cssi/SciSciGPT-SciSciNet huggingface dataset:
The effect of creep flow on two-dimensional isoflux microchannels

Microchannel convective heat transfer and friction loss characteristics are numerically evaluated for gaseous, two-dimensional, steady state, laminar, constant wall heat flux flows. The effects of Knudsen number, accommodation coefficients, second-order slip boundary conditions, creep flow, and hydrodynamically/thermally developing flow are considered. These effects are compared through the Poiseuille number and the Nusselt number. Numerical values for the Poiseuille and Nusselt numbers are obtained using a continuum based three-dimensional, unsteady, compressible computational fluid dynamics algorithm that has been modified with slip boundary conditions. To verify the numerical results, analytic solutions of the hydrodynamically and thermally fully developed momentum and energy equations have been derived subject to both first- and second-order slip velocity and temperature jump boundary conditions. The resulting velocity and temperature profiles are then utilized to obtain the microchannel Poiseuille and Nusselt numbers as a function of Knudsen number, first- and second-order velocity slip and temperature jump coefficients, Brinkman number, and the ratio of the thermal creep velocity to the mean velocity. Excellent agreement between the numerical and analytical data is demonstrated. Second-order slip terms and creep velocity are shown to have significant effects on microchannel Poiseuille and Nusselt numbers within the slip flow regime.
Graphene on hexagonal boron nitride

The field of graphene research has developed rapidly since its first isolation by mechanical exfoliation in 2004. Due to the relativistic Dirac nature of its charge carriers, graphene is both a promising material for next-generation electronic devices and a convenient low-energy testbed for intrinsically high-energy physical phenomena. Both of these research branches require the facile fabrication of clean graphene devices so as not to obscure its intrinsic physical properties. Hexagonal boron nitride has emerged as a promising substrate for graphene devices as it is insulating, atomically flat and provides a clean charge environment for the graphene. Additionally, the interaction between graphene and boron nitride provides a path for the study of new physical phenomena not present in bare graphene devices. This review focuses on recent advancements in the study of graphene on hexagonal boron nitride devices from the perspective of scanning tunneling microscopy with highlights of some important results from electrical transport measurements.
Giant planet magnetospheres

The classification of the giant planet magnetospheres into two varieties is examined: the large symmetric magnetospheres of Jupiter and Saturn and the smaller irregular ones of Uranus and Neptune. The characteristics of the plasma and the current understanding of the magnetospheric processes are considered for each planet. The energetic particle populations, radio emissions, and remote sensing of magnetospheric processes in the giant planet magneotospheres are discussed.
Motivic cell structures

An object in motivic homotopy theory is called cellular if it can be built out of motivic spheres using homotopy colimit constructions. We explore some examples and consequences of cellularity. We explain why the algebraic K-theory and algebraic cobordism spectra are both cellular, and prove some Kunneth theorems for cellular objects. AMS Classification 55U35; 14F42
Rhodium-hydroxyl bisphospholane catalyzed highly enantioselective hydrogenation of dehydroamino acids and esters

Abstract A chiral hydroxyl bisphospholane, 1,2-bis[(2 S ,3 S ,4 S ,5 S )-3,4-dihydroxyl-2,5-dimethylphospholanyl]benzene ( 4 ), was synthesized from readily available d -mannitol. Its Rh(I) complex catalyzes asymmetric hydrogenation of dehydroamino acids and their ester derivatives with excellent enantioselectivities (98 to >99% ee).
Teaching Computational Economics to Graduate Students

The teaching of computational economics to graduate students has mostly been in a single course with a focus on algorithms and computer code. The shortcoming with this approach is that it neglects one of the most important aspects of computational economics--namely model development skills. These skills are the ability to conceptualize the science, engineering and economics of a problem and to convert that understanding first to a mathematical model and then to a computational representation in a software system. Thus we recommend that a two course sequence in computational economics be created for graduate students with the first course focusing on model development skills and the second course on algorithms and the speed and accuracy of computer codes. We believe that a model development course is most helpful to graduate students when it introduces the students to a wide variety of computational models created by past generations and ask them to first make small modification in order to better understand the models, the mathematics and the software. This in turn is followed by encouraging them to make more substantial modifications of the students' own choosing so as to move the models in directions that permit the students to address current economic problems. We think that the key element of this process is it's enhancement of the creative abilities of our students.
Total synthesis of artochamins F, H, I, and J through cascade reactions

A concise and efficient cascade-based total synthesis of artochamins F, H, I, and J is described. The potential biogenetic connection between artochamin F, or a derivative thereof, and artochamins H, I, and J, through an unusual formal [2+2] cycloaddition process, was shown to be feasible. An alternative mechanism for this transformation is also proposed.
Present and Future Applications for Laser Processing of Hybrids and Semiconductors

Present and future development of laser processing as a production technique for modifying semiconductor devices, improving yields, and decreasing development times are described. Current applications covered include thick‐ and thin‐film resistor trimming, deposited film and polysilicon resistors on silicon trimming and redundant memory repair. Emerging applications include microcircuit mask making and capacitor trimming. Examples of processes still under development include selective annealing, minority‐carrier lifetime doping, and device diagnostics by laser imaging.
Quantum Weyl Algebras

Abstract Let R be a Hecke symmetry. There is then a natural quantization A n ( R ) of the n th Weyl algebra A n based on R . The aim of this paper is to study some general ring-theoretical aspects of A n ( R ) and its relation to formal deformations of A n . We also obtain further information on those quantizations obtained from some well-known Hecke symmetries.
Angiosarcoma of the breast: a rare clinicopathological entity.

