cssi/SciSciGPT-SciSciNet huggingface dataset:
A Unified Jet Model of X-Ray Flashes, X-Ray-rich Gamma-Ray Bursts, and Gamma-Ray Bursts. I. Power-Law-shaped Universal and Top-Hat-shaped Variable Opening Angle Jet Models

HETE-2 has provided strong evidence that the properties of X-ray flashes (XRFs), X-ray-rich gamma-ray bursts (GRBs), and GRBs form a continuum, and therefore that these three kinds of bursts are the same phenomenon. A key feature found by HETE-2 is that the density of bursts is roughly constant per logarithmic interval in burst fluence SE and observed spectral peak energy E, and in isotropic-equivalent energy Eiso and spectral peak energy Epeak in the rest frame of the burst. In this paper, we explore a unified jet model of all three kinds of bursts, using population synthesis simulations of the bursts and detailed modeling of the instruments that detect them. We show that both a variable jet opening angle model in which the emissivity is a constant independent of the angle relative to the jet axis and a universal jet model in which the emissivity is a power-law function of the angle relative to the jet axis can explain the observed properties of GRBs reasonably well. However, if one tries to account for the properties of XRFs, X-ray-rich GRBs, and GRBs in a unified picture, the extra degree of freedom available in the variable jet opening angle model enables it to explain the observations reasonably well while the power-law universal jet model cannot. The variable jet opening angle model of XRFs, X-ray-rich GRBs, and GRBs implies that the energy Eγ radiated in gamma rays is ~100 times less than has been thought. The model also implies that most GRBs have very small jet opening angles (~half a degree). This suggests that magnetic fields may play an important role in GRB jets. It also implies that there are ~104-105 more bursts with very small jet opening angles for every burst that is observable. If this is the case, the rate of GRBs could be comparable to the rate of Type Ic core-collapse supernovae. These results show that XRFs may provide unique information about the structure of GRB jets, the rate of GRBs, and the nature of Type Ic supernovae.
Exercise training by individuals with predialysis renal failure: Cardiorespiratory endurance, hypertension, and renal function

The purpose of this study was to determine the effects of 4 months of exercise training (ET) on cardiorespiratory function and endurance, blood pressure, muscle strength, hematology, blood lipids, and renal function in individuals with chronic renal failure (CRF) who were not yet on dialysis. Sixteen subjects were recruited to volunteer for participation in this study, but only eight completed all study phases. Subjects were first evaluated before and after a 2-month baseline (BL1 and BL2), after 4 months of ET, and again after 2 months of detraining (DT). ET did not change hematology, blood lipids, or echocardiographic measurements of left ventricular function and mass. Resting systolic and diastolic blood pressures decreased significantly from BL after the ET (146 +/- 15.7/87 +/- 9 mm Hg to 124 +/- 17.5/78 +/- 9.5 mm Hg; P < 0.02), and then increased significantly after DT (139 +/- 14.7 mm Hg and 87 +/- 9.9 mm Hg; P < 0.01). Peak oxygen consumption (pVO2) changed significantly during the study (1.3 +/- 0.3 L/min, 1.5 +/- 0.3 L/min, and 1.4 +/- 0.3 L/min for BL2, ET, and DT, respectively; P < 0.02), as did the VO2 at the ventilatory threshold (0.65 +/- 0.18 L/min, 0.92 +/- 0.19 L/min, and 0.68 +/- 0.23 L/min for BL2, ET, and DT, respectively; P < 0.01). Knee flexion peak torque increased after ET (43.4 +/- 25.6 Nm to 51.0 +/- 30.5 Nm; P < 0.02). GFR, as measured by creatinine clearance, continued to deteriorate during the course of the study (25.3 +/- 12.0 mL/min, 21.8 +/- 13.2 mL/min, and 21.8 +/- 13.2 mL/min for BL2, ET, and DT, respectively; P < 0.001). Individuals with predialysis CRF who undergo ET improve in functional aerobic capacity, muscular strength, and blood pressure.
Electric field control of ferromagnetism using multi-ferroics: the bismuth ferrite story.

Since the re-emergence of multi-ferroics and magnetoelectrics almost a decade ago, bismuth ferrite has been among the most heavily studied model system. It is a multi-ferroic with robust ferroelect...
Fast X-ray Transients and Gamma-ray Bursts: Constraints on Beaming

The detection of X-ray afterglows of γ-ray burst (GRB) sources has enabled the optical discovery that GRBs are at cosmological distances, which confirms that the enormous luminosities required must produce a relativistically expanding fireball. It is not yet clear whether this expansion is quasi-spherical or beamed, or if the beaming differs between the prompt GRB and afterglow, although the differences for both source emission and population models are profound. We show that relative beaming (prompt vs. afterglow) may be constrained by analysis of the "fast transient" X-ray sources cataloged by Pye & McHardy from the Ariel 5 survey as well as several other surveys (e.g., HEAO 1 experiments A-1/A-2). After removing contamination from likely stellar transients, and scaling from X-ray/γ-ray fluence ratios recently derived from Ginga and BeppoSAX, approximately half of the sources were possible prompt emission or afterglows from GRBs with γ-ray fluence of 1.2 × 10−5 ergs cm−2. Since the rate of these candidate afterglow events, 0.15 day−1, is consistent with the BATSE log N-log S distribution, no difference in prompt versus afterglow beaming is required. However, more sensitive X-ray monitors or hard X-ray imaging surveys, with better temporal and spatial resolution, could provide strong constraints on GRBs and beaming.
Efficacy of single-dose and conventional amoxicillin therapy in urinary-tract infection localized by the antibody-coated bacteria technic.

