cssi/SciSciGPT-SciSciNet huggingface dataset:
Beyond Flux-Limited Diffusion: Parallel Algorithms for Multidimensional Radiation Hydrodynamics

This paper presents a new code for performing multidimensional radiation hydrodynamic (RHD) simulations on parallel computers involving anisotropic radiation fields and nonequilibrium effects. The radiation evolution modules described here encapsulate the physics provided by the serial algorithm of Stone et al. but add new functionality both with regard to physics and numerics. In detailing our method, we have documented both the analytic and discrete forms of the radiation moment solution and the variable tensor Eddington factor (VTEF) closure term. We have described three different methods for computing a short-characteristic formal solution to the transfer equation, from which our VTEF closure term is derived. Two of these techniques include time dependence, a primary physics enhancement of the method not present in the Stone algorithm. An additional physics modification is the adoption of a matter-radiation coupling scheme which is particularly robust for nonequilibrium problems and which also reduces the operations cost of our radiation moment solution. Two key numerical components of our implementation are highlighted: the biconjugate gradient linear system solver, written for general use on massively parallel computers, and our techniques for parallelizing both the radiation moment solution and the transfer solution. Additionally, we present a suite of test problems with a much broader scope than that covered in the Stone work; new tests include nonequilibrium Marshak waves, two-dimensional "shadow" tests showing the one-sided illumination of an opaque cloud, and full RHD+VTEF calculations of radiating shocks. We use the results of these tests to assess the virtues and vices of the method as currently implemented, and we identify a key area in which the method may be improved. We conclude that radiation moment solutions closed with variable tensor Eddington factors show a qualitative improvement over results obtained with flux-limited diffusion, and further that this approach has a bright future in the context of parallel RHD simulations in astrophysics.
Modulation of Amyloid Precursor Protein Metabolism by X11α/Mint-1 A DELETION ANALYSIS OF PROTEIN-PROTEIN INTERACTION DOMAINS

Abstract Modulation of amyloid precursor protein (APP) metabolism plays a pivotal role in the pathogenesis of Alzheimer's disease. The phosphotyrosine-binding/protein interaction (PTB/PI) domain of X11α, a neuronal cytosolic adaptor protein, binds to the YENPTY sequence in the cytoplasmic carboxyl terminus of APP. This interaction prolongs the half-life of APP and inhibits Aβ40 and Aβ42 secretion. X11α/Mint-1 has multiple protein-protein interaction domains, a Munc-18 interaction domain (MID), a Cask/Lin-2 interaction domain (CID), a PTB/PI domain, and two PDZ domains. These X11α protein interaction domains may modulate its effect on APP processing. To test this hypothesis, we performed a deletion analysis of X11α effects on metabolism of APP695 Swedish (K595N/M596L) (APPsw) by transient cotransfection of HEK 293 cells with: 1) X11α (X11α-wt, N-MID-CID-PTB-PDZ-PDZ-C), 2) amino-terminal deletion (X11α-ΔN, PTB-PDZ-PDZ), 3) carboxyl-terminal deletion (X11α-ΔPDZ, MID-CID-PTB), or 4) deletion of both termini (PTB domain only, PTB). The carboxyl terminus of X11α was required for stabilization of APPsw in cells. In contrast, the amino terminus of X11α was required to stimulate APPs secretion. X11α, X11α-ΔN, and X11α-PTB, but not X11α-ΔPDZ, were effective inhibitors of Aβ40 and Aβ42 secretion. These results suggest that additional protein interaction domains of X11α modulate various aspects of APP metabolism.
Dedekind cotangent sums

Let a,a1,...,ad be positive integers, m1,...,md nonnegative integers, and z1,...,zd complex numbers. We study expressions of the form X k mod a d Y j=1 cot (mj) kaj a + z j . Here the sum is taken over all k mod a for which the summand is not singular. These Dedekind cotangent sums generalize and unify various arithmetic sums introduced by Dedekind, Rademacher, Apostol, Carlitz, Zagier, Berndt, Meyer, Sczech, and Dieter. Generalized Dedekind sums appear in various areas such as analytic and algebraic number theory, topology, algebraic and combinatorial geometry, and algorithmic complexity. We prove reciprocity laws, Petersson-Knopp identities, and computability statements for the Dedekind cotangent sums.
The discovery of growth hormone-releasing hormone.

This article has been reproduced with permission from the Journal of Clinical Endocrinology & Metabolism.
Dissecting the Stanley partition function

Let p(n) denote the number of unrestricted partitions of n. For i=0, 2, let pi (n) denote the number of partitions π of n such that O(π) - O (π1)≡ i (mod4). Here O(π) denotes the number of odd parts of the partition π and π' is the conjugate of π. Stanley [Amer. Math. Monthly 109 (2002) 760; Adv. Appl. Math., to appear] derived an infinite product representation for the generating function of p0(n) - p2(n). Recently, Swisher [The Andrews-Stanley partition function and p(n), preprint, submitted for publication] employed the circle method to show that limn→ ∞ p0(n)/p(n) = ½ (i) and that for sufficiently large n 2p0(n) > p(n) if n ≡ 0, 1 (mod4), 2p0(n) |p0(2n + 1)| - p2(2n + 1)|, n > 0.Two proofs of this surprising inequality are given. The first one uses the Gollnitz-Gordon partition theorem. The second one is an immediate corollary of a new partition inequality, which we prove in a combinatorial manner. Our methods are elementary. We use only Jacobi's triple product identity and some naive upper bound estimates.
Evolution of Star-forming and Active Galaxies in Nearby Clusters