Objectives:Angiosarcoma is a rare subtype of sarcoma that usually arises after radiation therapy for primary breast cancer. Primary sarcomas of the breast are rare entities and account for less than 1% of all malignant breast neoplasms. We examine our institutional experience with angiosarcomas of t
Vibration of Prestressed Periodic Lattice Structures

Equations are developed for vibration of general lattice structures that have repetitive geometry. The method of solution is an extension of a previous paper for buckling of similar structures. The theory is based on representing each member of the structure with the exact dynamic stiffness matrix and taking advantage of the repetitive geometry to obtain an eigenvalue problem involving the degrees-of-freedom at a single node in the lattice. Results are given for shell-and beam-like lattice structures and for rings stiffened with tension cables and a central mast. The variation of frequency with external loading and the effect of local member vibration on overall modes is shown.
Sequential Pd-Catalyzed Asymmetric Allene Diboration/α-Aminoallylation

Pd-catalyzed enantioselective diboration of prochiral allenes provides adducts which participate in highly selective allylation reactions with primary imines. The allylation product is a vinyl boronate which may be oxidized to give nonracemic Mannich products (87−97% ee). Alternatively, enantiomerically enriched homoallylic amine derivatives may be obtained by protonation and Suzuki cross-coupling of the vinyl boronate.
R-Groups and elliptic representations for similitude groups

The tempered spectrum of the similitude groups of non-degenerate symplectic, hermitian, or split orthogonal forms defined over $p$\snug-adic groups of characteristic zero is studied. The components of representations induced from discrete series of proper parabolic subgroups are classified in terms of $R$\snug-groups. Multiplicity one is proved. The tempered elliptic spectrum is identified, and the relation between elliptic characters appearing in a given induced representation is determined. Those irreducible tempered representations which are not elliptic and not fully induced from elliptic tempered representations are described.
A statistical approach to decision tree modeling

A statistical approach to decision tree modeling is described. In this approach, each decision in the tree is modeled parametrically as is the process by which an output is generated from an input and a sequence of decisions. The resulting model yields a likelihood measure of goodness of fit, allowing ML and MAP estimation techniques to be utilized. An efficient algorithm is presented to estimate the parameters in the tree. The model selection problem is presented and several alternative proposals are considered. A hidden Markov version of the tree is described for data sequences that have temporal dependencies.
Depyrophosphorylation of adenosine 5'-triphosphate (ATP)

Abstract The slow hydrolysis of free adenosine 5′-triphosphate (ATP) in both weakly and strongly basic aqueous solution (NaOH, 4 °C) is found to favor depyrophosphorylation over dephosphorylation. In the middle pH region (25 °C) the addition of N4Co(H2O)23+ (N4=tn2, trpn; N4Co(H2O)(OH)2+ pre-dominant species) to preformed N4CoATP− complexes (N4 = tn2, trpn, tren) results in increased rates in production of Pi, but not of PPi. However, addition of Cu2+ or Ca2+ to preformed N4CoATP− complexes (N4 = tn2, trpn, tren) leads to increased rates in the production of PPi as well as of Pi. Mechanistic implications are discussed. The production of Pi from ATP (dephosphorylation) has been monitored by quenching aliquots with Eu2+ (H+) and rapidly replacing multivalent cations with Na+ (ion exchange) before developing phosphomolybdate for analysis. The production of PPi from ATP (depyrophosphorylation ) has been monitored, following similar quenching with Eu2+ (H+) and replacement of multivalent cations, by assaying for free PPi using a coupled enzyme system.
Effects of Agriculture on Erosion and Sedimentation in the Piedmont Province, Maryland

A study of surficial deposits in the Piedmont province of Maryland has made it possible to construct a balance equation of sediment production and deposition since erosive agricultural land use began in the 1700s. Truncated Piedmont upland soil profiles imply approximately 0.15 m of soil erosion. In Western Run, a basin 155 km2, consisting of 85 percent Chester and Manor soils, this amounts to 130 × 10−3 hm3/km2 of eroded sediment. Reservoir sedimentation rates imply that 34 percent of the eroded sediment has been carried out of the system. The rest of the sediment remains in the watershed as alluvium in the upper 1 m of flood plains and as colluvium and sheetwash deposits on hillslopes. Agricultural sediment stored in flood plains constitutes 14 percent of the estimated soil erosion. The sediment was deposited mostly by overbank deposition at rates as high as 1.6 cm/yr. The remaining 52 percent of the eroded sediment occurs as colluvium and sheetwash deposits on hillslopes and as fan-shaped colluvial-alluvial deposits at junctures of headwater tributaries. Wood from such deposits was radiocarbon dated at 290 ± 100 yr. A buried junk pile in a flood plain yielded license plates whose dates imply that after 1925 the dump was buried by overbank deposition at rates as high as those for a basin undergoing urbanization. Piedmont basins less than 26 km2 have statistically longer bankfull recurrence intervals than streams with drainage areas greater than 26 km2. This suggests that since the decline of agricultural land use in the early 1900s, small upland tributaries have adjusted to decreased sediment loads by entrenchment into and erosion of sediment deposited since the initiation of colonial agricultural land use.
Pulsed Electrodeposition of Iron‐Nickel Alloys