Abstract Urine specimens from 61 women with symptoms of cystitis who were infected with amoxicillin-sensitive organisms were examined by the antibody-coated bacteria assay. Patients with negative assays were randomized to receive either a single 3-g oral dose of amoxicillin or 10 days of amoxicillin, 250 mg, given by mouth four times per day (conventional therapy). Patients with positive assays received conventional therapy. All 43 patients without antibody-coated bacteria in the urine, 22 given single-dose therapy and 21 treated conventionally, were cured of their infection. Of 18 patients with antibody-coated bacteria, nine relapsed within one week of completion of conventional therapy. The results of the antibody-coated bacteria assay appear to predict the therapeutic response: both single-dose and conventional amoxicillin therapy are completely successful in patients with negative assays; in contrast, conventional therapy is ineffective in 50 per cent of patients with positive assays. (N Engl J Med 29...
Numerical simulation of heat transfer in simultaneously developing flows in parallel rectangular ducts

Abstract The F correction factor charts and the e–NTU relations assume the overall heat transfer coefficient to be constant across the heat exchanger. In microchannel heat exchangers, the short lengths and the comparatively thick walls through which heat is conducted preclude the existence of thermally fully developed flow over a large portion of the heat exchanger. In this study, a parallel flow heat exchanger is numerically simulated to determine the impact of different parameters on the performance and the accuracy of constant heat transfer coefficient assumption. It is shown that there is significant change in the overall heat transfer coefficient in the developing region and that the three-dimensional heat transfer in the heat exchanger wall must be included in the analysis.
Synthetic strategies to acetogenins. The hydroxybutenolide terminus

Abstract Oxygen may be introduced to either carbon of 2-allylbutenolides, allowing a simple terminal alkene to be the structural precursor of the hydroxybutenolide tail of acetogenins via ruthenium and osmium catalyzed reactions.
UNIFIED THEORY OF THE INTERPLANETARY MAGNETIC FIELD.

A simple model is used to present a unified picture of the polarity pattern of the interplanetary magnetic field observed during the solar cycle. Emphasis in this paper is on the field near solar maximum. The heliographic latitude dependence of the dominant polarity of the interplanetary magnetic field is explained in terms of weak poloidal (dipolar) field sources in the sun's photosphere. Unlike the Babcock theory, the author hypothesizes that the dipolar field exists at equatorial latitudes (0–20°), too, (as well as in polar regions) and that the major source of the interplanetary magnetic field observed near the ecliptic plane is the dipolar field from equatorial latitudes. The polarity of the interplanetary field data taken in 1968 and in the first half of 1969 near solar maximum may possibly be explained in terms of a depression of the dipolar field boundary in space. The effect on the solar wind of the greater activity in the northern hemisphere of the sun that existed in 1968 and in the first half of 1969 is believed responsible for this hypothesized depression, especially near solar maximum, of the plane separating the + and - dipolar polarity below the solar equatorial plane in space. Predictions are made concerning the interplanetary field to be observed near the ecliptic plane in each portion of the next solar cycle.
Anomalous Foam-Fractional-Flow Solutions at High-Injection Foam Quality

A thorough understanding of foam fundamentals is crucial to the optimal design of foams for improved oil recovery (IOR) or enhanced oil recovery (EOR). This study, for the first time, presents anomalous foam-fractional-flow solutions that deviate significantly from the conventional solutions at high-injection foam qualities by comparing method-of-characteristics and mechanistic bubble-population-balance simulations. The results from modeling and simulations derived from core-flood experiments revealed the following: There are three regions-Region A with relatively wet (or high f(w)) injection conditions in which the solutions are consistent with the conventional fractional-flow theory; Region C with very dry (or low f(w)) injection conditions in which the solutions deviate significantly; and Region B in between, which has a negative df(w)/dS(w) slope showing physically unstable solutions. For dry-injection conditions in Region C, the solutions require a constant state (IJ) between initial (I) and injection (J) conditions, forcing a shock from I to IJ by intersecting fractional-flow curves, followed by spreading waves or another shock to reach from IJ to J. The location of IJ in f(w) vs. S-w domain moves to the left (or toward lower SW) as the total injection velocity increases for both weak and strong foams until it reaches limiting water saturation. Even though foams at high-injection quality are popular for mobility control associating a minimum amount of surfactant solutions, foam behaviors at dry conditions have not been thoroughly investigated and understood. The outcome of this study is believed to be helpful to the successful planning of foam IOR/EOR field applications.
Average Number of Distinct Part Sizes in a Random Carlitz Composition

