cssi/SciSciGPT-SciSciNet huggingface dataset:
The end curve theorem for normal complex surface singularities

We prove the "End Curve Theorem," which states that a normal surface singularity .X;o/ with rational homology sphere link 6 is a splice quotient singularity if and only if it has an end curve function for each leaf of a good resolution tree. An "end curve function" is an analytic function .X;o/! .C; 0/ whose zero set intersects 6 in the knot given by a meridian curve of the exceptional curve corresponding to the given leaf. A "splice quotient singularity".X;o/ is described by giving an explicit set of equations describ- ing its universal abelian cover as a complete intersection in C t , wheret is the number of leaves in the resolution graph for.X;o/, together with an explicit description of the covering transformation group. Among the immediate consequences of the End Curve Theorem are the previously known results: .X;o/ is a splice quotient if it is weighted homogeneous (Neumann 1981), or rational or minimally elliptic (Okuma 2005).
Weighted Sato–Tate Vertical Distribution of the Satake Parameter of Maass Forms on PGL(N)

We formulate a conjectured orthogonality relation between the Fourier coefficients of Maass forms on PGL(N). Based on the works of Goldfeld-Kontorovich and Blomer for N=3, and on our conjecture for N≥4, we prove a weighted vertical equidistribution theorem (with respect to the generalized Sato–Tate measure) for the Satake parameter of Maass forms at a finite prime. For N=3, the rate of convergence for the equidistribution theorem is obtained.
Determinants of Migration to Central Cities: A Comment

This study critiques a prior study of migration determinants according to race, i.e., white migration versus nonwhite migration, to central cities in the U.S. We find evidence strongly suggesting simultaneity bias. In addition, the specification in the article being evaluated is flawed because it assumes that white migrants are attracted to central cities with higher income rather than higher incomes for whites. Similarly, the study being examined by this Comment is flawed because it assumes nonwhites are attracted not to areas with higher nonwhite incomes but with higher overall incomes. Furthermore, this Comment finds specification errors in the failure to adopt race-specific unemployment rates.
Regulated commercial harvest to manage overabundant white-tailed deer: An idea to consider?

Declines in hunter recruitment coupled with dramatic growth in numbers of white-tailed deer (Odocoileus virginianus) have challenged our ability to manage deer populations through regulated hunting. We review the efficacy of current regulated hunting methods and explain how they are unable to reduce deer numbers sufficiently in some environments. Regulated commercial harvest would provide an additional tool to help state wildlife agencies manage overabundant populations of white-tailed deer. We outline potential means to govern regulated commercial deer harvest and explain how it is compatible with the North American Model of Wildlife Conservation. We identified several benefits, including reduced overabundant populations of deer; source of healthy, natural, green, locally produced protein; promotion of economic growth, entrepreneurship, and market expansion; and public engagement and appreciation. We also address expected concerns associated with this concept, such as privatization of wildlife; overexploitation; food safety; competition with existing commodities; law enforcement; and challenges of changing laws, regulations, and attitudes. We suggest developing a professional forum to address the issue of regulated commercial harvest of white-tailed deer and other overabundant species of wildlife. 2011 The Wildlife Society.
Unemployment, wage rigidity, and the returns to education

Abstract If real wage formation is rigid then an increase in the proportion of skilled workers in the economy may increase the relative unemployment rate of the unskilled, thus rendering them ‘obsolete’ or ‘unemployable’. This in turn may generate increasing returns to education and multiple equilibria. A human intensive equilibrium may coexist with a physical capital intensive equilibrium. The ranking of equilibria with respect to welfare and unemployment is a priori ambiguous.
Vlasov-Fokker-Planck modeling of plasma near hohlraum walls heated with nanosecond laser pulses calculated using the ray tracing equations

Here, we present 2D numerical modeling of near critical density plasma using a fully implicit Vlasov-Fokker-Planck code, IMPACTA, with an implementation of a ray tracing add-on package. This allows to model inverse brehmsstrahlung heating as a laser travels through a plasma by solving the ray tracing equations. In certain situations, such as those at the critical surface at the walls of a hohlraum, magnetic fields are generated through the crossed temperature and electron density gradients (the Biermann Battery effect).
Multiplexed on-column protein digestion and capillary electrophoresis for high-throughput comprehensive peptide mapping.

Abstract A novel scheme based on multiplexed capillary electrophoresis (CE) has been developed for high-throughput, low-cost and comprehensive peptide mapping. Orthogonal peptide maps of the protein of interest were obtained by using multiple reaction conditions with three different enzymes (trypsin, pepsin, and chymotrypsin), and multiple separation conditions with six zone electrophoresis buffers and two micellar electrokinetic chromatography (MEKC) buffers. Fifteen nanoliters of two protein samples (β-lactoglobulin A and β-lactoglobulin B) were separately mixed on-column and digested independently at 37 °C for 10 min to produce peptides in a 20-capillary system. The resulting peptides were detected simultaneously at 214 nm by a photodiode array detector. The overall analysis time from reaction to detection was about 40 min.
Towards a SDLCQ test of the Maldacena conjecture

