cssi/SciSciGPT-SciSciNet huggingface dataset:
A Tidally Disrupted Asteroid around the White Dwarf G29-38

The infrared excess around the white dwarf G29-38 can be explained by emission from an opaque flat ring of dust with an inner radius of 0.14 R☉ and an outer radius of less than 1 R☉. This ring lies within the Roche region of the white dwarf where an asteroid could have been tidally destroyed, producing a system reminiscent of Saturn's rings. Accretion onto the white dwarf from this circumstellar dust can explain the observed calcium abundance in the atmosphere of G29-38. Either as a bombardment by a series of asteroids or because of one large disruption, the total amount of matter accreted onto the white dwarf may have been ~4 × 1024 g, comparable to the total mass of asteroids in the solar system, or, equivalently, about 1% of the mass in the asteroid belt around the main-sequence star ζ Lep.
A CHANDRA OBSERVATION OF THE TW HYDRAE ASSOCIATION BROWN DWARF 2MASSW J1139511−315921

We report on a sequence of Chandra X-Ray Observatory observations of the TW Hydrae brown dwarf (BD) 2MASSW J1139511-315921 (2M1139). In the combined 31 ks ACIS-S exposure, 2M1139 is detected at the 3{sigma} confidence level. We find an X-ray luminosity of L{sub X} = 1.4{sup +2.7}{sub -1.0} x 10{sup 26} erg s{sup -1} or log L{sub X}/L{sub bol} = -4.8 {+-} 0.3. This object is similar to another TW Hydrae BD member, CD-33 7795B (TWA 5B): both have H{alpha} emission, both show no signatures of accretion, and both have comparable ages and spectral types. TWA 5B was previously detected in X-rays with a luminosity of L{sub X} = 4 x 10{sup 27} erg s{sup -1} or log L{sub X}/L{sub bol} = -3.4, an order of magnitude more luminous in X-rays than 2M1139. We find that the discrepancy between the X-ray luminosity of 2M1139 and TWA 5B is consistent with the spread in X-ray luminosity in the Orion Nebula Cluster for BDs of similar spectral types. Though rotation may play a role in the X-ray activity of ultracool dwarfs like 2M1139 and TWA 5B, the discrepancy cannot be explained by rotation alone. We also examine two X-ray bright objects in themore » field of view of our Chandra observations and find one to be of spectral type K0IV and identify it as a possible RS Canum Venaticorum, and another X-ray bright object whose light curve clearly shows the decay phase of an X-ray flare.« less
Nature of expertise in searching mammograms for breast masses

Rationale and Objectives. The authors investigated how training and experience affect the performance of observers searching mammograms for breast masses. Methods. Eye positions of mammographers, mammography technologists, mammography residents, and laypersons were compared to scan paths generated by a simulated scanner as each searched nine two-view digital mammogram pairs for breast masses. Results. Analysis of time-to-hit data revealed that mammographers and mammography technologists with the most extensive training and experience had the fastest search times in the detection and confirmation of a breast mass on two views. Scanning patterns of less-experienced mammography residents were less efficient due to wider dispersion of visual attention between potential breast masses and perturbations in breast parenchyma. Because laypersons lacked both training and experience in mammography, bright blobs in the breast image were considered to be intuitively valid target candidates and these features distracted the search by capturing visual attention. Conclusion. Experience reading normal and abnormal mammograms plays a critical role in training radiologists. Experience combined with training provides the basis for generating efficient visual search strategies and developing distinctive conceptual criteria for perceptual differentiation and interpretation of true breast masses from image artifacts and structured noise that mimics breast abnormalities.
A review of pharmacologic management and prevention strategies for delirium in the intensive care unit.

