
IDEA Requirements for Children with Disabilities in Faith-Based Schools: Implications for Practice

Although public schools have both the obligation and ability to provide free and appropriate public education (FAPE) for all children and youth with disabilities enrolled in public schools, their obligation does not end there. Children with disabilities enrolled by their parents in private schools do have certain rights to services under the Individuals with Disabilities Education Act (IDEA), and it is expected that public schools will engage in meaningful consultation with private school officials and parents to ensure that those rights are met. In that light, this article summarizes specific requirements of IDEA for students enrolled in private schools, with an emphasis on those students enrolled in faith-based schools, and changes introduced in IDEA 2004. Although it is clear that the extent to which IDEA does apply to children in private schools is limited, there are clear implications for the amount of federal flow-through funds that are available for the provision of special education services to th...
A study of the anisotropy associated with dipole asymmetry in heavy ion collisions

The anisotropy associated with the initial dipole asymmetry in heavy ion collisions is studied via the two-particle relative azimuthal angle (?? = ?a ? ?b) correlations, within a multi-phase transport model. For a broad selection of centrality, transverse momenta () and pseudorapidity (?a, b), a fitting method is used to decompose the anisotropy into a rapidity-even component, characterized by the Fourier coefficient v1, and a global momentum conservation component. The extracted v1 values are negative for pT ? 0.7?0.9?GeV, reach a maximum at 2?3 GeV, and decrease at higher pT. The v1 values vary weakly with ? and centrality, but increase with collision energy and the parton cross-section. The extracted global momentum conservation component is found to depend on ?? = ?a ? ?b for |??| < 3.
Organic Metals and Semiconductors: The Chemistry of Polyacetylene, (CH)x, and Its Derivatives.

Both cis- and trans-forms of polyacetylene, (CH)x, may be prepared as silvery, flexible, polycrystalline, semiconducting films. The cis-films can be stretched to over three times their original length with partial alignment of the (CH)x. fibrils. Through chemical or electrochemical doping, the electrical conductivity of the films can be increased over twelve orders of magnitude with properties ranging from insulator (σ 103 ohm-1cm-1). By the use of donors or acceptors, n-type or p-type polymer, respectively, is produced. Photoelectro-chemical photovoltaic cells have been fabricated using (CH)x as the active photoelectrode. For example, using a sodium polysulfide solution as an electrolyte, Voc ∼0.3 volts and Isc ∼40 ∼ amps/cm2 were obtained under an illumination of ca. 1 sun.
Joint demosaicing and denoising

The output image of a digital camera is subject to a severe degradation due to noise in the image sensor. This paper proposes a novel technique to combine demosaicing and denoising procedures systematically into a single operation by exploiting their obvious similarities. We first design a filter as if we are optimally estimating a pixel value from a noisy single-color (sensor) image. With additional constraints, we show that the same filter coefficients are appropriate for color filter array interpolation (demosaicing) given noisy sensor data. The proposed technique can combine many existing denoising algorithms with the demosaicing operation. In this paper, a total least squares denoising method is used to demonstrate the concept. The algorithm is tested on color images with pseudorandom noise and on raw sensor data from a real CMOS digital camera that we calibrated. The experimental results confirm that the proposed method suppresses noise (CMOS/CCD image sensor noise model) while effectively interpolating the missing pixel components, demonstrating a significant improvement in image quality when compared to treating demosaicing and denoising problems independently
Dysregulation of temperature and liver cytokine gene expression in immunodeficient wasted mice

Wasted mice bear the spontaneous autosomal recessive mutation wst/wst; this genotype is associated with weight loss beginning at 21 days of age, neurologic dysfunction, immunodeficiency at mucosal sites, and increased sensitivity to the killing effects of ionizing radiation. The pathology underlying the disease symptoms is unknown. Experiments reported here were designed to examine thermoregulation and liver expression of specific cytokines in wasted mice and in littermate and parental controls. Our experiments found that wasted mice begin to show a drop in body temperature at 21-23 days following birth, continuing until death at the age of 28 days. Concomitant with that, livers from wasted mice expressed increased amounts of mRNAs specific for cytokines IL,6 and IL-1, the acute phase reactant C-reactive protein, c-jun, and apoptosis-associated Rp-8 when compared to littermate and parental control animals. Levels of {beta}-transforming growth factor (TGF), c-fos, proliferating cell nuclear antigen (PCNA), and ornithine amino transferase (OAT) transcripts were the same in livers from wasted mice and controls. These results suggest a relationship between an acute phase reactant response in wasted mice and temperature dysregulation.
A factorization of the Conway polynomial