Abstract We consider the Maldacena conjecture applied to the near horizon geometry of a D1-brane in the supergravity approximation and present numerical results of a test of the conjecture against the boundary field theory calculation using DLCQ. We previously calculated the two-point function of the stress-energy tensor on the supergravity side; the methods of Gubser, Klebanov, Polyakov, and Witten were used. On the field theory side, we derived an explicit expression for the two-point function in terms of data that may be extracted from the supersymmetric discrete light cone quantization (SDLCQ) calculation at a given harmonic resolution. This yielded a well defined numerical algorithm for computing the two-point function. For the supersymmetric Yang-Mills theory with 16 supercharges that arises in the Maldacena conjecture, the algorithm is perfectly well defined; however, the size of the numerical computation prevented us from obtaining a numerical check of the conjecture. We now present numerical results with approximately 1000 times as many states as we previously considered. These results support the Maldacena conjecture and are within 10–15% of the predicted numerical results in some regions. Our results are still not sufficient to demonstrate convergence, and, therefore, cannot be considered to a numerical proof of the conjecture. We present a method for using a “flavor” symmetry to greatly reduce the size of the basis and discuss a numerical method that we use which is particularly well suited for this type of matrix element calculation.
Hole Scavenging and Photo-Stimulated Recombination of Electron−Hole Pairs in Aqueous TiO2 Nanoparticles

It is shown that 532 and 1064 nm laser photoexcitation of trapped electrons generated by 355 nm photolysis of aqueous titania (TiO2) nanoparticles causes rapid photobleaching of their absorbance band in the visible and near-IR. This photobleaching occurs within the duration of the laser pulse (3 ns fwhm); it is caused by photoinduced electron detrapping followed by rapid recombination of the resulting free electron and a trapped hole. The quantum yield for the electron photobleaching is ca. 0.28 for 532 nm and ca. 0.024 for 1064 nm photoexcitation. Complete separation of the spectral contributions from trapped electron and hole is demonstrated using glycerol as a selective hole scavenger. When glycerol is added to the solution, some light-absorbing holes are scavenged promptly within the duration of the 355 nm photoexcitation pulse, some are scavenged at a slower rate over the first 200 ns after the 355 nm pulse, and the rest are not scavenged, even at high concentration of the scavenger (>10 vol. %). A r...
DEEP INELASTIC ELECTRON--PROTON AND ELECTRON--NEUTRON SCATTERING.

Formulae for the structure functionsW1 andW2 are obtained by means of the statistical approach to the Veneziano model together with pomeron dominance. A form forW2 is obtained that scales and agrees well with the data. The question of the scaling ofW1 is discussed. Phase-space corrections and generalized Glauber corrections are then studied in connection with e-D scattering; they are found to be small. Hence, contributions from both the pomeron and lower trajectories are used to generalize the model. Satisfactory agreement is obtained.
Keck Spectroscopy of Three Gravitational Lens Systems Discovered in the JVAS and CLASS Surveys

We present spectra of three gravitational lens systems taken with the Low Resolution Imaging Spectrograph on the W. M. Keck telescopes. All of the systems were discovered in the JVAS and CLASS radio surveys, which were designed to find lenses suitable for measuring H0. Previous spectra of these systems had low signal-to-noise ratios, and only one of the source redshifts was secure. Our observations provide unambiguous lens and source redshifts for all of the systems, with (zl, zs) = (0.4060, 1.339), (0.5990, 1.535), and (0.4144, 1.589) for B0712+472, B1030+074, and B1600+434, respectively. The observed image splittings in the systems imply that the masses of the lensing galaxies within their Einstein rings are 5.4 × 1010, 1.2 × 1011, and 6.3 × 1010 h-1 M⊙. The resulting V-band mass-to-light ratios for B0712+472 and B1030+074, measured inside their Einstein ring radii, are ~10 h (M/L)⊙,V, slightly higher than values observed in nearby elliptical galaxies. For B1600+434, the mass-to-light ratio is 48 h (M/L)⊙,V. This high value can be explained, at least in part, by the prominent dust lane running through the galaxy. Two of the three lens systems show evidence of variability, so monitoring may yield a time delay and thus a measurement of H0.
Evolution of Differentially Rotating Supermassive Stars to the Onset of Bar Instability

Thermal emission from a rotating, supermassive star will cause the configuration to contract slowly and spin up. If internal viscosity and magnetic fields are sufficiently weak, the contracting star will rotate differentially. For each of the six initial angular momentum distributions considered, a cooling supermassive star will likely encounter the dynamical bar mode instability, which may trigger the growth of nonaxisymmetric bars. This scenario will lead to the generation of long-wavelength gravitational waves, which could be detectable by future space-based laser interferometers like the Laser Interferometer Space Antenna.
Uniform measures on inverse limit spaces

Motivated by problems from dynamic economic models, we consider the problem of defining a uniform measure on inverse limit spaces. Let where X is a compact metric space and f is continuous, onto and piecewise one-to-one and . Then starting with a measure μ1 on the Borel sets , we recursively construct a sequence of probability measures on satisfying for each and . This sequence of probability measures is then uniquely extended to a probability measure on the inverse limit space Y. If μ1 is a uniform measure, we argue that the measure induced on the inverse limit space by the recursively constructed sequence of measures is a uniform measure. As such, the measure has uses in economic theory for policy evaluation and in dynamical systems in providing an ambient measure (when Lebesgue measure is not available) with which to define a Sinai–Ruelle–Bowen (SRB) measure or a metric attractor for the shift map on the inverse limit space.
Antiphospholipid thrombosis syndromes