This paper reports on the effects of dc, pulse, and pulse reverse current waveforms on deposition of Fe-Ni alloys studied in unagitated solutions and with a rotating cylindrical electrode. A nickel sulfamate/ferrous chloride electrolyte system at pH 2 less than 2 A/dm{sup 2}. Pulse reverse plating led to a decrease in anomalous deposition at low current densities. Rotating cylindrical electrodes indicated significant mass transfer effects at high current densities. During pulse reverse plating an increase in anodic pulse magnitude decreased anomalous deposition; pulse frequency had its greatest effect in reducing anomalous deposition between 100 and 300 Hz.
Machining, surface work hardening, and strength of MgO

Machining of MgO by sawing, grinding, sanding, and polishing introduces a surface layer of dense slip whose depth depends on material (e.g. yield stress and grain size) and machining parameters. Cracks, which were always more shallow than the depth of slip, extended from sawn and, to a lesser extent, from ground surfaces into single crystals and some large grains. Annealing removed the slip and decreased surface grain growth in fine-grained bodies but in general did not result in recrystallization. Surface work hardening increases hardness; it also increases bend strengths of some single crystal orientations and of larger-grained bodies, especially those with limited intragranular porosity. Fine-grained bodies were weakened by machining.
Mumford–Thaddeus Principle on the Moduli Space of Vector Bundles on an Algebraic Surface

We study the behavior of the Gieseker space of semistable torsion-free sheaves of rank r and fixed c_1, c_2 on a non-singular projective surface as the polarization varies. It is shown that the ample cone admits a locally finite chamber structure, and that passing a wall adjacent to a pair of chambers has the effect of modifying the moduli space by a (finite) sequence of flips of the type studied by Thaddeus. The key steps are a modification of Simpson's method and the introduction of a "rationally twisted" moduli space. The result is more general but less explicit than the recent work of Ellingsrud-Goettsche (alg-geom/9410005) and Friedman-Qin (alg-geom/9410007).
A Near-infrared Spectroscopic Survey of Class I Protostars

We present the results of a near-IR spectroscopic survey of 110 Class I protostars observed from 0.80 μm to 2.43 μm at a spectroscopic resolution of R = 1200. This survey is unique in its selection of targets from the whole sky, its sample size, wavelength coverage, depth, and sample selection. We find that Class I objects exhibit a wide range of lines and the continuum spectroscopic features. Eighty-five percent of Class I protostars exhibit features indicative of mass accretion, and we found that the veiling excess, CO emission, and Br γ emission are closely related. We modeled the spectra to estimate the veiling excess (rk ) and extinction to each target. We also used near-IR colors and emission line ratios, when available, to also estimate extinction. In the course of this survey, we observed the spectra of 10 FU Orionis-like objects, including 2 new ones, as well as 3 Herbig Ae-type stars among our Class I young stellar objects. We used photospheric absorption lines, when available, to estimate the spectral type of each target. Although most targets are late-type stars, there are several A- and F-type stars in our sample. Notably, we found no A or F class stars in the Taurus-Auriga or Perseus star-forming regions. There are several cases where the observed CO and/or water absorption bands are deeper than expected from the photospheric spectral type. We find a correlation between the appearance of the reflection nebula, which traces the distribution of material on very large scales, and the near-IR spectrum, which probes smaller scales. All of the FU Orionis-like objects are associated with reflection nebulae. The spectra of the components of spatially resolved protostellar binaries tend to be very similar. In particular both components tend to have similar veiling and H2 emission, inconsistent with random selection from the sample as a whole. There is a strong correlation between [Fe II] and H2 emission, supporting previous results showing that H2 emission in the spectra of young stars is usually shock excited by stellar winds.
Multiple cyclotron method to search for CP violation in the neutrino sector.

New low-cost, high-power proton cyclotrons open the opportunity for a novel precision search for $CP$ violation in the light neutrino sector. The accelerators can produce decay-at-rest neutrino beams located at multiple distances from a Gd-doped ultralarge water Cherenkov detector in order to search for $CP$ violation in ${\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}}\ensuremath{\rightarrow}{\overline{\ensuremath{\nu}}}_{e}$ oscillations at short baselines. This new type of search complements presently proposed experiments, providing measurements that could lead to a substantially better exploration of $CP$ violation in the neutrino sector.
Managerial incentives in an entrepreneurial stock market model