We have used optical spectroscopy to investigate the active galaxy populations in a sample of 20 nearby Abell clusters. The targets were identified on the basis of 1.4 GHz radio emission, which identifies them as either active galactic nuclei (AGNs) or galaxies forming stars at rates comparable to or greater than that of the Milky Way. The spectra were used to characterize the galaxies via their emission and absorption features. The spectroscopy results reveal a significant population of star-forming galaxies with large amounts of nuclear dust extinction. This extinction eliminates bluer emission lines such as [O II] from the spectra of these galaxies, meaning their star formation could easily be overlooked in studies that focus on such features. Around 20% of the cluster star-forming galaxies have spectra of this type. The radial distributions of active galaxies in clusters show a strong segregation between star-forming galaxies and AGNs, with star-forming galaxies broadly distributed and AGNs preferentially in the cluster cores. The radial distribution of the dusty star-forming galaxies is more centrally concentrated than the star-forming galaxies in general, which argues that they are a consequence of some cluster environmental effect. Furthermore, we note that such galaxies may be identified using their 4000 A break strengths. We find that discrepancies in reported radio luminosity functions for AGNs are likely the result of classification differences. There exists a large population of cluster galaxies whose radio fluxes, far-infrared fluxes, and optical magnitudes suggest their radio emission may be powered by stars yet whose spectra lack emission lines. Understanding the nature of these galaxies is critical to assessing the importance of AGNs in the radio luminosity function at low luminosities. We also find that regardless of this population, the crossover point where the radio luminosity function is composed equally of star-forming galaxies and AGNs occurs at lower luminosities in clusters than in the field. This is likely a simple consequence of the reduction in star formation in cluster galaxies and the morphological mix in clusters compared with the field.
Helical Polymer 1/∞[P2Se62-]: Strong Second Harmonic Generation Response and Phase-Change Properties of Its K and Rb Salts

The selenophosphates A2P2Se6 (A = K, Rb) crystallize in the chiral trigonal space group P3121, with a = 7.2728(9) A, c = 18.872(4) A, and Z = 3 at 298(2) K and a = 14.4916(7) A, c = 18.7999(17) A, and Z = 12 at 173(2) K for K+ salt and a = 7.2982(5) A, c = 19.0019(16) A, and Z = 3 at 100(2) K for Rb+ salt. The A2P2Se6 feature parallel one-dimensional helical chains of 1/∞[P2Se62-] which depict an oxidative polymerization of the ethane-like [P2Se6]4- anion. On cooling well below room temperature K2P2Se6 exhibits a displacive phase transition to a crystallographic subgroup and forms a superstructure with a cell doubling along the a- and b-axes. The Rb analogue does not exhibit the phase transition. The compounds are air stable and show reversible glass-crystal phase-change behavior with a band gap red shift of 0.11 and 0.22 eV for K+ and Rb+ salts, respectively. Raman spectroscopy, 31P magic angle spinning solid-state NMR, and pair distribution function (PDF) analysis for crystalline and glassy K2P2Se6 give...
Effects of truncation in modal representations of thermal convection

The Galerkin equations for convection in a sphere are examined to determine which physical processes are neglected by the severe truncation of the equations of motion. It is demonstrated that the gross features of the flow are affected by truncation in the horizontal direction, with all of the models considered being well resolved in the vertical direction. One of the effects of truncation is to enhance the high-wave number end of the kinetic energy and thermal variance spectra. The examples cited indicate that as long as the kinetic energy spectrum decreases with wave number, a truncation gives a qualitatively correct solution. Conclusions are tested by calculating solutions to the equations of motion for several values of the Rayleigh number and the limit of horizontal spatial resolution.
Grand openings for cloverite

MICROPOROUS crystalline solids comprise a class of materials whose main uses are as adsorbents, catalysts and ion exchangers. Zeolites, the best known of these, are built from tetrahedral units of SiO_4 and AlO_4 which connect to form crystalline structures with cavities and/or channels large enough to accommodate (or host) guest molecules. The degree of structural specificity achievable with molecular sieves is highly advantageous in the synthesis of materials with precise functions, such as optically active materials.
Electron radiation belts of the solar system

[1] To address factors dictating similarities and differences between solar system radiation belts, we present comparisons between relativistic electron radiation belt spectra of all five strongly magnetized planets: Earth, Jupiter, Saturn, Uranus, and Neptune. We choose observed electron spectra with the highest intensities near ∼1 MeV and compare them against expectations based on the so-called Kennel-Petschek limit (KP). For evaluating the KP limit, we begin with a recently published relativistic formulation and then add several refinements of our own. Specifically, we utilized a more flexible analytic spectral shape that allows us to accurately fit observed radiation belt spectra, and we examine the differential characteristics of the KP limit. We demonstrate that the previous finding that KP-limited spectra take on an E−1 shape in the nonrelativistic formulation is also roughly preserved with the relativistic formulation; this shape is observed at several of the planets studied. We also conclude that three factors limit the highest relativistic electron radiation belt intensities within solar system planetary magnetospheres: (1) plasma whistler mode interactions that limit differential spectral intensities to a differential Kennel-Petschek limit (Earth, Jupiter, and Uranus), (2) the absence of robust acceleration processes associated with injection dynamics (Neptune), and (3) material interactions between the radiation electrons and clouds of gas and dust (Saturn).
Stability crossing set for systems with two scalar-delay channels