Antiphospholipid antibodies are associated strongly with thrombosis and are the most common of the acquired blood protein defects causing thrombosis. Although the precise mechanisms whereby antiphospholipid antibodies alter hemostasis to induce a hypercoagulable state remain unclear, numerous theories, as previously discussed, have been advanced. The most common thrombotic events associated with ACLAs are deep vein thrombosis and pulmonary embolus (type I syndrome), coronary or peripheral artery thrombosis (type II syndrome), or cerebrovascular/retinal vessel thrombosis (type III syndrome), and occasionally patients present with mixtures (type IV syndrome). Patients with type V disease are those with antiphospholipid antibodies and RMS. It is as yet unclear how many seemingly normal individuals who may never develop manifestations of antiphospholipid syndrome (type VI) harbor asymptomatic antiphospholipid antibodies. The relative frequency of ACLAs in association with arterial and venous thrombosis strongly suggests that they should be looked for in any individual with unexplained thrombosis; all three idiotypes (IgG, IgA, and IgM) should be assessed. Also, the type of syndrome (I-VI) should be defined, if possible, because this identification may dictate both the type and the duration of immediate and long-term anticoagulant therapy. Unlike those patients with ACLAs, patients with primary LA-thrombosis syndrome usually have venous thrombosis. Because the aPTT is unreliable in patients with LA (prolonged in only approximately 40%-50% of patients) and usually is not prolonged in patients with ACLAs, definitive tests, including ELISA for ACLA, the dilute Russell's viper venom time for LA, hexagonal phospholipid-neutralization procedure, and B-2-GP-I (IgG, IgA, and IgM) should be ordered immediately when suspecting antiphospholipid syndrome or in individuals with otherwise unexplained thrombotic or thromboembolic events. If these test results are negative, subgroups also should be assessedin the appropriate clinical setting. Most patients with antiphospholipid thrombosis syndrome will fail to respond to warfarin therapy, and except for retinal vascular thrombosis, may fail some types of antiplatelet therapy, so it is of major importance to make this diagnosis so patients can be treated with the most effective therapy for secondary prevention-LMWH or unfractionated heparin in most instances and clopidogrel in some instances.
Prospects for measuring the mass of heavy, long-lived neutral particles that decay to photons

We describe a novel way to measure the mass of heavy, long-lived neutral particles that decay to photons using collider experiments. We focus on a Light Neutralino and Gravitino model in a Gauge Mediated Supersymmetry Breaking scenario where the neutralino has a long-lifetime (O(ns)) as it is not excluded by current experiments. To illustrate our method and give sensitivity estimates we use recent CDF results and a pro- duction mechanism where sparticles are produced via φi ! e χ 1 e χ 1 ! (γ e G)(γ e G) in which φi indicates a neutral scalar boson, e χ 1 is the lightest neutralino and e G is the gravitino, as a full set of background shapes and rates are available. Events can be observed in the exclusive photon plus Missing ET final state where one photon arrives at the detector with a delayed time of arrival. Surprisingly, a simple measurement of the slope of the delayed- time distribution with the full CDF dataset is largely insensitive to all but the e χ 1 mass and allows for the possibility of determining its mass to approximately 25% of itself.
Vertigo: Comparing structural models of imperfect behavior in experimental games

We introduce the game of Vertigo to study learning in experimental games with one-sided incomplete information. Our models allow players to make errors when choosing their actions. We compare six models where the players are modeled as sophisticated (taking errors in action into account when constructing strategies) or unsophisticated on one dimension, and employ Bayes' rule, a faster updating rule, or no updating at all on the second. Using a fully Bayesian structural econometric approach, we find that unsophisticated models perform better than sophisticated models, and models with no (or slower) updating perform better than models with faster updating.
Splitting of three nearly mass degenerate neutrinos

Abstract Assuming the canonical seesaw mechanism together with an SO(3) family symmetry for leptons, broken only by the charged-lepton masses, I show that the three neutrinos of Majorana mass m0 are split radiatively in two loops by a maximum finite calculable amount of order 10 −9 m 0 . This is very suitable for dark matter and vacuum solar neutrino oscillations. I also discuss how atmospheric neutrino oscillations can be incorporated.
Joint Soft-Decision Cooperative Spectrum Sensing and Power Control in Multiband Cognitive Radios

We consider joint optimization of cooperative spectrum sensing, channel access and power allocation in an overlay multiband cognitive radio network. A soft-decision cooperative spectrum sensing concept using continuous-valued sensing test statistics is considered, instead of making hard binary decisions as in traditional hypothesis testing spectrum sensing schemes. The channel access decision about whether to access the channel or not is relaxed into allowing the secondary user to access channels with some probability. The sensing decision is made at the secondary base station based on the sensing statistics received from all or a subset of secondary users. This joint optimization problem is aimed at maximizing the secondary users' sum instantaneous throughput while keeping the interference to primary users under a specified threshold. The problem is shown to be a convex optimization problem and the Lagrangian dual method is employed to obtain the optimal solution. Two heuristic algorithms are also proposed to reduce computational complexity. We also discuss an alternative formulation where additionally interference to individual PUs is also constrained. Simulation results show that our soft sensing based algorithm significantly outperforms a traditional hard decision sensing algorithm.
A practical method for the synthesis of highly enantioenriched trans-1,2-amino alcohols.