Abstract This paper addresses the First Theorem of Welfare Economics in a moral hazard environment. An entrepreneur sells equity in a firm which he supplies with an unobservable, costly input. How much equity he retains determines his incentives and is observed by investors. The investors have rational expectaions which cause the equity price to increase in the amount of equity the entrepreneur retains. This gives the entrepreneur an incentive to retain equity and hence supply input. The entrepreneur may also be bound by an explicit incentive contract. In this framework, not all competitive equilibria are efficient, as defined relative to the moral hazard constraint. However, equilibria can be inefficient only if the entrepreneur's optimal input is nonunique or exhibits positive income effects.
An improved protocol for azole synthesis with PEG-supported Burgess reagent

Abstract A polyethyleneglycol-linked version of Burgess reagent was developed and applied toward the cyclodehydration of β-hydroxy amides and thioamides. The desired oxazolines and thiazolines were obtained in high yields and excellent purities. The major advantages of the polymer bound reagent are its improved ease of handling and greatly increased yields in the synthesis of labile oxazolines.
HYPERTROPHIC OSTEOARTHROPATHY AND PREGNANCY

Abstract Two patients developed hypertrophic osteoarthropathy during pregnancy. Both had immediate cessation of symptoms after delivery. Periosteal new bone formation in one patient was found to ha...
Fluctuations of parabolic equations with large random potentials

In this paper, we present a fluctuation analysis of a type of parabolic equations with large, highly oscillatory, random potentials around the homogenization limit. With a Feynman–Kac representation, the Kipnis–Varadhan’s method, and a quantitative martingale central limit theorem, we derive the asymptotic distribution of the rescaled error between heterogeneous and homogenized solutions under different assumptions in dimension \(d\ge 3\). The results depend highly on whether a stationary corrector exits.
Baryogenesis constraints on the minimal supersymmetric model

Abstract The requirement that the vacuum expectation values of Higgs fields immediately after the phase transition be large enough imposes constraints upon the parameters of the minimal supersymmetric model. In particular, one obtains the upper bounds on the lighter CP-even Higgs mass and the soft supersymmetry breaking scale for different values of the top quark mass.
CP violation in B decays from anomalous tbW interactions

Abstract We calculate the effect of new CP violating interactions parameterized by an anomalous tbW coupling on CP -odd observables in B decays. We find that couplings consistent with current bounds induce observable effects in some CP asymmetries that will be measured in B -factories. The new effects are sufficiently large that they can actually test specific models that give rise to these tbW interactions.
Improved superconducting properties of MgB2

Abstract We present electrical transport, magnetization, and specific heat measurements on bulk magnesium diboride (MgB 2 ) samples ( T c =38.5 K) synthesized under 200 MPa pressure using a process based on hot isostatic pressing with cooling under pressure. The samples are fully dense and display excellent superconducting properties, including a narrow superconducting transition width ( ΔT c =0.75 K), a high upper critical field H c2 ( H c2 (0)∼152 kOe), and a critical current density J c that is the largest yet measured for bulk samples of MgB 2 ( J c (0)∼1.4 MA/cm 2 ). Specific heat measurements yielded a jump ΔC at T c of 92 mJ/mol K. These superconducting properties are comparable to those obtained with techniques that are not so well suited to industrial scale fabrication.
Copper catalyzed atom transfer radical cascade reactions in the presence of free-radical diazo initiators as reducing agents

Exceptional activity of [Cu(II)(TPMA)Cl][Cl] (TPMA = tris(2-pyridylmethyl)amine) complex in atom transfer radical addition (ATRA) of CCl(4) to 1,6-dienes followed by sequential atom transfer radical cyclization (ATRC) in the presence of free-radical diazo initiators as reducing agents is reported.
Reactions of organometallics with oximes. Synthesis of α-N-hydroxy amino acids

Abstract Reaction of organolithium reagents with glyoxylate and pyruvate derived oximes provides a direct route for the synthesis of unusual α-N-hydroxy amino acids.
The Relationship Between Economic Characteristics and Alternative Annual Earnings Persistence Measures

Accounting researchers (and potentially others) generally select rather simple, lower‐order, time‐series models to develop proxies for earnings persistence. However, measures of persistence produced by such models are not related to characteristics of the firm's economic environment that are expected to influence earnings persistence. Using a sample of 162 calendar year‐end New York Stock Exchange firms, we document the cross‐sectional relations between a set of relatively constant, firm‐specific, economic characteristics that are theoretical determinants of persistence and measures of earnings persistence derived from both lower‐order and higher‐order Autoregressive, Integrated, Moving‐Average (ARIMA) models. When lower‐order ARIMA models are used to generate measures of earnings persistence, the cross‐sectional regression models measuring the association between persistence and economic determinants of persistence yield very low adjusted R2s. In sharp contrast, when differenced, higher‐order ARIMA model...
Carbon Flashes in the Heavy-Element Ocean on Accreting Neutron Stars