Abstract This article studies the stability crossing set of linear time-invariant systems with two scalar-delay channels. This study is crucial to the complete stability analysis along the idea of D-subdivision method. The characteristic quasipolynomial of such systems contains an exponential term with the sum of two delays in its exponent (cross term). A complete parameterization and geometric characterization of the stability crossing set is conducted. It was found instrumental to relate it to an associated quasipolynomial without such a cross term through an elimination process. However, a spurious stability crossing set may arise in this process. A revised parameterization method is derived that automatically eliminates such a spurious stability crossing set.
Au-catalyzed synthesis of (1Z,3E)-2-pivaloxy-1,3-dienes from propargylic pivalates.

Propargylic pivalates with electronically unbiased internal alkynes are selectively transformed into (1Z,3E)-2-pivaloxy-1,3-dienes containing various functionalities. The unusual selectivity of 1,2-acyloxy migration over the structurally preferred 3,3-rearrangement is realized. This reaction is highly stereoselective and offers rapid access to dienes for one-pot intra-/intermolecular Diels−Alder reactions either under thermal conditions or with Lewis acid catalysis.
The X-ray spectrum and time variability of narrow emission line galaxies

X-ray spectral and temporal observations are reported for six narrow emission line galaxies (NELGs), all of which are fitted by power-law X-ray spectra of energy slope 0.8 and have column densities in the line of sight greater than 1 x 10 to the 22nd atoms/sq cm. Three of the objects, NGC 526a, NGC 2110 and MCG-5-23-16 are variable in their X-ray flux, and the latter two, along with NGC 5506 and NGC 7582, showed detectable variability in at least one observation. The measured X-ray properties of these NELGs, which also included NGC 2992, strongly resemble those of previously-measured type 1 Seyferts of the same X-ray luminosity and lead to the conclusion of great similarity between the NELGs and low-luminosity type 1 Seyferts. The implications of these observations for the optical line-emitting region structure of these galaxies are discussed.
Proof of a symmetrized trace conjecture for the Abelian Born–Infeld Lagrangian

Abstract In this paper we prove a conjecture regarding the form of the Born–Infeld Lagrangian with a U(1) 2n gauge group after the elimination of the auxiliary fields. We show that the Lagrangian can be written as a symmetrized trace of Lorentz invariant bilinears in the field strength. More generally, we prove a theorem regarding certain solutions of unilateral matrix equations of arbitrary order. For solutions which have perturbative expansions in the matrix coefficients, the solution and all its positive powers are sums of terms which are symmetrized in all the matrix coefficients and of terms which are commutators.
Effect of dietary fat on the induction of hepatic microsomal cytochrome P450 isozymes by phenobarbital.

Dietary polyunsaturated fatty acid is needed for optimal induction of cytochrome P450. In this study we quantitated cytochrome P450 hemoproteins in male Sprague-Dawley rats that were starved for 36 hr and then refed a fat-free diet (FF) or a diet containing 20% corn oil for 4 days. Some received phenobarbital (Pb) sodium (80 mg/kg, i.p., daily) for 3 days prior to decapitation. Microsomal cytochrome P450 levels were measured by carbon monoxide binding spectra, and the P450 isozymes separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis were quantitated by gel scanner. Cytochrome P450 PB-B was quantitated by a Western blot technique. Rats fed FF diet and administered Pb had only 21% more microsomal P450 than non-induced controls, whereas rats fed 20% corn oil diet had 59% more P450 and Pb-treated rats fed 20% corn oil diet had 181% more P450 than FF controls. Analysis of gels showed 32, 59 and 124% more P450 protein, respectively, in FF Pb, corn oil control or corn oil Pb groups than in FF controls. Cytochrome P450 PB-B was not detected in non-induced groups, but quantitation by Western blot yielded 0.32 and 0.70 nmol/mg protein, respectively, in FF Pb and corn oil Pb groups. Our findings suggest that deprivation of dietary fat reduces the total amount of cytochrome P450 hemoprotein and its inducibility by Pb through decreased P450 hemoprotein synthesis. The limiting factor(s) restricting synthesis of new cytochrome P450 hemoproteins in rats refed a diet devoid of fat may be the inability to respond to the inducer (Pb) or the paucity of utilizable fatty acids needed for synthesis of the phospholipid matrix of the endoplasmic reticulum necessary for the support and proper juxtapositioning of these protein molecules.
Motion-Compensation and Noise Tolerance in Phase-Shifting Digital In-Line Holography

We present a technique to compensate for object motion in phase-shifting digital in-line holography. We also present a general inversion technique for arbitrary reference phases and amplitudes, including analysis of noise and error.
Importance of vertical mixing for additional sources of nitrate and iron to surface waters of the Columbia River plume: Implications for biology