A highly enantioselective addition of phenyl carbamate to meso-epoxides has been developed to efficiently generate protected trans-1,2-amino alcohols. This transformation is promoted by an oligomeric (salen)Co–OTf catalyst and has been used to prepare two useful 2-aminocycloalkanol hydrochlorides in enantiopure form on a multigram scale from commercially available starting materials.
The Tate conjecture for K3 surfaces in odd characteristic

We show that the classical Kuga–Satake construction gives rise, away from characteristic $$2$$ , to an open immersion from the moduli of primitively polarized K3 surfaces (of any fixed degree) to a certain regular integral model for a Shimura variety of orthogonal type. This allows us to attach to every polarized K3 surface in odd characteristic an abelian variety such that divisors on the surface can be identified with certain endomorphisms of the attached abelian variety. In turn, this reduces the Tate conjecture for K3 surfaces over finitely generated fields of odd characteristic to a version of the Tate conjecture for certain endomorphisms on the attached Kuga–Satake abelian variety, which we prove. As a by-product of our methods, we also show that the moduli stack of primitively polarized K3 surfaces of degree $$2d$$ is quasi-projective and, when $$d$$ is not divisible by $$p^2$$ , is geometrically irreducible in characteristic $$p$$ . We indicate how the same method applies to prove the Tate conjecture for co-dimension $$2$$ cycles on cubic fourfolds.
YOUTH DEPRESSION AND FUTURE CRIMINAL BEHAVIOR

While the contemporaneous association between mental health problems and criminal behavior has been explored in the literature, the long-term consequences of such problems, depression in particular, have received much less attention. Using data from the National Longitudinal Study of Adolescent Health (Add Health), we examine the effect of depression during adolescence on the probability of engaging in a number of criminal behaviors later in life. In our analysis, we control for a rich set of individual-, family-, and neighborhood-level factors to account for conditions that may be correlated with both childhood depression and adult criminality. One novelty in our approach is the estimation of school and sibling fixed effects models to account for unobserved heterogeneity at the neighborhood and family levels. Furthermore, we exploit the longitudinal nature of our data set to account for baseline differences in criminal behavior. The empirical estimates show that adolescents who suffer from depression face a substantially increased probability of engaging in property crime. We find little evidence that adolescent depression predicts the likelihood of engaging in violent crime or the selling of illicit drugs. Our estimates imply that the lower-bound economic cost of property crime associated with adolescent depression is approximately 227 million dollars per year. (JEL I10, K42)
Soluble Chlorofullerenes C60Cl2,4,6,8,10. Synthesis, Purification, Compositional Analysis, Stability, and Experimental/Theoretical Structure Elucidation, Including the X-ray Structure of C1-C60Cl10

The efficacy of various analytical techniques for the characterization of products of C60 chlorination reactions were evaluated by (i) using samples of C60Cl6 of known purity and (ii) repeating a number of literature syntheses reported to yield pure C60Cln compounds. The techniques were NMR, UV−vis, IR, and Raman spectroscopy, FAB, MALDI, LDI, ESI, and APCI mass spectrometry, HPLC, TGA, elemental analysis, and single-crystal X-ray diffraction. Most of these techniques are shown to give ambiguous or erroneous results, calling into question the composition and/or purity of nearly all C60Cln compounds reported to date. The optimum analytical method for chlorofullerenes was found to be a combination of HPLC and either MALDI or APCI mass spectrometry. For the first time, the chlorination of C60 by ICl, ICl3, and Cl2 was studied in detail using dynamic HPLC analysis and APCI mass spectrometry. Suitable conditions were found for the preparation of the new chlorofullerenes 1,7-C60Cl2, 1,9-C60Cl2, 1,6,9,18-C60Cl4,...
Supersymmetric gauge theories with a free algebra of invariants

Abstract We study the low-energy dynamics of all N = 1 supersymmetric gauge theories whose basic gauge-invariant fields are unconstrained. This set includes all theories whose matter Dynkin index is less than the index of the adjoint representation. We study the dynamically generated superpotential in these theories, and show that there is a W = 0 branch if and only if anomaly matching is satisfied at the origin. An interesting example studied in detail is SO (13) with a spinor, a theory with a dynamically generated W and no anomaly matching at the origin. It flows via the Higgs mechanism to SU (6) with a three-index antisymmetric tensor, a theory with a W = 0 branch and anomaly matching at the origin.
Determinations of turbulent velocity fluctuations and mean particle radii in flames using scattered laser-power spectra

Abstract We describe a procedure for simultaneous determinations of mean particle radii and mean values of fluctuating velocity components in turbulent flows containing monodisperse particles. The results of in situ particle-size measurements are compared with estimates derived after withdrawals of samples.
Fluid flow analysis in microfluidic devices by spectral-domain optical Doppler tomography