A composition of an integer n is called Carlitz if adjacent parts are different. Several characteristics of random Carlitz compositions have been studied recently by Knopfmacher and Prodinger. We will complement their work by establishing asymptotics of the average number of distinct part sizes in a random Carlitz composition.
Form-factors of pion and kaon

The form factors of pion and kaon are studied by an effective chiral theory of large NC QCD. Besides the vector meson poles an additional intrinsic form factors are found. Theory agrees well with data in both time-like and space-like regions. There is no adjustable parameter.
Vanadium Oxide-Carbon Nanotube Composite Electrodes for Use in Secondary Lithium Batteries

Abstract : Single-wall carbon nanotubes were used to form the electronically conducting network in lithium intercalation electrodes that incorporated vanadium oxide aerogels as the active material. Sol-gel methods were developed which integrated the nanotubes with V2O5 aerogel synthesis. The similarities in morphology and dimensional scale for the nanotubes and V2O5 ribbons enabled excellent electrical contact to be made between the two phases without seriously affecting the aerogel nanostructure. Intimate contact was established between the two phases at the nanodimensional level while the high pore volume of the aerogel provided electrolyte access throughout the composite material. The electrodes exhibited specific capacities in excess of 400 mAh/g at high discharge rates and retained this level of capacity on cycling.
Osmium tetroxide-promoted catalytic oxidative cleavage of olefins: an organometallic ozonolysis.

A mild, organometallic alternative to ozonolysis utilizing oxone and OsO4 is presented. This is a direct oxidation of olefins via the carbon−carbon cleavage of an osmate ester by the action of oxone. Twenty-four different olefins were converted to their corresponding ketones or carboxylic acids in high yields (>80%). Free alcohols, acetate- and benzyl-protected alcohols, and 1,2-diols were stable under these conditions. This method should be applicable for traditional organic synthesis.
Effects of Embedded Vortices on Injectant From Film Cooling Holes With Large Spanwise Spacing and Compound Angle Orientations in a Turbulent Boundary Layer

Experimental results are presented that describe the effects of embedded, longitudinal vortices on heat transfer and film injectant downstream of a single row of film cooling holes with compound angle orientations. Holes are spaced 7.8 hole diameters apart in the spanwise direction so that information is obtained on the interactions between the vortices and the injectant from a single hole. The compound angle holes are oriented so that their angles with respect to the test surface are 30 deg in a spanwise/normal plane projection, and 35 deg in a streamwise/normal plane projection. A blowing ratio of 0.5 is employed and the ratio of vortex core diameter to hole diameter is 1.6-1.67 just downstream of the injection holes (x/d = 10.2). At the same location, vortex circulation magnitudes range from O.15 m 2 /s to 0.18 m 2 /s
The management of anticoagulants in the periendoscopic period for patients with atrial fibrillation: a decision analysis

PURPOSE: The management of patients who undergo endoscopy while being treated with warfarin is challenging. We used decision analysis to determine the preferred strategy to manage anticoagulants in the periendoscopic period. METHODS: We designed a Markov model to estimate costs and quality-adjusted survival during a 10-year period in patients with nonvalvular atrial fibrillation undergoing screening colonoscopy. We compared six alternatives to the continue-warfarin strategy, which was to perform colonoscopy while the patient was taking full-dose warfarin. The hold-warfarin strategy was to stop warfarin 5 days before the colonoscopy. The repeat endoscopy strategy was to continue warfarin for a diagnostic colonoscopy, followed by a repeat procedure after cessation of warfarin if polypectomy was required. The dose-reduction strategy was to reduce the warfarin dose before colonoscopy. The low molecular weight heparin strategy was to administer subcutaneous low molecular weight heparin for 2 days before and 2 days after colonoscopy. The unfractionated heparin strategy was to administer intravenous unfractionated heparin for 2 days before and 2 days after the procedure. The vitamin K strategy was to hold warfarin for 4 days and to administer vitamin K if the international normalized ratio (INR) exceeded 2.0 the day before the procedure, or low molecular weight heparin if the INR was less than 1.5. RESULTS: For screening colonoscopy, assuming that polyps would be removed in 35% of examinations, the hold-warfarin and dose-reduction arms were both cost-effective strategies. The hold-warfarin arm was most cost-effective if the likelihood of polypectomy exceeded 60%, or if there was a low risk of stroke despite atrial fibrillation. The continue-warfarin strategy was preferred if the probability of polypectomy was 1% or less. CONCLUSION: Temporary warfarin cessation or halving the warfarin dose for several days before endoscopy was the preferred strategy for most patients. Periendoscopic heparin therapy was not cost-effective for patients with nonvalvular atrial fibrillation.
Approximation of k-dimensional maps☆

Abstract In this paper we prove the equivalence of the questions of Pasynkov [Dokl. Akad. Nauk SSSR 221 (1975) 543] and Uspenskij [Topology Appl. 85 (1998) 351]. We also get some partial results answering these questions in affirmative. As a corollary to these results we get an extention of the Hurewicz formula to the extensional dimension.
Cryosurgery in the treatment of giant cell tumors of bone. A report of 52 consecutive cases