It is shown that the Conway polynomial of a link is a product of two factors, the first of which is the Conway polynomial of a knot obtained by banding together the link components and the second is determined, via an explicit formula, by the \(\tilde\mu\)-invariants of the link. In particular we get a formula, in terms of the μ-invariants, for the first non-zero coefficient of the Conway polynomial. A similar formula is obtained for the multi-variable Alexander-polynomial.
Scheduling in time-correlated wireless networks with imperfect CSI and stringent constraint

In a wireless network, the efficiency of scheduling algorithms over time-varying channels depends heavily on the accuracy of the Channel State Information (CSI), which is usually quite “costly” in terms of consuming network resources. Scheduling in such systems is also subject to stringent constraints such as power and bandwidth, which limit the maximum number of simultaneous transmissions. In the meanwhile, communication channels in wireless systems typically fluctuate in a time-correlated manner. We hence design schedulers to exploit the temporal-correlation inherent in channels with memory and Automatic Repeat reQuest (ARQ) feedback from the users for better channel state knowledge, under the assumption of Markovian channels and the stringent constraint on the maximum number of simultaneously active users. We model this problem under the framework of a Partially Observable Markov Decision Processes. In recent work, a low-complexity optimal solution was developed for this problem under a long-term time-average resource constraint. However, in real systems with instantaneous resource constraints, how to optimally exploit the temporal correlation and satisfy realistic stringent constraint on the instantaneous service remains elusive. In this work, we incorporate a stringent constraint on the simultaneously scheduled users and propose a low-complexity scheduling algorithm that dynamically implements user scheduling and dummy packet broadcasting. We show that the throughput region of the optimal policy under the long-term average resource constraint can be asymptotically achieved in the stringent constrained scenario by the proposed algorithm, in the many users limiting regime.
Social creativity as a function of agent cognition and network properties: A computer model ☆

Abstract Inventions – concepts, devices, procedures – are often created by networks of interacting agents in which the agents can be individuals (as in a scientific discipline) or they can themselves be collectives (as in firms interacting in a market). Different collectives create and invent at different rates. It is plausible that the rate of invention is jointly determined by properties of the agents (e.g., their cognitive capacity) and by properties of the network of interactions (e.g., the density of the communication links), but little is known about such two-level interactions. We present an agent-based model of social creativity in which the individual agent captures key features of the human cognitive architecture derived from cognitive psychology, and the interactions are modeled by agents exchanging partial results of their symbolic processing of task information. We investigated the effect of agent and network properties on rates of invention and diffusion in the network via systematic parameter variations. Simulation runs show, among other results, that (a) the simulation exhibits network effects, i.e., the model captures the beneficial effect of collaboration; (b) the density of connections produces diminishing returns in term of the benefits on the invention rate; and (c) limits on the cognitive capacity of the individual agents have the counterintuitive consequence of focusing their efforts. Limitations and relations to other computer simulation models of creative collectives are discussed.
The W51 Giant Molecular Cloud

We present 45''–47'' angular resolution maps at 50'' sampling of the 12CO and 13CO J = 1–0 emission toward a 139 × 133 region in the W51 H II region complex. These data permit the spatial and kinematic separation of several spectral features observed along the line of sight to W51 and establish the presence of a massive (1.2 × 106 M⊙), large (Δl × Δb = 83 × 114 pc) giant molecular cloud (GMC), defined as the W51 GMC and centered at (l, b, V)c ≈ (495, -02, 61 km s-1). A second massive (1.9 × 105M⊙), elongated (22 × 136 pc) molecular cloud is found at velocities of ~68 km s-1 along the southern edge of the W51 GMC. Of the five radio continuum sources that classically define the W51 region, the brightest source at λ6 cm (G49.5-0.4) is spatially and kinematically coincident with the W51 GMC and three (G48.9-0.3, G49.1-0.4, and G49.2-0.4) are associated with the 68 km s-1 cloud. Published absorption-line spectra indicate that the fifth prominent continuum source (G49.4-0.3) is located behind the W51 molecular cloud. The W51 GMC is among the upper 1% of clouds in the Galactic disk by size and the upper 5%–10% by mass. While the W51 GMC is larger and more massive than any nearby molecular cloud, the average H2 column density is not unusual given its size, and the mean H2 volume density is comparable to that in nearby clouds. The W51 GMC is also similar to other clouds in that most of the molecular mass is contained in a diffuse envelope that is not currently forming massive stars. We speculate that much of the massive star formation activity in this region has resulted from a collision between the 68 km s-1 cloud and the W51 GMC.
The weighted hook-length formula II: Complementary formulas

Recently, a new weighted generalization of the branching rule for the hook lengths, equivalent to the hook formula, was proved. In this paper, we generalize the complementary branching rule, which can be used to prove Burnside's formula. We present three different proofs: bijective, via weighted hook walks, and via the ordinary weighted branching rule.
Land Grabs Today: Feeding the Disassembling of National Territory