Microfluidic devices are becoming increasingly popular for many applications, enabling biological and chemical reactions to be performed with nano- and picoliter sample volumes. Accurate measurement and monitoring of fluid flow behavior in the small channels of microfluidic systems is important for evaluating the performance of existing devices, and in the modeling and design of new microfluidic networks. We present here the results of experiments using spectral-domain optical Doppler tomography (SD-ODT) to measure fluid flow in single-layer microfluidic devices. The principles behind flow imaging with SD-ODT are reviewed, a method for velocity calibration is described, and cross-sectional and en-face images of fluid velocity in microfluidic channels are presented.
Solvent-free synthesis of monoacylaminals from the reaction of amides and aminals as precursors in carbinolamide synthesis

A solvent-free method of generating monoacylaminals by heating the amide and aminal starting materials in the presence of one another has been developed. Yields were generally between 45% and 65% with the monoacylaminal being isolated, needing no further purification after drying under high vacuum.
Metric structures in L 1 : dimension, snowflakes, and average distortion

We study the metric properties of finite subsets of L1. The analysis of such metrics is central to a number of important algorithmic problems involving the cut structure of weighted graphs, including the Sparsest Cut Problem, one of the most compelling open problems in the field of approximation algorithms. Additionally, many open questions in geometric non-linear functional analysis involve the properties of finite subsets of L1.We present some new observations concerning the relation of L1 to dimension, topology, and Euclidean distortion. We show that every n-point subset of L1 embeds into L2 with average distortion O(√log n), yielding the first evidence that the conjectured worst-case bound of O(√log n) is valid. We also address the issue of dimension reduction in Lp for p ∈ (1, 2). We resolve a question left open by M. Charikar and A. Sahai [Dimension reduction in the l1 norm, in: Proceedings of the 43rd Annual IEEE Conference on Foundations of Computer Science, ACM, 2002, pp. 251-260] concerning the impossibility of dimension reduction with a linear map in the above cases, and we show that a natural variant of the recent example of Brinkman and Charikar [On the impossibility of dimension reduction in l1, in: Proceedings of the 44th Annual IEEE Conference on Foundations of Computer Science, ACM, 2003, pp. 514-523], cannot be used to prove a lower bound for the non-linear case. This is acomplished by exhibiting constant-distortion embeddings of snowflaked planar metrics into Euclidean space.
α-Aryl-Substituted Allenamides in an Imino-Nazarov Cyclization Cascade Catalyzed by Au(I)

An imino-Nazarov cyclization using α-aryl-substituted allenamides is described. This gold(I)-catalyzed cascade is efficient and regioselective in constructing a diverse array of synthetically useful aromatic-ring fused cyclopentenamides. The success in this transformation represents a solution to the challenge in establishing an imino-Nazarov cyclization process.
Global surface reconstruction by purposive control of observer motion

Abstract What viewpoint-control strategies are important for performing global visual exploration tasks such as searching for specific surface markings, building a global model of an arbitrary object, or recognizing an object? In this paper we consider the task of purposefully controlling the motion of an active, monocular observer in order to recover a global description of a smooth, arbitrarily-shaped object. We formulate global surface reconstruction as the task of controlling the motion of the observer so that the visible rim slides over the maximal, connected, reconstructible surface regions intersecting the visible rim at the initial viewpoint. We show that these regions are bounded by a subset of the visual event curves defined on the surface. By studying the epipolar parameterization, we develop two basic strategies that allow reconstruction of a surface region around any point in a reconstructible surface region. These strategies control viewpoint to achieve and maintain a well-defined geometric relationship with the object's surface, rely only on information extracted directly from images (e.g., tangents to the occluding contour), and are simple enough to be performed in real time. We then show how global surface reconstruction can be provably achieved by (1) appropriately integrating these strategies to iteratively “grow” the reconstructed regions, and (2) obeying four simple rules.
Oscillator Strengths for Fine-Structure Transitions in S III

Oscillator strengths and transition probabilities for transitions among the fine-structure levels of the terms belonging to the 3s(sup 2)3p(sup 2), 3s3p(sup 3), 3s(sup 2)3p3d, 3s(sup 2)3p4s, 3s(sup 2)3p4p, and 3s(sup 2)3p4d configurations of S III are calculated using extensive configuration-interaction wave functions. The relativistic effects in intermediate coupling are incorporated by means of the Breit-Pauli Hamiltonian. Small adjustments to the diagonal elements of the Hamiltonian matrices have been made so that the energy splittings are as close as possible to the experimental values. The present results are compared with other available calculations and experiments.
The energy crisis and its impact on the stability of the demand for factors of production

Abstract This paper addresses the question of the stability of the demand for the factors of production at the aggregate level for United States manufacturing over the period 1947 to 1976. The results are conclusive. The demand for capital and labour has remained virtually constant over the period of investigation whilst the relative importance of the factors affecting the demand for energy has changed in a statistically significant fashion.
A new brown dwarf desert? A scarcity of wide ultracool binaries