We show that the burning of a small mass fraction X12 of 12C in a neutron star ocean is thermally unstable at low accumulated masses when the ocean contains heavy ashes from the hydrogen-burning rapid proton process. The key to early unstable ignition is the decreased thermal conductivity of a heavy-element ocean. The instability requires accretion rates, , in excess of 1/10 the Eddington limit when X12 < 0.1. Lower 's will stably burn a small mass fraction of 12C. The unstable flashes release ~1042-1043 ergs over hours to days and are likely the cause of the recently discovered large type I bursts (the so-called superbursts) from six Galactic low-mass X-ray binaries. In addition to explaining the energetics, recurrence times, and durations of the superbursts, these mixed 12C flashes also have an dependence of unstable burning similar to that observed. Although the instability is present at accretion rates ≈Edd, the flashes provide less of a contrast with the accretion luminosity there, thus explaining why detection is easier when ≈ (0.1-0.3)Edd.
Zeros of the partition function for higher-spin 2D Ising models

We present calculations of the complex-temperature zeros of the partition functions for 2D Ising models on the square lattice with spin s=1, 3/2 and 2. These give an insight into complex-temperature phase diagrams of these models in the thermodynamic limit. Support is adduced for a conjecture that all divergences of the magnetization occur at endpoints of arcs of zeros protruding into the FM phase. We conjecture that there are 4(s2)-2 such arcs for s>or=1, where (x) denotes the integral part of x.
Solute geochemical mass-balances and mineral weathering rates in small watersheds: Methodology, recent advances, and future directions

Abstract Solute-based geochemical mass balance methods are commonly used in small-watershed studies to estimate rates of a variety of geochemical processes at the Earth’s surface, including primary-mineral weathering and soil formation, and the quantitative contribution of these elemental transfer processes to cation budgets, nutrient cycling, and landscape susceptibility to acid deposition. Weathering rates of individual minerals in watershed mass-balance studies are determined by solving a system of simultaneous linear geochemical mass-balance equations with constant (stoichiometric) coefficients. These equations relate the measured net fluxes to the (known) stoichiometries and (unknown) rates of weathering reactions for multiple minerals in the weathering profiles. Solving the system of equations requires petrologic, mineralogic, hydrologic, botanical, and aqueous geochemical data. The number of mineral-weathering rates that can be determined is limited by the number of elements for which solute mass-balance equations can be written. In addition to calculating mineral weathering rates, elemental transfer into or out of the biomass may also be calculated. Elemental uptake by aggrading forest vegetation can act as an intrawatershed sink for at least some mineral-derived cations, producing mineral weathering rates higher than would be estimated from solute fluxes alone; similarly, element release from decaying forest biomass can result in higher solute fluxes than are produced by weathering alone. The mathematics of, significant contributions from, role of biomass in, and recent advances in, watershed geochemical mass-balance methods are discussed using examples from the Appalachian headwaters watersheds of the Coweeta Hydrologic Laboratory in the southern Blue Ridge Physiographic Province of North Carolina, USA.
Stagnation Temperature and Molecular Weight Effects in Jet Interaction

The purpose of this study was to investigate the effect of injectant stagnation temperature and molecular weight variation on the flowfield generated from secondary injection of a gas normal to a supersonic stream. Experiments were conducted at a primary stream Mach number of 2.80 in the Naval Postgraduate School supersonic wind tunnel. Experimental data have been correlated with various theories, showing both agreement and disagreement. Data presented include penetration of secondary jet into primary flow and shock shape as correlated with the second-order blast wave theory. Jet momentum, not jet mass, was found to be the main determinant of the observed jet effects.
From matrices to strings and back

We discuss an explicit construction of a string dual for the Gaussian matrix model. Starting from the matrix model and employing Strebel differentials techniques we deduce hints about the structure of the dual string. Next, following these hints a worldheet theory is constructed. The correlators in this string theory are assumed to localize on a finite set of points in the moduli space of Riemann surfaces. To each such point one associates a Feynman diagram contributing to the correlator in the dual matrix model, and thus recasts the worldsheet expression as a sum over Feynman diagrams.
Overcoming fluconazole resistance in Candida albicans clinical isolates with tetracyclic indoles.

Continuing efforts to discover novel means of combating fluconazole resistance in Candida albicans have led to the identification of an indole derivative capable of sensitizing strains demonstrating resistance to fluconazole. This tetracycle (2, ML229) does not appear to act through established Hsp90 or calcineurin pathways to chemosensitize C. albicans, as determined in S. cerevisiae models, and may be a useful probe to uncover alternative resistance pathways.
Inorganic nano-adsorbents for the removal of heavy metals and arsenic: a review

Adsorption is widely popular for removal of heavy metals due to its low cost, efficiency, and simplicity. The focus of this review will be the use of inorganic adsorbents engineered at the nanoscale. The applicability of iron oxide (hematite, magnetite and maghemite), carbon nanotubes (CNT), and metal oxide based (Ti, Zn) and polymeric nanoadsorbents are examined. The advantages and limitations of the type of nanoadsorbent and its functionality are evaluated. Current developments and next generation adsorbents are also reviewed. Finally, scopes and limitations of these adsorbents will be addressed while investigating the types of metal ions that are harmful.
Electrochemistry and spectroelectrochemistry of a linear triiron cluster