This essay focuses on the larger assemblage of elements that promoted and facilitated the sharp increase in foreign land acquisitions by governments and firms since 2006. The concern is not to document the empirics of foreign land acquisition. Conceptually the essay negotiates between the specifics of the current phase of land acquisitions, on the one hand, and, on the other, the assemblage of practices, norms, and shifting jurisdictions within which those acquisitions take place. This assemblage of diverse elements does not present itself explicitly as governance. But I argue it is a type of governance embedded in larger structural processes shaping our global modernity; in fact, it may have had deeper effects on the current phase of land acquisitions than some of the explicit governance instruments for regulating land acquisitions. This mode of analysis is based on the conceptual and methodological work I developed in my book, Territory, Authority, Rights (Sassen, 2008); put succinctly it proposes that ...
Frothy Housing Markets and Local Stock-Price Movements

Prior empirical research finds habitat effects manifest in stock pricing among firms that share headquarters cities. We empirically investigate whether trends in residential real estate prices affect headquarters-city stock pricing phenomena for companies across U.S. metro areas for 1989–2004. Specifically, we hypothesize that stocks of firms headquartered in ‘hot’ residential real estate markets experience higher returns compared to stocks of firms from ‘cold’ markets. We also hypothesize that stocks of firms headquartered in hot real estate markets display stronger return comovement with same-city stocks. We find support for these hypotheses during the 1999–2004 sample period which coincides with the start of the housing bubble of the 2000 s; we find mixed results in earlier periods. Our findings indicate that city-specific home price patterns conditionally affect stock pricing of local firms, suggesting that investor behavior is influenced by localized shocks to household real estate wealth.
Crater saturation and equilibrium: A Monte Carlo simulation

Conditions of crater saturation and equilibrium have been simulated with a Monte Carlo computer program which utilizes a generating function of the form N = b x D to the -a. The following conclusions have been deduced from the results of the model: (1) saturation and equilibrium for large craters occur at crater densities substantially greater than those observed on the moon, Mars, and Mercury, an indication that the observed populations are essentially production populations, (2) generating functions with a greater than 2 lead to final crater populations with a = 2, (3) generating functions with a between 2 and 1.5 lead to crater populations with the parameter a approaching 1.0, and (4) changes in the slope of crater populations occur gradually and over a wide interval of crater densities and diameters as saturation is approached.
The origin of biological homochirality

The single handedness of biological molecules has fascinated scientists and laymen alike since Pasteur's first painstaking separation of the enantiomorphic crystals of a tartrate salt over 150 years ago. More recently, a number of theoretical and experimental investigations have helped to delineate models for how one enantiomer might have come to dominate over the other from what presumably was a racemic prebiotic world. Mechanisms for enantioenrichment that include either chemical or physical processes, or a combination of both, are discussed in the context of experimental studies in autocatalysis and in the phase behaviour of chiral molecules.
Concept and Laboratory Analysis of Trajectory-Based Automation for Separation Assurance

An operating concept and a laboratory analysis methodology were developed and tested to examine how four-dimensional trajectory analysis methods could support higher levels of automation for separation assurance in the National Airspace System. Real-time simulations were conducted in which a human controller generated conflict resolution trajectories using an automated trial planning resolution function, but only in response to conflicts detected and displayed by an automatic conflict detection function. Objective metrics were developed to compare aircraft separation characteristics and flying time efficiency under automated operations to that of today’s operations using common airspace and traffic scenarios. Simulations were based on recorded air traffic data from Fort Worth and Cleveland Centers and conducted using today’s and nearly two-times today’s traffic levels. Results suggest that a single controller using trajectory-based automation and data link communication of control clearances to aircraft could manage substantially more traffic than they do now with improved route efficiency while maintaining separation. The simulation and analysis capability provides a basis for further analysis of semi-automated, or fully automated, separation assurance concepts.
The Stability and Prospects of the Detection of Terrestrial/Habitable Planets in Multiplanet and Multiple Star Systems

Given the tendency of planets to form in multiples, and the observational evidence in support of the existence of potential planet-hosting stars in binaries or clusters, it is expected that extrasolar terrestrial planets are more likely to be found in multiple body systems. This paper discusses the prospects of the detection of terrestrial/habitable planets in multibody systems by presenting the results of a study of the long-term stability of these objects in systems with multiple giant planets (particularly those in eccentric and/or in mean-motion resonant orbits), systems with close-in Jupiter-like bodies, and systems of binary stars. The results of simulations show that while short-period terrestrial-class objects that are captured in near mean-motion resonances with migrating giant planets are potentially detectable via transit photometry or the measurement of the variations of the transit-timing due to their close-in Jovian-mass planetary companions, the prospect of the detection of habitable planets with the radial velocity technique is higher in systems with multiple giant planets outside the habitable zone and binary systems with moderately separated stellar companions.