We present the results of a deep-imaging search for wide companions to low-mass stars and brown dwarfs using NSFCam on the Infrared Telescope Facility. We searched a sample of 132 M7-L8 dwarfs to magnitude limits of J ~ 20.5 and K ~ 18.5, corresponding to secondary-to-primary mass ratios of ~0.5. No companions were found with separations between 2'' and 31'' (~40 to ~1000 AU). This null result implies a wide companion frequency below 2.3% at the 95% confidence level within the sensitivity limits of the survey. Preliminary modeling efforts indicate that we could have detected 85% of companions more massive than 0.05 M⊙ and 50% above 0.03 M⊙.
Decentralized matching markets with endogenous salaries

Abstract In a Shapley–Shubik assignment problem with a supermodular output matrix, we consider games in which each firm makes a take-it-or-leave-it salary offer to one applicant, and a match is made only when the offer is accepted by her. We consider both one-shot and multistage games. In either game, we show that there can be many equilibrium salary vectors which are higher or lower than the minimum competitive salary vector. If we exclude artificial equilibria, applicants' equilibrium salary vectors are bounded above by the minimal competitive salary vector, while firms' equilibrium payoff vectors are bounded below by the payoff vector under the minimum competitive salary vector. This suggests that adopting the minimum competitive salary vector as the equilibrium outcome in decentralized markets does not have a strong justification.
Vulnerable options in supply chains: Effects of supplier competition

Concerned with the risk of supplier default, a firm may choose to diversify its orders among multiple suppliers. Furthermore, the discrepancy in production lead-times among suppliers furnishes a firm with a valuable option to defer ordering decisions until uncertainty has been partially resolved. The suppliers also have an option: to defer their pricing decisions. Using a single-period, multi-stage model of a two-echelon supply chain with competing risky suppliers and a single manufacturer, this paper investigates how the supplier default risk and default co-dependence affect manufacturer procurement and production decisions, supplier pricing decisions, firms profits, and the deferment option value and how the introduction of the deferment option alters supplier competition. © 2006 Wiley Periodicals, Inc. Naval Research Logistics 2006
Reduction of Hg(II) to Hg(0) by Magnetite

Mercury (Hg) is a highly toxic element, and its contamination of groundwater presents a significant threat to terrestrial ecosystems. Understanding the geochemical processes that mediate mercury transformations in the subsurface is necessary to predict its fate and transport. In this study, we investigated the redox transformation of mercuric Hg (Hg[II]) in the presence of the Fe(II)/Fe(III) mixed valence iron oxide mineral magnetite. Kinetic and spectroscopic experiments were performed to elucidate reaction rates and mechanisms. The experimental data demonstrated that reaction of Hg(II) with magnetite resulted in the loss of Hg(II) and the formation of volatile elemental Hg (Hg[0]). Kinetic experiments showed that Hg(II) reduction occurred within minutes, with reaction rates increasing with increasing magnetite surface area (0.5 to 2 m2/L) and solution pH (4.8 to 6.7), and decreasing with increasing chloride concentration (10(-6) to 10(-2) mol/L). Mossbauer spectroscopic analysis of reacted magnetite samples revealed a decrease in Fe(II) content, corresponding to the oxidation of Fe(II) to Fe(III) in the magnetite structure. X-ray photoelectron spectroscopy detected the presence of Hg(II) on magnetite surfaces, implying that adsorption is involved in the electron transfer process. These results suggest that Hg(II) reaction with solid-phase Fe(II) is a kinetically favorable pathway for Hg(II) reduction in magnetite-hearing environmental systems.
Angular Momentum Control in Nonlinear Flight

A rational approach to control angular motion of aircraft in highly nonlinear e ight regimes is presented. The method seeks to change the angular velocity by directing the aerodynamic moment so that it is most effective in achieving this objective. Validation of the method is presented by simulating two spins of a light aircraft. The approach is shown to be successful in stopping the rotation for effecting spin recovery. Nomenclature G = moment vector H = angular momentum vector I = moment of inertia L, M, N = moment vector components in body axes P = roll rate Q = pitch rate R = yaw rate u = control vector V = airspeed a = angle of attack b = sideslip angle d A = aileron dee ection d E = elevator dee ection d R = rudder dee ection ! = angular velocity vector
THE 1998 NOVEMBER 14 OCCULTATION OF GSC 0622-00345 BY SATURN. II. STRATOSPHERIC THERMAL PROFILE, POWER SPECTRUM, AND GRAVITY WAVES

On 1998 November 14, Saturn and its rings occulted the star GSC 0622-00345. The occultation latitude was 55.{sup 0}5 S. This paper analyzes the 2.3 {mu}m light curve derived by Harrington and French. A fixed-baseline isothermal fit to the light curve has a temperature of 140 {+-} 3 K, assuming a mean molecular mass of 2.35 AMU. The thermal profile obtained by numerical inversion is valid between 1 and 60 {mu}bar. The vertical temperature gradient is > 0.2 K km{sup -1} more stable than the adiabatic lapse rate, but it still shows the alternating-rounded-spiked features seen in many temperature gradient profiles from other atmospheric occultations and usually attributed to breaking gravity (buoyancy) waves. We conduct a wavelet analysis of the thermal profile, and show that, even with our low level of noise, scintillation due to turbulence in Earth's atmosphere can produce large temperature swings in light-curve inversions. Spurious periodic features in the 'reliable' region of a wavelet amplitude spectrum can exceed 0.3 K in our data. We also show that gravity-wave model fits to noisy isothermal light curves can lead to convincing wave 'detections'. We provide new significance tests for localized wavelet amplitudes, wave model fits, and global power spectramore » of inverted occultation light curves by assessing the effects of pre- and post-occultation noise on these parameters. Based on these tests, we detect several significant ridges and isolated peaks in wavelet amplitude, to which we fit a gravity wave model. We also strongly detect the global power spectrum of thermal fluctuations in Saturn's atmosphere, which resembles the 'universal' (modified Desaubies) curve associated with saturated spectra of propagating gravity waves on Earth and Jupiter.« less
Novel Solution Phase Strategy for the Synthesis of Chemical Libraries Containing Small Organic Molecules