The influence of the Columbia River plume on the distributions of nitrate and iron and their sources to coastal and shelf waters were examined. In contrast to other large estuaries, the Columbia River is a unique study area as it supplies very little nitrate (5 AM) and iron (14–30 nM) at salinities of 1–2 to coastal waters. Elevated nitrate and dissolved iron concentrations (as high as 20 AM and 20 nM) were observed, however, in the near field Columbia River plume at salinities of 20. Surface nitrate concentrations were higher than observed in the Columbia River itself and therefore must be added by entrainment of higher nitrate concentrations from subsurface coastal waters. Tidal flow was identified as an important factor in determining the chemical constituents of the Columbia River plume. During the rising flood tide, nitrate and iron were entrained into the plume waters resulting in concentrations of 15 AM and 6 nM, respectively. Conversely, during the ebb tide the concentrations of nitrate and total dissolved iron were reduced to 0.3–3 AM and 1–2 nM, respectively, with a concomitant increase in chlorophyll a concentrations. As these plume waters moved offshore the plume drifted directly westward, over a nitrate depleted water mass (b0.2 AM). The plume water was also identified to move southwards and offshore during upwelling conditions and nitrate concentrations in this far field plume were also depleted. Iron concentrations in the near-field Columbia River plume are sufficient to meet the biological demand. However, due to the low nitrate in the Columbia River itself, nitrate in the plume is primarily dependent on mixing with nitrate rich, cold, high salinity subsurface waters. Without such an additional source the plume rapidly becomes nitrate limited. D 2005 Elsevier B.V. All rights reserved.
Conformational inversion processes in phytic acid: NMR spectroscopic and molecular modeling studies

Abstract NMR spectroscopy and computational studies show that phytic acid undergoes pH- and ion-dependentconformational inversion from the 1ax/5eq form to the 5ax/1eq form. The kinetics and energetics of the conformational inversion process are discussed.
On orbifolds with discrete torsion

Abstract We consider the interpretation in classical geometry of conformal field theories constructed from orbifolds with discrete torsion. In examples we can analyze, these spacetimes contain “tringy regions” that from a classical point of view are singularities that are to be neither resolved nor blown up. Some of these models also give particularly simple and clear examples of mirror symmetry.
Modeling the Jet Kinematics of the Black Hole Microquasar XTE J1550–564: A Constraint on Spin-Orbit Alignment

Measurements of black hole spin made using the continuum-fitting method rely on the assumption that the inclination of the black hole's spin axis to our line of sight is the same as the orbital inclination angle i of the host binary system. The X-ray and radio jet data available for the microquasar XTE J1550-564 offer a rare opportunity to test this assumption. Following the work of others, we have modeled these data and thereby determined the inclination angleof the jet axis, which is presumed to be aligned with the black hole's spin axis. We find � ≈ 71 ◦ and place an upper limit on the difference between the spin and orbital inclinations of |� − i| < 12 deg (90% confidence). Our measurement tests for misalignment along the line of sight while providing no constraint perpendicular to this plane. Our constraint on the misalignment angle supports the prediction that the spinning black hole in XTE J1550-564 has aligned itself with the orbital plane and provides support for the measurement of its spin via the continuum- fitting method. Our conclusions are based on a simple and reasonable model of a pair of symmetric jets propagating into a low density cavity whose western wall is ≈ 20% closer to XTE J1550-564 than its eastern wall.
Total Synthesis of Bleomycin Group Antibiotics. Total Syntheses of Bleomycin Demethyl A2, Bleomycin A2, and Decarbamoyl Bleomycin Demethyl A2

The total syntheses of bleomycin A2 (1) by two routes are described. The final step in the synthesis of bleomycin A2 involves methylation of bleomycin demethyl A2 (2). This bleomycin derivative is of interest mechanistically, and can also provide access to other bleomycins via its known chemical conversion to bleomycinic acid. Accordingly, the synthetic strategy presented represents a particularly versatile approach for the elaboration of a wide variety of BLM congeners. Bleomycin was constructed from five key intermediates, the syntheses of which are described. 1,6-Di-O-acetyl-3,4-di-O-benzyl-2-O-[2,4,6-tri-O-acetyl-3-O-(N-acetylcarbamoyl)-α-d-mannopyranosyl]-β-l-gulopyranose (3) was converted quantitatively to its disaccharide chloride (4), the latter of which was condensed with Nα,Nim-bis(t-Boc)-(S)-erythro-β-hydroxyhistidine (7) to provide α-O-glycosidated product 16. The subsequent couplings with benzyl valerate 8, threonylbithiazole 9, and Nα-t-Boc-pyrimidoblamic acid (10) afforded access to bleomyc...
The notion of a random gauge and its interpretation

We introduce the concept of a random gauge. We propose two distinct types of random gauge that can be defined based on the concept of phase noise in scattering theory. In the context of quantum physics, we discuss a variety of possible realizations of this concept that can be connected to various Aharonov-other effects and make some connections with relativity as well.
Keeping Enceladus warm

Abstract Despite its small size, Enceladus emits considerable heat, especially at its south pole, even long after simple thermal models predict it should be frozen. Several sources of energy have been proposed as responsible for this heating, such as tidal dissipative heating (TDH), convection and shearing in the ice shell, and exothermic chemical reactions (e.g., serpentine formation). Crater relaxation simulations suggest that episodic heating events have occurred over long stretches of Enceladus’ history. Thermal history and hydrothermal simulations reported here show that a combination of steady plus episodic TDH heating could maintain at least a polar ocean to the present time. Hydrothermal circulation can play a significant role in mining Enceladus’ internal heat, facilitating the persistence of an ocean even to the present by focusing internal heat to the polar regions.
Mechanical properties of graphene nanoplatelet/epoxy composites