Abstract This work reports electrochemical and spectroelectrochemical studies of a unique linear triiron cluster carbonyl complex, Fe 3 (CO) 7 L 2 , where L is a α-diazothioketone. Oxidation and reduction reactions have been observed in non-aqueous media over the temperature range −40 to 20 °C by differential pulse voltammetry, cyclic voltammetry, thin-layer, UV-Vis spectroelectrochemistry and ESR spectrometry. The sequence of the individual electron-transfer steps comprising the overall redox process is described, and a comparison between the electrochemistry of different non-linear iron carbonyl complexes is discussed. A single one electron reduction produces the radical anion, [Fe 3 (CO) 7 L 2 ]-, which decomposes at temperatures greater than −10 °C to species which are reduced at a more negative potential, an ECE mechanism. A single one-electron oxidation produces the radical cation, [Fe 3 (CO) 7 L 2 ] + , which is unstable, decomposing completely at room temperature, an EC mechanism. Spectroscopic evidence indicates that in non-bonding solvents, the Fe 3 (CO) 7 L 2 framework remains intact at low temperatures for both the anion and cation radical produced electrochemically with radical stability higher than might be expected for a linear structure. Observations indicate only strongly bonding solvents disrupt the structure. Low temperature stability occurs at relatively high temperatures, with the cation radical less than stable and vulnerable to strongly bonding solvents.
The international collaborative study of maternal phenylketonuria: Status report 1998

The Maternal Phenylketonuria Study began in 1984 and during the intervening years, 572 pregnancies in hyperphenylalaninemic women and 99 controls and their outcomes have been evaluated. Among hyperphenylalaninemic women who delivered a live infant, only 15.9% were treated and in metabolic control preconceptually, however, another 18.4% were in control by 10 weeks. Compared to the results reported by Lenke and Levy in 1980, there is a marked improvement in outcome with treatment. Microcephaly was unusual in preconceptually treated pregnancies with well controlled phenylalanine restricted diets. Even in pregnancies that established control after conception but before the 8th week, congenital heart disease did not occur in the offspring, however, it did occur in 12% of pregnancies not achieving control until after 10 weeks of pregnancy. Conclusion The recommended level of blood phenylalanine during pregnancy is 120–360 μmol/l. Best results were obtained by close cooperation between the attending obstetrician and a metabolic team experienced in the care of persons with phenylketonuria.
On the facets of mixed integer programs with two integer variables and two constraints

In this paper we consider an infinite relaxation of the mixed integer linear program with two integer variables, nonnegative continuous variables and two equality constraints, and we give a complete characterization of its facets. We also derive an analogous characterization of the facets of the underlying finite integer program.
On the energy balance of solar active regions

The cause of sunspots has long been an important, unsettled problem in solar physics. Biermann1 suggested that the strong magnetic field of a sunspot inhibited convection, allowing the sunspot to cool. Parker2, on the other hand, proposed that a sunspot was cooled by the generation of waves that carried away the thermal energy. The solar ‘constant’ has been measured with a daily uncertainty of about 10 parts per million (p.p.m.) by the Active Cavity Radiometer Irradiance Monitor (ACRIM) on board the Solar Maximum Mission (SMM) satellite launched in February 1980. The ACRIM has shown that the solar constant changes with solar activity, showing dips of the order of 0.1–0.3% associated with sunspots. This discovery has provoked renewed attempts to understand the sunspot phenomenon. Two divergent views are emerging: that the missing energy is stored in the convection zone for long periods of time3 or that the missing energy is re-radiated fairly quickly at different angles by faculae4, non-spot magnetic fields that often accompany sunspots. The consequences are that in the first case an 11-yr modulation is expected in the solar output whereas in the second case it is not. I point out here that facular emission may equal the missing energy from sunspots, over a period of some weeks or months, suggesting that the missing energy is stored by being converted from kinetic into magnetic energy after which it decays back into thermal energy in the faculae.
Gallium(III)-catalyzed three-component (4+3) cycloaddition reactions.

A variety of biologically important cyclohepta[b]indole derivative is prepared via regio- and diastereoselective cycloaddition of indolyl cations with dienes.
Comparison of Baldwin-Lomax Turbulence Models for Two-Dimensional Open Cavity Computations

A study of several modified versions of the Baldwin-Lomax turbulence model applied to two-dimensional supersonic open cavity flowfields are performed. The results are clearly affected by the levels of turbulent viscosity imposed in the cavity.
X-Ray Observations of Parsec-scale Tails behind Two Middle-Aged Pulsars