A simple, versatile, and general approach to the solution phase, parallel synthesis of chemical libraries conducted on a generalized or universal template, which allows the preparation of multi-mil...
Some thoughts on solving the radiative transfer equation in stochastic media using polynomial chaos and Wick products as applied to radiative equilibrium

Abstract The solution of the stochastic radiative transfer equation is described from the point of view of polynomial chaos and Wick products. Polynomial chaos is best suited for properties that are random fields. When the properties are characterized by white noise, this method can become computationally infeasible because of the need to solve coupled differential equations. When the radiative processes are Gaussian, then the expense is tolerable. For white noise the Wick product approach offers a reasonable level of computational expense in determining a strong solution. The method is demonstrated by computing the effect of an absorption coefficient corrupted by white noise. The method yields reasonable estimates of the standard deviations of the radiative behavior with less cost than the usual Monte Carlo approach. A substantial amount of further research is needed before the method can be applied to coupled radiative/conduction problems.
A potential-flow, deformable-body model for fluid–structure interactions with compact vorticity: application to animal swimming measurements

This paper presents an approach to quantify the unsteady fluid forces, moments and mass transport generated by swimming animals, based on measurements of the surrounding flow field. These goals are accomplished within a framework that is independent of the vorticity field, making it unnecessary to directly resolve boundary layers on the animal, body–vortex interactions, or interactions among vortex lines in the wake. Instead, the method identifies Lagrangian coherent structures in the flow, whose dynamics in flows with compact vorticity are shown to be well approximated by potential flow concepts, especially the Kirchhoff and deformation potentials from deformable body theory. Examples of the application of these methods are given for pectoral fin locomotion of the bluegill sunfish and undulatory swimming of jellyfish, and the methods are validated by analysis of a canonical starting vortex ring flow. The transition to a Lagrangian approach toward animal swimming measurements suggests the possibility of implementing recently developed particle tracking (vis-a-vis DPIV) techniques for fully three-dimensional measurements of animal swimming.
Frequency dependence of spin‐lattice relaxation times of lipid bilayers

2H and 13C spin‐lattice (T1) relaxation time studies of 1,2‐dipalmitoyl‐sn‐glycero‐3‐phospho‐ choline (DPPC) in the lamellar, liquid crystalline (Lα) phase are discussed. It is shown that the T−11 results as a function of Larmor frequency ω0 are statistically better described by an ω−1/20 dependence than by an ω−10 or ω−20 dependence.
Syn-Oxidative cyclizations of trishomoallylic alcohols: Stereoselective and stereospecific synthesis of trans-tetrahydropyranyl alcohols

Abstract Trifluoroacetylperrhenate promotes the hydroxyl-directed syn -oxidative cyclization of trishomoallylic alcohols. The cyclization reaction is highly stereospecific and stereoselective, providing a novel and efficient synthesis of trans -2,6-disubstituted tetrahydropyranyl alcohols.
Pairwise Wave Interactions in Ideal Polytropic Gases

We consider the problem of resolving all pairwise interactions of shock waves, contact waves, and rarefaction waves in the one-dimensional flow of an ideal polytropic gas. Here, resolving an interaction means to determine the types of the three outgoing (backward, contact, and forward) waves in the Riemann problem defined by the extreme left and right states of the two incoming waves, together with possible vacuum formation. This problem has been considered by several authors and turns out to be surprisingly involved. For each type of interaction (head-on, involving a contact, or overtaking) the outcome depends on the strengths of the incoming waves. In the case of overtaking waves the type of the reflected wave also depends on the value of the adiabatic constant. Our analysis provides a complete breakdown and gives the exact outcome of each interaction.
Statistics of quasars multiply imaged by galaxy clusters

We compute the expected number of quasars multiply imaged by cluster-size dark halos for current wide-field quasar surveys by carrying out a large ensemble of ray-tracing simulations through clusters from a cosmological N-body simulation of the ΛCDM cosmology, with power spectrum normalization σ8 = 0.95. Our calculation predicts ~4 quasar lenses with splittings θ > 10'' in the SDSS spectroscopic quasar sample, consistent with the recent discovery of the wide separation lens SDSS J1004+4112, which has θ = 14.6''. The SDSS faint photometric quasar survey will contain ~12 multiply imaged quasars with splittings θ > 10''. Of these, ~2 will be lenses with θ > 30'', and ~2 will be at high redshift (zs ~ 4).
Orthogonal Codes for Robust Low-Cost Communication