Cryosurgery combined with routine "second look" biopsy has been previously reported in our initial series of 25 cases and has been demonstrated to be a promising modality in the treatment of giant cell tumors of bone. Further refinement of this surgical technique by more careful preliminary curettage has now significantly improved the rate of local tumor control and has markedly reduced the incidence of associated complications. While the problems of infection, fracture, delayed bone healing and local tumor recurrence have not been completely eliminated, our experience with 27 additional cases shows that it has been possible to develop a highly reliable procedure for the eradication of tumor while usually preserving joint motion and avoiding arthrodesis or amputation. The 1.9% malignancy rate is much lower than the previously reported papers by Hutter and Jaffe.
Natural resources and national security

(1975). Natural resources and national security. The Adelphi Papers: Vol. 15, The Middle East and the International System. Part II: Security and the Energy Crisis Papers from the IISS 16th Annual Conference, pp. 8-16.
Facile one-step synthesis of 2,5-diketopiperazines

Abstract We report a one-step protocol for the general synthesis of 2,5-diketopiperazines from an Fmoc-protected amino acid and an amino acid ester. The application of the method is highlighted by rapid and efficient preparation of various 2,5-diketopiperazines.
The Non-Linear Theory of Free Electron Lasers and Efficiency Enhancement

The development of lasers in which the active medium is a relativistic stream of free electrons has recently evoked much interest. The potential advantages of such free-electron lasers include, among other things, continuous frequency tunability, very high operating power, and high efficiency. The free-electron laser (FEL) is characterized by a pump field, for example, a spatially periodic magnetic field which scatters from a relativistic-electron beam. The scattered radiation has a wavelength much smaller than the pump wavelength, depending on the electron-beam energy. The authors present a general self-consistent nonlinear theory of the FEL process. The nonlinear formulation of the temporal steady-state FEL problem results in a set of coupled differential equations governing the spatial evolution of the amplitudes and wavelength of the radiation and space-charge fields. These equations are readily solved numerically since the amplitude and wavelength vary on a spatial scale which is comparable to a growth length of the output radiation. A number of numerical and analytical illustrations are presented, ranging from the optical to the submillimeter-wavelength regime. Our nonlinear formulation in the linear regime is compared with linear theory, and agreement is found to be excellent. Analytical expressions for the saturated efficiency and radiation amplitude are alsomore » shown to be in very good agreement with our nonlinear numerical solutions. Efficiency curves are obtained for both the optical and submillimeter FEL examples with fixed magnetic-pump parameters. It is shown that these intrinsic efficiencies can be greatly enhanced by appropriately contouring the magnetic-pump period. In the case of the optical FEL, the theoretical single-pass efficiency can be made greater than 20% by appropriately decreasing the pump period and increasing the pump magnetic field.« less
Black hole condensation and the web of Calabi-Yau manifolds

We review recent work concerning topology changing phase transitions through black hole condensation in Type II string theory. We then also briefly describe a present study aimed at extending the known web of interconnections between Calabi-Yau manifolds. We show, for instance, that all 7555 Calabi-Yau hypersurfaces in weighted projective four space are mathematically connected by extremal transitions.
Theoretical study of potential ultralow-noise confined-state photodetectors

A review of the basic issues implicit in the design of confined state photodetectors is presented. The basic device structure of a confined state photomultiplier consists of repeated unit cells each comprised of a narrow-gap semiconductor layer sandwiched between barrier layers of wider band-gap material. Gain in these structures is derived through carrier multiplication via impact excitation of confined electrons out of the narrow-gap semiconductor layer. Different device designs are considered in an attempt to maximize the device gain at minimum dark current. In some implementations, the barrier layers are chosen to be graded such that the leading edge discontinuity is at least twice that at the trailing edge of the well forming an asymmetric well design. We find that an asymmetric well design offers a much higher impact excitation of electrons confined within the well at a lower operating voltage than a symmetric well design, however, at the expense of increased dark current. Quantum versus classical confinement of the electrons within the well is also investigated. Though the ionization rate within the classical confinement design is less under comparable conditions to that in the quantum confinement design, the dark current is much less within the classical structure than in the quantum structure, giving a higher excitation-rate-to-dark-current ratio. The gain and dark current are investigated in structures made from GaN/AlGaN, HgTe/HgCdTe, and GaAs/AlGaAs.
Limited incision forehead lift for eyebrow elevation to enhance upper blepharoplasty.