Due to their high specific stiffness, carbon-filled epoxy composites can be used in structural components in aircraft. Graphene nanoplatelets are short stacks of individual layers of graphite that ...
Synthesis of β- and γ-carbolines by the palladium/copper-catalyzed coupling and copper-catalyzed or thermal cyclization of terminal acetylenes

Abstract A variety of 3-substituted β- and γ-carbolines have been synthesized from N -substituted 3-iodoindole-2-carboxaldehydes and 2-bromoindole-3-carboxaldehydes, respectively. The coupling of these aldehydes with various terminal acetylenes using cat. PdCl 2 (PPh 3 ) 2 /CuI readily affords the corresponding alkynylindole carboxaldehydes, which have subsequently been converted to the corresponding tert -butylimines, which have then been cyclized to β- and γ-carbolines by either copper-catalyzed or thermal processes.
The dominant role of users in the scientific instrument innovation process

Abstract A sample of one hundred and eleven scientific instrument innovations was studied to determine the roles of instrument users and instrument manufacturers in the innovation processes which culminated in the successful commercialization of those instruments. Our key finding was that approximately 80% of the innovations judged by users to offer them a significant increment in functional utility were in fact invented, prototyped and first field-tested by users of the instrument rather than by an instrument manufacturer. The role of the first commercial manufacturer of the innovative instrument in all such cases was restricted, we found, to the performance of product engineering work on the user prototype (work which improved the prototype's reliability, ‘manufacturability’, and convenience of operation, while leaving its principles of operation intact) and to the manufacture and sale of the resulting innovative product. Thus, this research provides the interesting picture of an industry widely regarded as innovative in which the firms comprising the industry are not in themselves necessarily innovative, but rather — in 80% of the innovations sampled — only provide the product engineering and manufacturing function for innovative instrument users. We term the innovation pattern observed in scientific instruments a ‘user dominated’ one and suggest that such a pattern may play a major role in numerous industries.
Palladium-Catalyzed Tandem N-Arylation/Carboamination Reactions for the Stereoselective Synthesis of N-Aryl-2-benzyl Pyrrolidines

The tandem N-arylation/carboamination of γ-amino alkenes with two different aryl bromides provides rapid entry to differentially arylated N-aryl-2-benzyl pyrrolidine derivatives in good yields with good to excellent levels of diastereoselectivity. The selective diarylation is achieved in a one-pot process by an in situ modification of the palladium catalyst via phosphine ligand exchange.
Charge density matching in templated molybdates

Abstract The role of charge density matching in the formation of templated molybdates under mild hydrothermal conditions was investigated through the use of a series of structurally related amines: piperazine, 1,4-dimethylpiperazine, 2,5-dimethylpiperazine and 2,6-dimethylpiperazine. A series of reactions was conducted in which the relative mole fractions of each component were fixed at 2.5 MoO3:1 amine:330 H2O:2 H2SO4 in order to isolate the effects of the amine, the only variation between reactions was the structure of the amine. Four distinct polyoxomolybdates anions were observed, ranging from zero-dimensional β-[Mo8O26]4− molecular anions to [Mo3O10]n2n− and [Mo8O26]n4n− chains and [Mo5O16]n2n− layers. The primary influence over the structure of the molybdate anion is charge density matching with the protonated amine, which was quantified through surface area approximations based upon both calculated molecular surfaces and polyhedral representations of each anion. Secondary influences include amine symmetry and hydrogen-bonding preferences. The synthesis and characterization of two new compounds are reported. Crystal data: [C6H16N2][Mo3O10]·H2O (1), triclinic, P-1 (no. 2), a=8.0973(7) A, b=8.8819(9) A, c=11.5969(11) A, α=71.362(9)°, β=82.586(8)°, γ=74.213(8)°, Z=2, R/Rw=0.0262/0.0564, and [C6H16N2]2[Mo8O26] (2), monoclinic, P21/n (no. 14), a=7.9987(11) A, b=12.5324(19) A, c=16.003(3) A, β=97.393(14)°, Z=2, R/Rw=0.0189/0.0454.
Finescale Radar and Airmass Structure of the Comma Head of a Continental Winter Cyclone: The Role of Three Airstreams

AbstractData from airborne W-band radar, thermodynamic fields from the Weather Research and Forecasting (WRF) Model, and air parcel back trajectories from the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model are used to investigate the finescale reflectivity, vertical motion, and airmass structure of the comma head of a winter cyclone that produced 15–25 cm of snow across the U.S. Midwest on 29–30 January 2010.The comma head consisted of three vertically stacked air masses: from bottom to top, an arctic air mass of Canadian origin, a moist cloud-bearing air mass of Gulf of Mexico origin, and a drier air mass originating mostly at low altitudes over Baja California and the Mexican Plateau. The drier air mass capped the entire comma head and significantly influenced precipitation distribution and type across the storm, limiting cloud depth on the warm side, and creating instability with respect to ice-saturated ascent, cloud-top generating cells, and a seeder–feeder process on the col...
Data, Information, and Rural Environmental Policy: What Will the Next Ten Years Bring?