Chandra and XMM-Newton resolved extremely long tails behind two middle-aged pulsars, J1509–5850 and J1740+1000. The tail of PSR J1509–5850 is discernible up to 5.6' from the pulsar, which corresponds to the projected length l⊥ = 6.5d4 pc, where d = 4d4 kpc is the distance to the pulsar. The observed tail flux is 2 × 10−13 ergs s−1 cm−2 in the 0.5-8 keV band. The tail spectrum fits an absorbed power law (PL) with the photon index Γ = 2.3 ± 0.2 and 0.5-8 keV luminosity of 1 × 1033d42 ergs s−1, for nH = 2.1 × 1022 cm−2. The tail of PSR J1740+1000 is firmly detected up to 5' (l⊥ ~ 2d1.4 pc), with a flux of 6 × 10−14 ergs cm−2 s−1 in the 0.4-10 keV band. The PL fit yields Γ = 1.4-1.5, nH ≈ 1 × 1021 cm−2, and an 0.4-10 keV luminosity of ~2 × 1031d1.42 ergs s−1. The large extent of the tails suggests that the bulk flow in the tails starts as mildly relativistic downstream of the termination shock and then gradually decelerates. Within the observed extent of the J1509–5850 tail, the average flow speed exceeds 5000 km s−1, and the equipartition magnetic field is a few × 10−5 G. For the J1740+1000 tail, the equipartition field is a factor of a few lower. For the high-latitude PSR J1740+1000, the orientation of the tail suggests that the pulsar was born from a halo-star progenitor. The X-ray efficiencies of the ram pressure-confined pulsar wind nebulae (PWNe) correlate poorly with the pulsar spin-down luminosities or ages. The efficiencies are systematically higher than those of PWNe around slowly moving pulsars with similar spin-down parameters.
Studying various optimal control problems in biodiesel production in a batch reactor under uncertainty

Abstract The optimal control problem encountered in biodiesel production can be formulated using various performance indices, namely, maximum concentration, minimum time, and maximum profit. The problems involve determining optimal temperature profile so as to maximize these performance indices. This paper presents the formulations of these optimal control problems and analyzes the solutions. Optimal control problems involve the solution of partial or second order differential equation depending on the method used, resulting in difficult tasks to solve due to their mathematical representation. This difficulty becomes more challenging when uncertainty in any parameter is considered. It has been shown that the application of maximum principle in optimal control problems provides the same results but its formulation avoids the solution of second order or partial differential equations. In this work, we use the maximum principle to solve the problems in the deterministic case. Further, we consider uncertainty in the feed composition and their effects on the optimal control solution.
Rigorous precision p-wave positron--hydrogen scattering calculation

Rigorous lower-bound p-wave positron-hydrogen phase shifts are calculated below the positronium pickup threshold. The wave function is expanded in terms of the two linearly independent D functions each multiplied by an associated Hilleraas-type radial function with two parameters. Adiabatic and nonadiabatic corrections have been included. The results are found to be larger than Armstead's (1968) in all cases near the upper edge of his estimated uncertainty.
Increased methionine-enkephalin levels in genetically epileptic (tg/tg) mice.

Abstract Recent experimental data indicate that endogenous brain ligands for the opioid receptors such as enkephalins, beta-endorphin (β-End) and dynorphin (Dyn) may be involved in both generalized and partial seizures. The “tottering” (tg/tg) mouse provides an electrophysiological representation of generalized spontaneous human epilepsy. These mice exhibit behavioral absence seizures with accompanying spike-wave discharges. Methionine-enkephalin (M-Enk), β-End and Dyn levels in various regions of brain were measured by radioimmunoassay (RIA) in 15–18-week-old tg/tg and control (+ / +) mice to elucidate the relation between seizures and the opioid system. β-End and Dyn levels were similar in tg/tg and +/+ mice. However, M-Enk levels were significantly increased in the striatum, cortex, pons and medulla of the tg/tg mice. Our data suggest that in the tottering mouse model of generalized epilepsy there is an alteration of enkephalinergic pathways and not of the endorphinergic or dynorphinergic pathways.
A New Approach for Erosion Prediction Due To Fly Ash

With increasing interest in the burning of coal in industrial gas turbines, there is also concern for the precise determination of the erosive effects on the turbine components. Series of experiments were conducted to determine the effects of fly ash constituents, particle size, particle velocity, angle of attack and target temperature on the erosion of iron and nickel base alloys. Based on the experimental results, a semi-empirical equation has been obtained for the prediction of the erosion losses. This equation provides a new technique for predicting the metal erosion due to the fly ash produced by the conventional burning of coal.Copyright © 1980 by ASME
Tin-free radical cyclization reactions initiated by visible light photoredox catalysis

Herein, we report an advancement in the application of visible light photoredox catalysts in a classic free radical mediated reaction, cyclization onto unactivated π-systems. The reactive radical intermediate is generated by the single electron reduction of an activated C–Br bond by an electron-rich redox catalyst afforded by a visible light induced catalytic cycle.
Synchronously injected amplifiers, a novel approach to high-average-power FEL

Abstract Two new FEL ideas based on synchronously injected amplifiers are described. Both of these rely on the synchronous injection of the optical signal into a high-gain, high-efficiency tapered wiggler. The first concept, called Regenerative Amplifier FEL (RAFEL), uses an optical feedback loop to provide a coherent signal at the wiggler entrance so that the optical power can reach saturation rapidly. The second idea requires the use of a uniform wiggler in the feedback loop to generate light that can be synchronously injected back into the first wiggler. The compact advanced FEL is being modified to implement the RAFEL concept. We describe future operation of the advanced FEL at high average current and discuss the possibility of generating 1 kW average power.
Competing dissociation channels in the infrared multiphoton decomposition of ethyl vinyl ether