Treatment of eyebrow ptosis to enhance the cosmetic effect from blepharoplasty is commonly done with a forehead lift using a coronal incision approach. The coronal scalp incision is associated with the annoying sequelae of frontoparietal scalp numbness, itching, and paresthesias, all of which can be permanent. A forehead lift technique with temporal scalp incisions only 4.5 to 5.0 cm in length can produce a result comparable with that of the coronal incision approach when combined with transpalpebral resection of the corrugator supercilii muscles and transection of the procerus muscle. This eyebrow elevation technique, like the endoscopic approach, minimizes the risk of permanently injuring the supraorbital nerve branches that innervate the frontoparietal scalp. Unlike the approach using only endoscopy, however, this technique can effectively treat cases of advanced eyebrow ptosis. The appropriate area of eyelid skin for excision may be difficult to assess when a forehead lift and upper blepharoplasty are done concomitantly. The described forehead lift incorporates a method to determine this area. This forehead lift technique, combined with a technique for protecting against overresecting upper eyelid skin, is described as used effectively on 140 blepharoplasty cases followed for 3 months to 4 years.
Random multi-overlap structures for optimization problems

We extend to the K-SAT and p-XOR-SAT optimization problems the results recently achieved, by introducing the concept of random multi-overlap structure, for the Viana-Bray model of diluted mean field spin glass. More precisely we can prove a generalized bound and an extended variational principle for the free energy per site in the thermodynamic limit. Moreover a trial function implementing ultrametric breaking of replica symmetry is exhibited. The ultrametric structure exhibits the same factorization property as the optimal structures for the Viana-Bray model and the Sherrington-Kirkpatrick nondiluted model.
Periodic boundary conditions for long-time nonequilibrium molecular dynamics simulations of incompressible flows

This work presents a generalization of the Kraynik-Reinelt (KR) boundary conditions for nonequilibrium molecular dynamics simulations. In the simulation of steady, homogeneous flows with periodic boundary conditions, the simulation box deforms with the flow, and it is possible for image particles to become arbitrarily close, causing a breakdown in the simulation. The KR boundary conditions avoid this problem for planar elongational flow and general planar mixed flow [T. A. Hunt, S. Bernardi, and B. D. Todd, J. Chem. Phys. 133, 154116 (2010)] through careful choice of the initial simulation box and by periodically remapping the simulation box in a way that conserves image locations. In this work, the ideas are extended to a large class of three-dimensional flows by using multiple remappings for the simulation box. The simulation box geometry is no longer time-periodic (which was shown to be impossible for uniaxial and biaxial stretching flows in the original work by Kraynik and Reinelt [Int. J. Multiphase Flow 18, 1045 (1992)]. The presented algorithm applies to all flows with nondefective flow matrices, and in particular, to uniaxial and biaxial flows.
The Mass of the Centaurus A Group of Galaxies

The mass M and the radius Rh of the Centaurus A group are estimated from the positions and radial velocities of 30 probable cluster members. For an assumed distance of 3.9 Mpc, it is found that Rh ~ 640 kpc. The velocity dispersion in the Cen A group is 114 ± 21 km s-1. From this value and Rh = 640 kpc, the virial theorem yields a total mass of 1.4 × 1013 M⊙ for the Cen A group. The projected mass method gives a mass of 1.8 × 1013 M⊙. These values suggest that the Cen A group is about 7 times as massive as the Local Group. The Cen A mass-to-light ratio is found to be M/LB = 155–200 (M/L)⊙. The cluster has a zero-velocity radius R0 = 2.3 Mpc.
The B. and M. Shapiro conjecture in real algebraic geometry and the Bethe ansatz

We prove the B. and M. Shapiro conjecture that if the Wronskian of a set of polynomials has real roots only, then the complex span of this set of polynomials has a basis consisting of polynomials with real coefficients. This, in particular, implies the following result: If all ramification points of a parametrized rational curve φ: ℂℙ 1 → ℂℙ r lie on a circle in the Riemann sphere ℂℙ 1 , then φ maps this circle into a suitable real subspace ℝℙ r ⊂ ℂℙ r . The proof is based on the Bethe ansatz method in the Gaudin model. The key observation is that a symmetric linear operator on a Euclidean space has real spectrum. In Appendix A, we discuss properties of differential operators associated with Bethe vectors in the Gaudin model. In particular, we prove a statement, which may be useful in complex algebraic geometry; it claims that certain Schubert cycles in a Grassmannian intersect transversally if the spectrum of the corresponding Gaudin Hamiltonians is simple. In Appendix B, we formulate a conjecture on reality of orbits of critical points of master functions and prove this conjecture for master functions associated with Lie algebras of types A r , B r and C r .
Enantiospecific, selective cyclooxygenase-2 inhibitors

Abstract Cyclooxygenase inhibition studies with novel indomethacin alkanolamides demonstrate the potential for dramatic differences in inhibitor properties conferred by subtle structural modifications. The transformation of non-selective α-(S)-substituted indomethacin ethanolamides to potent, COX-2 selective inhibitors by simple stereocenter inversion highlights this property.
REIONIZATION AND THE ABUNDANCE OF GALACTIC SATELLITES