Orthogonal coding schemes, known to asymptotically achieve the capacity per unit cost (CPUC) for single-user ergodic memoryless channels with a zero-cost input symbol, are investigated for single-user compound memoryless channels, which exhibit uncertainties in their input-output statistical relationships. A minimax formulation is adopted to attain robustness. First, a class of achievable rates per unit cost (ARPUC) is derived, and its utility is demonstrated through several representative case studies. Second, when the uncertainty set of channel transition statistics satisfies a convexity property, optimization is performed over the class of ARPUC through utilizing results of minimax robustness. The resulting CPUC lower bound indicates the ultimate performance of the orthogonal coding scheme, and coincides with the CPUC under certain restrictive conditions. Finally, still under the convexity property, it is shown that the CPUC can generally be achieved, through utilizing a so-called mixed strategy in which an orthogonal code contains an appropriate composition of different nonzero-cost input symbols.
Synchrotron Mössbauer study of Fe-bearing pyrope at high pressures and temperatures

Iron-bearing pyrope, an abundant silicate mineral in the Earth’s upper mantle, exhibits the largest quadrupole splitting (QS) in Mossbauer spectra among all common Fe-bearing rock-forming silicate minerals at ambient conditions, with a value of ~3.5 mm/s. Knowledge regarding the hyperfine QS of mantle minerals at relevant pressures and temperatures ( P-T ) is needed to aid our understanding of the electronic spin and valence states of iron and local site distortion in major mantle silicate minerals. The latter, in turn, is relevant for coherent model of electronic and mechanical properties of the Earth’s mantle. Here we have measured synchrotron Mossbauer spectra (SMS) of the high-spin Fe2+ in Fe-bearing pyrope garnet with two distinct compositions, (Mg0.8Fe0.2)3Al2Si3O12 (py80alm20) and Fe3Al2Si3O12 (alm100), up to 30 GPa and 750 K. Analyses of the SMS spectra revealed that the high-spin Fe2+ ions in the distorted dodecahedral site exhibit extremely high QS of ~3.4–3.6 mm/s and relatively high chemical shifts (CS) of ~1.2–1.3 mm/s at high P-T , indicating that the Fe2+ ions remain in the high-spin state. An increase in the Fe content in the pyrope-almandine series only slightly decreases the QS and CS of the Fe2+ ions. To decipher the energy separation (Δ) between the two lowest energy levels of the 3 d electrons of the Fe2+ ions in the sample, the d xy and d z 2 orbitals, the QS values of py80alm20 at high P-T were further evaluated using Huggins model. Our modeled results show that the Δ of the Fe2+ ions in py80alm20 is ~156 meV at high P-T , and may be correlated to the change of the crystal-field energy splitting (ΔC). Comparison of the QS, Δ, and ΔC values of Fe2+ ions in the distorted dodecahedral sites of pyrope and silicate perovskite indicates that the high-spin Fe2+ with the extremely high QS can remain stable at high P-T conditions, consistent with recent theoretical predictions. Our results thus contribute to our current understanding of the hyperfine parameters and spin and valence states of iron in the mantle silicate minerals at high P-T .
World-Sheet Supersymmetry Without Contact Terms

Abstract Green and Seiberg showed that, in simple treatments of fermionic string theory, it is necessary to introduce contact interactions when vertex operators collide. Otherwise, certain superconformal Ward identities would be violated. In this note, we show how these contact terms arise naturally when proper account is taken of the superconformal geometry involved when punctures collide. More precisely, we show that there is no contact term at all! Rather, corrections arise to the “naive” formula when the boundary of moduli space is described correctly.
Alumina-mediated microwave thermolysis: A new approach to deprotection of benzyl esters

Abstract A simple and high yielding method for deprotection of benzyl esters is described which occurs under mild and solvent-free conditions on alumina surface using microwave irradiation.
Effects of shrinkage on conductivity of isotropic conductive adhesives

Our previous study proved that intimate contact between conductive fillers caused by resin cure shrinkage, rather than lubricant removal, was the main mechanism for establishment of conductivity of isotropic conductive adhesives (ICAs). The purpose of the present study was to investigate the changes in properties, especially in dimension (cure shrinkage), of an ICA during cure and to correlate them with establishment of conductivity. An ICA was cured nonisothermally by a temperature increase from 30 to 250°C; and its heat flow, storage modulus, dimension change, and electrical conductivity were studied with a differential scanning calorimeter (DSC), rheometer, thermomechanical analyzer (TMA), and electrical multimeter, respectively. It was found that all of these properties changed dramatically over the same small range of temperature. Changes in these four properties of this ICA with time in the course of an isothermal cure were also investigated. It was found that all of the properties showed significant changes within the same period of time. In addition, the conductivities of three different ICA formulations which were filled with a blank Ag powder and whose resins had different cure shrinkages were measured and compared. From this study, it was concluded that (a) conductive adhesives achieved high conductivity only when enough cure shrinkage was achieved, and (b) ICAs with higher cure shrinkage showed higher conductivity.
Future applications of cryptography

Abstract No longer prohibitively expensive, encryption of data in motion and at rest is a new potentially cost-effective thread in the fabric of controls appropriate for many medium-to-high-risk applications of computers and communications. This paper looks at recent and probable developments in commercially available encryption products, and sets forth application oriented ways in which these products are expected to be used. The reasons why and why not to use encryption are also provided.