Infrared multiphoton decomposition of ethyl vinyl ether (EVE) has been investigated by the crossed laser‐molecular beam technique. Competition is observed between the two lowest‐energy dissociation channels: (1) EVE → CH3CHO+C2H4, and (2) EVE → CH2CHO+C2H5. Center‐of‐mass product translational energy distributions were obtained for both dissociation channels. The products of reactions (1) and (2) are formed with mean translational energies of 31 and 5 kcal/mol, respectively. The branching ratio shifts dramatically in favor of the higher energy radical producing channel as the laser intensity and energy fluence are increased, in agreement with the qualitative predictions of statistical unimolecular rate theory.
Substitution in Regulatory Agencies: FDA Enforcement Alternatives

This article develops a framework to understand the factors to which regulatory agencies respond and examines how these factors may influence agency decision-making. The model shows how either changing feedback from constituents or changing regulatory costs can alter the trade-offs facing the agency and hence create opportunities for substitution among different agency actions. This framework is used to explain the changing portfolio of FDA enforcement actions between 1972-92. Results indicate that changing constituent and political feedback is the reason for the observed policy change. Specifically, budget reductions and increasing industry demand for product approval led the FDA to reduce monitoring and substitute less resource-intensive enforcement, namely recalls, for more resource-intensive enforcement. Results also show that increasing numbers of adverse drug reaction reports from consumers and physicians enabled the agency to increase the efficiency of its inspections policy and to ultimately reduce its use of inspections. Copyright 1996 by Oxford University Press.
Miliary Coccidioidomycosis in the Immunocompetent

Background Miliary coccidioidomycosis indicates hematogenous or lymphatic spread of Coccidioides immitis and is characterized by the development of multiple small granulomas throughout the lungs and other organs. Previous reports have suggested that this disorder occurs almost exclusively in immunocompromised patients, with most patients succumbing to progressive respiratory failure. In this article, we describe the largest series of immunocompetent patients with miliary coccidioidomycosis, define clinical characteristics, and outline important aspects of diagnosis and treatment. Materials and methods We identified eight patients (five men and three women; age range, 23 to 65 years) with miliary coccidioidomycosis diagnosed at Kern Medical Center (located in an endemic area) from 1990 to 1997. Four of the patients were white, two were African American, and two were Hispanic. A miliary pattern was defined as the presence of discrete 2- to 10-mm lesions diffusely distributed throughout both lung fields, as shown on chest radiograph. Microscopic examination and culture of C immitis from sputum, tissue, or body fluid confirmed diagnosis. Patients with HIV were excluded. Results These patients constituted approximately 1% of those admitted to our institution for coccidioidomycosis from 1990 to 1997. Four patients had symptoms for ≤ 1 week before admission (acute), and four had symptoms for between 5 and 12 weeks (chronic). Four patients demonstrated a miliary pattern on initial chest radiograph, and two of these patients received an initial diagnosis of miliary coccidioidomycosis. Five patients required mechanical ventilation. Arterial blood gas measurements revealed a mean Po 2 of 54.2 ± 8.6 mm Hg and a mean Pco 2 of 32.5 ± 3.2 mm Hg. Five patients developed ARDS. Five patients had extrapulmonary involvement, with the meninges (n = 4) and skin (n = 4) being the most common sites. All patients were treated with fluconazole and/or amphotericin B. Three patients died; all had chronic involvement and received mechanical ventilation. Conclusion We present eight immunocompetent patients with a lower mortality rate and better outcome than previously reported. In our series, miliary coccidioidomycosis manifested as either an acute respiratory illness or an advanced stage of a chronic illness occurring in the context of widespread dissemination. All who died had chronic involvement. Prompt recognition of miliary coccidioidomycosis is crucial, but may be hindered by the large differential diagnosis. Important diagnostic factors include a history of travel through endemic areas, ethnicity, immunologic status, involvement of multiple organ sites, and pronounced hypoxemia not accounted for by the degree of pulmonary involvement seen on chest radiograph.
Spontaneous generation of pure ice streams via flow instability: Role of longitudinal shear stresses and subglacial till

[1] A significant portion of the ice discharge in ice sheets is drained through ice streams, with subglacial sediment (till) acting as a lubricant. The known importance of horizontal friction in shear margins to ice stream dynamics suggests a critical role of longitudinal stresses. The effects of subglacial till and longitudinal stresses on the stability of an ice sheet flow are studied by linear stability analysis of an idealized ice-till model in two horizontal dimensions. A power law-viscous constitutive relation is used, explicitly including longitudinal shear stresses. The till, which has compressible viscous rheology, affects the ice flow through bottom friction. We examine the possibility that pure ice streams develop via a spontaneous instability of ice flow. We demonstrate that this model can be made intrinsically unstable for a seemingly relevant range of parameters and that the wavelengths and growth rates that correspond to the most unstable modes are in rough agreement with observed pure ice streams. Instabilities occur owing to basal friction and meltwater production at the ice-till interface. The most unstable wavelength arise because of selective dissipation of both short and long perturbation scales. Longitudinal stress gradients stabilize short transverse wavelengths, while Nye diffusion stabilizes long transverse wavelengths. The selection of an intermediate unstable wavelength occurs, however, only for certain parameter and perturbation structure choices. These results do not change qualitatively for a Newtonian ice flow law, indicating no significant role to shear thinning, although this may very well be due to the restrictive assumptions of the model and analysis.