One of the main challenges facing standard hierarchical structure formation models is that the predicted abundance of Galactic subhalos with circular velocities vc ~ 10-30 km s-1 is an order of magnitude higher than the number of satellites actually observed within the Local Group. Using a simple model for the formation and evolution of dark halos, based on the extended Press-Schechter formalism and tested against N-body results, we show that the theoretical predictions can be reconciled with observations if gas accretion in low-mass halos is suppressed after the epoch of reionization. In this picture, the observed dwarf satellites correspond to the small fraction of halos that accreted substantial amounts of gas before reionization. The photoionization mechanism naturally explains why the discrepancy between predicted halos and observed satellites sets in at vc ~ 30 km s-1, and for reasonable choices of the reionization redshift (zre ~ 5-12) the model can reproduce both the amplitude and shape of the observed velocity function of galactic satellites. If this explanation is correct, then typical bright galaxy halos contain many low-mass dark matter subhalos. These might be detectable through their gravitational lensing effects, through their influence on stellar disks, or as dwarf satellites with very high mass-to-light ratios. This model also predicts a diffuse stellar component produced by large numbers of tidally disrupted dwarfs, perhaps sufficient to account for most of the Milky Way's stellar halo.
Target capture and target ghosts

Optimal detection methods for small targets rely on whitened matched filters, which convolve the measured data with the signal model, and whiten the result with the noise covariance. In real-world implementations of such filters, the noise covariance must be estimated from the data, and the resulting covariance estimate may be corrupted by presence of the target. The resulting loss in SNR is called 'target capture'. Target capture is often thought to be a problem only for bright targets. This presentation shows that target capture also arises for dim targets, leading to an SNR loss which is independent of target strength and depends on the averaging method used to estimate the noise covariance. This loss is due to a 'coherent beat' between the true noise and that portion of the estimated noise covariance due to the target. This beat leads to 'ghost targets', which diminish the target SNR by producing a negative target ghost at the target's position. A quantitative estimate of this effect will be given, and shown to agree with numerical results. The effect of averaging on SNR is also discussed for data scenes with synthetic injected targets, in cases where the noise covariance is estimated using 'no target' data. For these cases, it is shown that the so-called 'optimal' filter, which uses the true noise covariance, is actually worse than a 'sub-optimal' filter which estimates the noise from scene. This apparent contradiction is resolved by showing that the optimal filter is best if the same filter is used for many scenes, but is outperformed by a filter adapted to a specific scene.
On the dispensability of public randomization in discounted repeated games

Abstract We show that any feasible, individually rational payoffs of an infinitely repeated game can arise as subgame perfect equilibrium payoffs if the discount factor is close enough to one even if mixed strategies are not observable and public randomizations are not available.
Conjugate addition of organocopper reagents in dichloromethane to α,β-unsaturated esters

Abstract Organocopper reagents in conjunction with Lewis acid activators provide greater stability than traditional cuprate reagents while maintaining the reactivity needed for conjugate addition reactions in dichloromethane. Whereas cuprates engage in cross-coupling pathways, organocopper nucleophiles are more selective for conjugate addition. The utility of organocopper reagents in dichloromethane for the conjugate addition to α,β-unsaturated esters is expanded upon herein.
HIGH ENERGY PARTICLES FROM THE UNIVERSE

It is an exciting time to be working at the interface between physics and astronomy. Experiments built to detect astrophysical and atmospheric sources of neutrinos, such as Super-Kamiokande , are providing what may be the first definitive evidence for neutrino mass. Cosmology experiments, such as those measuring the redshifts of type Ia supernovae and those determining the anisotropy of the microwave background, may have an important impact on particle physics as they confront our general view of the origin of the Universe. There have been similarly exciting developments at the high energy frontier of astronomy. Among other things:
Deposition of Electrochromic Tungsten Oxide Thin Films by Plasma‐Enhanced Chemical Vapor Deposition

Use of plasma-enhanced chemical vapor deposition (PECVD) for electrochromic WO{sub 3} film deposition is investigated. Oxygen, hydrogen, and tungsten hexafluoride were used as source gases. Reactant gas flow was investigated to determine the effect on film characteristics. High quality optical films were obtained at deposition rates on the order of 100 {angstrom}/s. Higher deposition rates were attainable but film quality and optical coherence degraded. Atomic emission spectroscopy (AES), was used to provide an in situ assessment of the plasma deposition chemistry. Through AES, it is shown that the hydrogen gas flow is essential to the deposition of the WO{sub 3} film. Oxygen gas flow and tungsten hexafluoride gas flow must be approximately equal for high quality films.
Clinical implementation of a new HDR brachytherapy device for partial breast irradiation.

Abstract Purpose To present the clinical implementation of a new HDR device for partial breast irradiation, the Strut-Adjusted Volume Implant (SAVI), at the University of California, San Diego. Methods and materials The SAVI device has multiple peripheral struts that can be differentially loaded with the HDR source. Planning criteria used for evaluation of the treatment plans included the following dose volume histogram (DVH) criteria: V90 >90%, V150 Results SAVI has been used on 20 patients to date at UC San Diego. In each case, the dose was modulated according to patient-specific anatomy to cover the tumor bed, while sparing normal tissues. The dosimetric data show that we can achieve greater than 90% coverage with respect to V90 (median of 95.3%) and also keep a low V150 and V200 dose at 24.5 and 11.2 cc, respectively. Complete treatment can be done within a 30-min time slot, which includes implant verification, setup, and irradiation time as well as wound dressing. Conclusion SAVI has been implemented at UC San Diego for accelerated partial breast irradiation with excellent tumor bed conformance and minimal normal tissue exposure. Patient positioning is the key to identifying any inter-fraction device motion. Device asymmetry or tissue conformance has been shown to resolve itself 24 h after the device implantation. The device can be implemented into an existing HDR program with minimal effort.
The Calculus of Consent: a compass for my professional journey