The next ten years will see an acceleration of three current trends: (1) the growing use of geographical information systems, (2) increasingly detailed farm-level record keeping, tracking the location and timing of fertilizer, pesticide, and water use, and (3) increased reporting requirements for farm-level chemical use. Combined, these changes will reduce the costs of monitoring and regulating farmer behavior. Yet, they may also allow information to substitute for both inputs and for regulation. Improved linkage of agronomic, economic, and environmental data can help ago-environmental subsidy programs achieve greater environmental benefits at lower budgetary cost and can help in the design of more flexible, less costly environmental regulations.
Traumatic Renal Artery Occlusion: A 15-Year Review

Background: To better define what constitutes appropriate treatment for traumatic renal artery occlusion, we report our 15-year experience in managing this injury. Methods: A retrospective chart review was performed to evaluate treatment outcomes and complications of 12 patients (13 injuries) who presented to our trauma centers with renal artery occlusion secondary to blunt injury. Results: Five of 12 patients underwent attempted surgical revascularization with a median warm ischemia time of 5 hours (range, 4.5-36 hours). Of these five patients, one required nephrectomy for inability to establish arterial flow, three demonstrated no function, and one had return to 9% differential function on postoperative renal scan. Seven patients did not have attempted revascularization, and none of them experienced immediate complications. Hypertension developed in three patients (43%) who required nephrectomy to control blood pressure at a mean of 5 months after injury (range, 3-7 months). Four patients remained asymptomatic and normotensive at a mean follow-up of 11 months (range, 4 weeks to 2.6 years). Conclusion: Surgical revascularization for traumatic renal artery occlusion seldom results in a successful outcome. Patients who are observed must have close follow-up for hypertension.
Array size scalability of passively coherently phased fiber laser arrays

We explore, by means of experiments and simulation, the power combining efficiency and power fluctuation of coherently phased 2, 4, 6, 8, 10, 12, 14, 16-channel fiber-laser arrays using fused 50:50 single-mode couplers. The measured evolution of power combining efficiency with array size agrees with simulations based on a new propagation model. For our particular system the power fluctuations due to small wavelength-scale length variations are seen to scale with array size as N(3). Beat spectra support the notion that a lack of coherently-combined supermodes in arrays of increasing size leads to a decrease in combined-power efficiency.
Kinetics and mechanism of hydrolysis of furosemide

Abstract Furosemide, a potent diuretic, has been found to give a low bioavailability profile when administered orally which potentially could be due to hydrolysis of the drug prior to absorption. An in vitro kinetic study was performed to elucidate the kinetics and hydrolysis mechanism of furosemide as a function of pH and temperature. In the acidic pH region, below the reported pKa of 3.8, the log K-pH profile indicated specific hydrogen ion catalysis on the undissociated species. In the basis pH region, furosemide hydrolysis is extremely slow. Using the Arrhenius parameters obtained from the studies, furosemide would have a half-life of 178 min under physiological conditions in the stomach of pH 1.0 and temperature of 37°C.
Knowledge management, supply chain technologies, and firm performance

Purpose – The purpose of this paper is to provide a conceptual overview of the relationship between knowledge management, supply chain technology investments, and overall firm performance. Additionally, a historical review of supply chain development is offered along with a comprehensive list of supply chain measures currently in use and a discussion of how those measures align within the overall firm strategy.Design/methodology/approach – Building on knowledge management theory, the paper argues herein that the transitory nature of firm‐level differentiation and the ease with which competitors gain access to each others' business strategies demand that firms stay flexible. It is also argued that translating firm knowledge resources into useable knowledge management capabilities may enable firms to enhance their likelihood of competitive advantage.Findings – Many leading firms drive towards new advantages through supply chain information capturing investments. By capturing data and mining that information...
Vanadium-Catalyzed Epoxidations of Olefinic Alcohols in Liquid Carbon Dioxide

The selective epoxidation of olefinic alcohols with t-BuOOH in the presence of vanadium catalysts proceeds in liquid carbon dioxide with high conversions and selectivities. Rates measured in liquid CO2 for the oxovanadium(V) triisopropoxide catalyzed epoxidation of allylic and homoallylic alcohols using tert-butyl hydroperoxide are comparable to those measured in methylene chloride, toluene, and n-hexane. The reactivity of the vanadium(IV) bis(acetylacetonato) oxide catalyst in liquid CO2 was found to be substantially lower than in organic solvents, presumably due to its low solubility in CO2. Highly fluorinated acac-type ligands increased the catalytic reactivity of VO(acac)2-catalyzed epoxidations by enhancing catalyst precursor solubility. Heterogeneous epoxidation reactions were also carried out in liquid CO2 using vanadium complexes supported on cation-exchange polymers.
The Shape of gravity in a warped deformed conifold

We study the spectrum of the gravitational modes in Minkowski spacetime due to a 6-dimensional warped deformed conifold, i.e., a warped throat, in superstring theory. After identifying the zero mode as the usual 4D graviton, we present the KK spectrum as well as other excitation modes. Gluing the throat to the bulk (a realistic scenario), we see that the graviton has a rather uniform probability distribution everywhere while a KK mode is peaked in the throat, as expected. Due to the suppressed measure of the throat in the wave function normalization, we find that a KK mode's probability in the bulk can be comparable to that of the graviton mode. We also present the tunneling probabilities of a KK mode from the inflationary throat to the bulk and to another throat. Due to resonance effect, the latter may not be suppressed as natively expected. Implication of this property to reheating after brane inflation is discussed.
Cosmic-ray-dominated AGN Jets and the Formation of X-ray Cavities in Galaxy Clusters