The Calculus of Consent as well as its authors have been with me from the start of my professional journey, which began at the University of Virginia in fall 1963 (see Wagner 2004). Actually, it was The Calculus that led me to Charlottesville. The preceding year, I faced a quandary in applying to graduate schools: I was attracted to the logic of economic analysis but I preferred the material of political science. In discussing my quandary with Richard Bilas, who had joined the faculty of the University of Southern California in fall 1962 from the University of Virginia, he claimed that I could satisfy both desires by going to Virginia. So I read The Calculus and realized he was right. The correctness of that judgment was cemented my first week in Charlottesville. One of my four classes was public finance taught by Buchanan, who required us to write a series of short essays throughout the semester, each of which was discussed during the next class session. At the end of the first session, Buchanan assigned an essay on “The Problem of Fiscal Dimension.” He elaborated this assignment by saying that he had heard that if a fly were multiplied nine times, it couldn’t fly and might even crumble under its own weight. He continued by explaining that he thought the growth of government raised some questions about fiscal dimension that we should think about. When I asked if he could clarify what he was looking for in this essay, he shot back that if he could answer that question he wouldn’t ask us to write the essay! Unknown to me at that time, that assignment, along with Buchanan’s response to my question, have accompanied me throughout my academic career. What proved to be that continuing presence, moreover, was reinforced the next year when I took Tullock’s twosemester sequence titled something like “Theories of Simple and Complex Agreement.” For both Buchanan and Tullock and subsequently for me, a graduate classroom is not a forum where a professor explains the contents of what has already been published. While students are expected to read published work, the classroom itself is a forum for exploring and articulating ideas that might secure future publication. My approach to graduate instruction stems
The Structure of 2MASS Galaxy Clusters

We use a sample of galaxies from the Two Micron All Sky Survey Extended Source Catalog to refine a matched filter method of finding galaxy clusters that takes into account each galaxy's position, magnitude, and redshift if available. The matched filter postulates a radial density profile, luminosity function, and line-of-sight velocity distribution for cluster galaxies. We use this method to search for clusters in the galaxy catalog, which is complete to an extinction-corrected K-band magnitude of 13.25 and has spectroscopic redshifts for roughly 40% of the galaxies, including nearly all brighter than K = 11.25. We then use a stacking analysis to determine the average luminosity function, radial distribution, and velocity distribution of cluster galaxies in several richness classes, and use the results to update the parameters of the matched filter before repeating the cluster search. We also investigate the correlations between a cluster's richness and its velocity dispersion and core radius using these relations to refine priors that are applied during the cluster search process. After the second cluster search iteration, we repeat the stacking analysis. We find a cluster galaxy luminosity function that fits a Schechter form, with parameters M{sub K*} - 5log h = -23.64 {+-} 0.04more » and {alpha} = -1.07 {+-} 0.03. We can achieve a slightly better fit to our luminosity function by adding a Gaussian component on the bright end to represent the brightest cluster galaxy population. The radial number density profile of galaxies closely matches a projected Navarro-Frenk-White profile at intermediate radii, with deviations at small radii due to well-known cluster centering issues and outside the virial radius due to correlated structure. The velocity distributions are Gaussian in shape, with velocity dispersions that correlate strongly with richness.« less
Towards understanding the predictability of stock markets from the perspective of computational complexity

This paper initiates a study into the century-old issue of market predictability from the perspective of computational complexity. We develop a simple agent-based model for a stock market where the agents are traders equipped with simple trading strategies, and their trades together determine the stock prices. Computer simulations show that a basic case of this model is already capable of generating price graphs which are visually similar to the recent price movements of high tech stocks. In the general model, we prove that if there are a large number of traders but they employ a relatively small number of strategies, then there is a polynomial-time algorithm for predicting future price movements with high accuracy. On the other hand, if the number of strategies is large, market prediction becomes complete in two new computational complexity classes CPP and BCPP, where PNP[O(log n)]e BCPP e CPP = PP. These computational completeness results open up a novel possibility that the price graph of a actual stock could be sufficiently deterministic for various prediction goals but appear random to all polynomial-time prediction algorithms.
The Diverse Infrared Properties of a Complete Sample of Star-forming Dwarf Galaxies