It is widely accepted that feedback from active galactic nuclei (AGNs) plays a key role in the evolution of gas in groups and clusters of galaxies. Unequivocal evidence comes from quasi-spherical X-ray cavities observed near cluster centers having sizes ranging from a few to tens of kpc, some containing non-thermal radio emission. Cavities apparently evolve from the interaction of AGN jets with the intracluster medium (ICM). However, in numerical simulations it has been difficult to create such fat cavities from narrow jets. Ultra-hot thermal jets dominated by kinetic energy typically penetrate deep into the ICM, forming radially elongated cavities at large radii unlike those observed. Here, we study very light jets dominated energetically by relativistic cosmic rays (CRs) with axisymmetric hydrodynamic simulations, investigating the jet evolution both when they are active and when they are later turned off. We find that, when the thermal gas density in a CR-dominated jet is sufficiently low, the jet has a correspondingly low inertia and thus decelerates quickly in the ICM. Furthermore, CR pressure causes the jet to expand laterally, and to encounter and displace more decelerating ICM gas, naturally producing fat cavities near cluster centers similar to those observed. Our calculations of cavity formation imply that AGN jets responsible for creating fat X-ray cavities (radio bubbles) are very light and dominated by CRs. This scenario is consistent with radio observations of Fanaroff-Riley type I jets that appear to decelerate rapidly, produce strong synchrotron emission, and expand typically at distances of a few kpc from the central AGN.
Improved synthesis of 3-aryl isoxazoles containing fused aromatic rings

A critical comparison of methods to prepare sterically hindered 3-aryl isoxazoles containing fused aromatic rings using the nitrile oxide cycloaddition (NOC) reveal that modification of the method of Bode, Hachisu, Matsuura, and Suzuki (BHMS), utilizing either triethylamine as base or sodium enolates of the diketone, ketoester, and ketoamide dipolarophiles, respectively, was the method of choice for this transformation.
A Facile Synthesis of 1,4-Diketones from Organolithium Reagents and N,N,N′,N′-Tetramethylsuccinamide

Abstract The reaction of organolithium reagents (alkyl, aryl, heteroaryl) with N,N,N′,N′-tetramethylsuccinamide at 0 °C gives good yields of the corresponding 1,4-diketones.
Performance analysis of algebraic soft decoding of reed-solomon codes over binary symmetric and erasure channels

In this paper, we characterize the decoding region of algebraic soft decoding (ASD) [4] of Reed-Solomon (RS) codes over erasure channels and binary symmetric channel (BSC). Optimal multiplicity assignment strategies (MAS) are investigated and tight bounds are derived to show the ASD can significantly outperform conventional Berlekamp Massey (BM) decoding over these channels for a wide code rate range. The analysis technique can also be extended to other channel models, e.g., RS coded modulation over erasure channels
Pilot–ATC Communication Conflicts: Implications for NextGen

In the planned NextGen aviation operations, it will be critical to ensure shared situational understanding and cooperative problem solving between aircrews and air traffic controllers (ATC). A first step in predicting how future changes will impact flight crews and ATC is to examine the current system and to pinpoint problematic areas that could be ameliorated or exacerbated by advanced automation and heavier traffic density. In this study, we coded Aviation Safety Reporting System (ASRS) reports identified as having communication conflicts between pilots and ATC. Results describe types of conflict, operational context, phase of flight, operator states, and situations conducive to communication conflicts, risk perception differences, and inappropriate resolution strategies. Reports suggest that high workload approach and landing phases are conducive to communication conflicts, that different interpretations of the same information might lead to conflict, and that operator state could impact communication ...
Global/local analysis of composite plates with cutouts

The study focuses on the development of a simple and accurate global/local method for calculating the static response of stepped, simply-supported, isotropic and composite plates with circular and elliptical cutouts. The approach primarily involves two steps. In the first step a global approach, the Ritz method, is used to calculate the response of the structure. Displacement based Ritz functions for the plate without the cutout are augmented with a perturbation function, which is accurate for uniform thickness plates only, to account for the cutout. The Ritz solution does not accurately satisfy the natural boundary conditions at the cut-out boundary, nor does it accurately model the discontinuities caused by abrupt thickness changes. Therefore, a second step, local in nature is taken in which a small area in the vicinity of the hole and encompassing other points of singularities is discretized using a fine finite element mesh. The displacement boundary conditions for the local region are obtained from the global Ritz analysis. The chosen perturbation function is reliable for circular cutout in uniform plates, therefore elliptical cutouts were suitably transformed to circular shapes using conformal mapping. The methodology is then applied to the analysis of composite plates, and its usefulness successfully proved in such cases. The proposed approach resulted in accurate prediction of stresses, with considerable savings in CPU time and data storage for composite flat panels.
Analysis of the effect of heated jet flow on the far field radiation from a noise source