We present mid-infrared Spitzer Space Telescope observations of a complete sample of star-forming dwarf galaxies selected from the KPNO International Spectroscopic Survey. The galaxies span a wide range in mid-infrared properties. Contrary to expectations, some of the galaxies emit strongly at 8 μm, indicating the presence of hot dust and/or PAHs. The ratio of this mid-infrared dust emission to the stellar emission is compared with the galaxies' luminosity, star formation rate, metallicity, and optical reddening. We find that the ratio of the 8.0 μm dust emission to the stellar emission is more strongly correlated with the star formation rate than it is with the metallicity or the optical reddening in these systems. Nonetheless, there is a correlation between the 8.0 μm luminosity and metallicity. The slope of this luminosity-metallicity correlation is shallower than corresponding ones in the B band and 3.6 μm. The precise nature of the 8.0 μm emission seen in these galaxies (i.e., PAH vs. hot dust or some combination of the two) will require future study, including deep mid-IR spectroscopy.
Short separating geodesics for multiply connected domains

We consider the following questions: given a hyperbolic plane domain and a separation of its complement into two disjoint closed sets each of which contains at least two points, what is the shortest closed hyperbolic geodesic which separates these sets and is it a simple closed curve? We show that a shortest geodesic always exists although in general it may not be simple. However, one can also always find a shortest simple curve and we call such a geodesic a meridian of the domain. We prove that, although they are not in general uniquely defined, if one of the sets of the separation of the complement is connected, then they are unique and are also the shortest possible geodesics which separate the complement in this fashion.
Explicit Integration of the Full Symmetric Toda Hierarchy and the Sorting Property

We give an explicit formula for the solution to the initial-value problem of the full symmetric Toda hierarchy. The formula is obtained by the orthogonalization procedure of Szego, and is also interpreted as a consequence of the QR factorization method of Symes. The sorting property of the dynamics is also proved for the case of a generic symmetric matrix in the sense described in the text, and generalizations of tridagonal formulae are given for the case of matrices with 2M+1 nonzero diagonals.
HABITABLE CLIMATES : THE INFLUENCE OF OBLIQUITY

Extrasolar terrestrial planets with the potential to host life might have large obliquities or be subject to strong obliquity variations. We revisit the habitability of oblique planets with an energy balance climate model (EBM) allowing for dynamical transitions to ice-covered snowball states as a result of ice-albedo feedback. Despite the great simplicity of our EBM, it captures reasonably well the seasonal cycle of global energetic fluxes at Earth's surface. It also performs satisfactorily against a full-physics climate model of a highly oblique Earth-like planet, in an unusual regime of circulation dominated by heat transport from the poles to the equator. Climates on oblique terrestrial planets can violate global radiative balance through much of their seasonal cycle, which limits the usefulness of simple radiative equilibrium arguments. High obliquity planets have severe climates, with large amplitude seasonal variations, but they are not necessarily more prone to global snowball transitions than low obliquity planets. We find that terrestrial planets with massive CO2 atmospheres, typically expected in the outer regions of habitable zones, can also be subject to such dynamical snowball transitions. Some of the snowball climates investigated for CO2-rich atmospheres experience partial atmospheric collapse. Since long-term CO2 atmospheric build-up acts as a climatic thermostat for habitable planets, partial CO2 collapse could limit the habitability of such planets. A terrestrial planet's habitability may thus sensitively depend on its short-term climatic stability.
A study of laminar hypersonic cavity flows

An experimental investigation of the distributions of pressure, recovery factor, and heattraiisfer coefficient on 20° cones incorporating annular cavities was carried out in helium at MOO = 11 • The effects of Reynolds number, cavity length-depth ratio, and reattachment region geometry were studied. Attention was confined to the laminar, "open" cavity flow regime. The results showed that the pressure was virtually constant on the cavity floor for a cavity length-depth ratio less than seven. A definite pressure gradient appeared at higher length-depth ratios. The recovery factor was virtually constant within the cavity and downstream and was very close to the laminar attached-flow value. The distribution of heattransfer coefficient showed a pronounced minimum on the cavity floor, falling to about 10 to 20% of the attached-flow value. The heat-transfer coefficient passed through a maximum in the reattachment region, then went asymptotically to a value lower than the attached-flow value. The integrated heat-transfer rate in the separated flow region was in excellent agreement with Chapman's laminar mixing layer theory, being about 55% of the attached-flow value. However, this significant reduction in heat transfer was almost nullified by the increased heat-transfer rates close to reattachment.
On Tails of Perpetuities

We establish an upper bound on the tails of a random variable that arises as a solution of a stochastic difference equation. In the nonnegative case our bound is similar to a lower bound obtained in Goldie and Grubel (1996).
On a property of plane curves

Abstract Let γ : [ 0 , 1 ] → [ 0 , 1 ] 2 be a continuous curve such that γ ( 0 ) = ( 0 , 0 ) , γ ( 1 ) = ( 1 , 1 ) , and γ ( t ) ∈ ( 0 , 1 ) 2 for all t ∈ ( 0 , 1 ) . We prove that, for each n ∈ N , there exists a sequence of points A i , 0 ⩽ i ⩽ n + 1 , on γ such that A 0 = ( 0 , 0 ) , A n + 1 = ( 1 , 1 ) , and the sequences π 1 ( A i A i + 1 → ) and π 2 ( A i A i + 1 → ) , 0 ⩽ i ⩽ n , are positive and the same up to order, where π 1 , π 2 are projections on the axes.