The influence on jet noise radiation of the interaction with the heated moving flow of a parallel twin jet is investigated. An analytical model of jet shielding is developed which consists of the sound field emitted from a stationary, discrete frequency point source impinging on a cylinder of locally parallel flow. The zones in which the various shielding mechanisms dominate are analyzed using the model. The effects of parameters such as jet temperature and flow speed are examined. It is found that the results obtained using the model are comparable to the experimental results for a point noise source impinging on a subsonic isothermal air jet.
Reflectivity of some materials at 94 GHz

In order to better understand the characteristics of discrete natural land clutter at millimeter wavelengths, an experimental investigation of the relative reflectivity of various materials at 94 GHz was performed using a substitution technique. The data show that nonconducting materials have a relative reflectivity on the order of 2–3%, and that absorbed water can increase the relative reflectivity significantly.
Direct measurements of (p, γ) cross-sections at astrophysical energies using radioactive beams and the Daresbury Recoil Separator

There are a number of astrophysical environments in which the path of nucleosynthesis proceeds through proton-rich nuclei. These nuclei have traditionally not been available as beams, and thus proton-capture reactions on these nuclei could only be studied indirectly. At the Holifield Radioactive Ion Beam Facility (HRIBF), some of the first direct measurements of (p,\( \gamma\)) cross-sections on radioactive beams have been made. The Daresbury Recoil Separator (DRS) has been used to separate the recoils of interest from the unreacted primary beam and identify them in an isobutane-filled ionization counter. First data from 17F (p,\( \gamma\)18Ne and 7Be (p,\( \gamma\)8B measurements are presented.
Dynamical grid method for time dependent simulations of axisymmetric instabilities in tokamaks

A natural nonorthogonal time-dependent coordinate transformation based on the magnetic field lines is utilized for the numerical integration of the two-dimensional axisymmetric time-dependent ideal MHD equations in tokamak geometry. The finite-difference grid is treated as a dynamical variable, and its equations of motion are integrated simultaneously with those for the fluid and magnetic field. The method is applicable to tokamak systems of arbitrary pressure and cross section. It is particularly useful for the nearly incompressible ideal MHD modes which are of interest in tokamak stability studies.
Computational analysis of three-dimensional turbulent flow around a bluff body in ground proximity

The Reynolds-averaged Navier-Stokes equations, together with the equations of the k-e model of turbulence, were solved numerically in a general curvilinear coordinate system for three-dimensional turbulent flows around Ahmed's vehicle-like body. The numerical computations were performed for various afterbody upper-surface slant angles at a constant Reynolds number of 4.3 x 10 based on the body length. A multistep correction procedure was incorporated into the incompressibility condition, and the solution of the Poisson equation for pressure was obtained from the conjugate gradient method. A second-order discretization scheme for the convection term was applied to reduce the numerical diffusion. Most of the essential measured features of the flowfield around Ahmed's vehicle-like body in ground proximity, such as the formation of trailing vortices and the reverse flow region resulting from separation, were well predicted.
Tides in the middle and upper atmospheres of Mars and Venus

Abstract Current knowledge of solar tides in the middle and upper atmospheres of Mars and Venus is summarized, including Sun-synchronous tides on both planets; nonmigrating tides on Mars due to radiative/topographic interactions near the surface; and acceleration/deceleration of the zonal mean flows on Mars and Venus due to tidal interactions.
Discrete dipole approximation for low-energy photoelectron emission from NaCl nanoparticles

Abstract This work presents a model for the photoemission of electrons from sodium chloride nanoparticles 50–500 nm in size, illuminated by vacuum ultraviolet light with energy ranging from 9.4 to 10.9 eV. The discrete dipole approximation is used to calculate the electromagnetic field inside the particles, from which the two-dimensional angular distribution of emitted electrons is simulated. The emission is found to favor the particle's geometrically illuminated side, and this asymmetry is compared to previous measurements performed at the Lawrence Berkeley National Laboratory. By modeling the nanoparticles as spheres, the Berkeley group is able to semi-quantitatively account for the observed asymmetry. Here however, the particles are modeled as cubes, which are closer to their actual shape, and the interaction of an emitted electron with the particle surface is also considered. The end result shows that the modeled emission asymmetry for these low-energy electrons is more sensitive to the interaction with the particle-surface than to the specific particle shape, i.e., a sphere or cube.
Defusing the Exploding Offer: The Farpoint Gambit

Exploding offers, as opposed to normally expiring offers, are coercive, ethically questionable tactics where very often, a more powerful offeror places unreasonable pressure on an offeree to accept the deal on the table. Such offers typically "explode" or disappear in an unacceptably and arbitrarily short time frame. The offeror uses such techniques to preclude the offeree from considering other options, and to conclude the transaction expeditiously. This article discusses the way exploding offers work, why they are ethically questionable, and offers a technique-The Farpoint Gambit-as a means to defuse this strong-arm tactic.
THE TIME STRUCTURE OF SELF-ENFORCING AGREEMENTS

A principal and an agent enter into a sequence of agreements. The principal faces an interim participation constraint at each date, but can commit to the current agreement; in contrast, the agent has the opportunity to renege on the current agreement. We study the time structure of agreement sequences that satisfy participation and no-deviation constraints and are (constrained) efficient. We show that every such sequence must, after a finite number of dates, exhibit a continuation that maximizes the agent's payoff over all such efficient, self-enforcing sequences. Additional results are provided for situations with transferable payoffs.