Background The prevalence of delirium has been estimated at anywhere between 10% and 30% in general medical patients and in upwards of 80% in patients who are admitted to an intensive care unit (ICU). Given the high prevalence of delirium in the ICU population, it should not be surprising that a large percentage of psychiatric consults arise from this setting. While the mainstay of pharmacologic management of delirium centers on neuroleptic medications, such as haloperidol, recent studies using alternate agents have shown varying levels of promise. Objective Our purpose is to outline the major prospective studies looking at the efficacy of pharmacologic management and prevention strategies for delirium exclusively in adult ICU patients. Both conventional and novel pharmacotherapeutic interventions are discussed. Method Articles were obtained using the MEDLINE/PUBMED database looking specifically at pharmacologic interventions for delirium in the intensive care unit. A search was performed using the key words"delirium," "intensive care unit," "treatment," and "prophylaxis." The authors limited their search to prospective studies, specifically randomized trials (both placebo-controlled and non-controlled) in the adult ICU population, and eliminated retrospective and observational studies. Relevant citations from the previously mentioned articles were also included in the review. Conclusion There is a plethora of studies on pharmacologic management strategies in general medical patients with delirium. Findings from these studies are often extrapolated to the ICU population; however, when looking at studies limited to ICU patients with delirium, there are far fewer credible prospective studies.
Electrochemical properties of natural organic matter (NOM), fractions of NOM, and model biogeochemical electron shuttles.

In this study, cyclic voltammetry was used to characterize the redox properties of natural organic matter (NOM). Using a stationary platinum working electrode, minimal concentrations of electrolyte, and dimethyl sulfoxide (DMSO) as the solvent, we were able to resolve two pairs of oxidation and reduction peaks for a fraction of Georgetown NOM that is enriched in polyphenolic moieties (NOM-PP). Applying our method to other fractions of Georgetown NOM, and to samples of NOM from a wide range of other sources, gave cyclic voltammograms (CVs) that generally contained fewer distinguishing features than those obtained with NOM-PP. For comparison, CVs were also obtained using our method on six quinone model compounds: anthraquinone-2,6-disulfonate (AQDS), lawsone, juglone, menadione, menaquinone-4, and ubiquinone-5. The CVs of these quinones were similar in shape to the CV of NOM-PP, consistent with the notion that quinones are the dominant redox-active moieties associated with NOM. Quantitative analysis of the...
Land use in a circular city

Abstract This paper is concerned with optimal allocation of urban land to transportation. It attempts to extend the work of Solow and Vickrey, who posed this problem in an operationally one-dimensional long narrow city, to a two-dimensional circular city with a network of radial and circumferential roads. An interesting new problem arises, namely that travelers now have a choice of routes. Rules for optimal resource allocation are developed and analyzed. Assuming travel costs to be a strictly convex function of traffic density, it is shown that there is no travel through the center of an optimal city.
The Optimal Mix of Inflationary Finance and Commodity Taxation with Collection Lags

When there are collection lags in the tax system, inflation reduces real revenues. This is often offered as an argument for less reliance on the inflation tax. But the optimal rates of other taxes should also be reconsidered in the light of collection lags. When this is done, the focus shifts from the revenues (which can be recouped by changing the rates of these taxes) to the associated costs of collection. In a benchmark case where the average costs of collection are constant, the optimal inflation tax is independent of the collection lag.
Bootstrap-based critical values for the information matrix test

Abstract In finite samples, the true size of White's information matrix test often differs greatly from its nominal size based on asymptotic critical values. This paper shows how the bootstrap can be used to obtain improved finite-sample critical values. The results of Monte Carlo experiments show that for the cases investigated, the bootstrap largely eliminates the problem of incorrect finite-sample size. Moreover, when size-corrected critical values are used, forms of the test that have small size distortions with asymptotic critical values can have much lower power than forms that have large size distortions with asymptotic critical values.
Decreasing airline delay propagation by re-allocating scheduled slack

Passenger airline delays have received increasing attention over the past several years as air space congestion, severe weather, mechanical problems, and other sources cause substantial disruptions to a planned flight schedule. Adding to this challenge is the fact that each flight delay can propagate to disrupt subsequent downstream flights that await the delayed flight's aircraft and crew. This potential for delays to propagate is exacerbated by a fundamental conflict: slack in the planned schedule is often viewed as undesirable, as it implies missed opportunities to utilize costly perishable resources, whereas slack is critical in operations as a means for absorbing disruption. This article shows how delay propagation can be reduced by redistributing existing slack in the planning process, making minor modifications to the flight schedule while leaving the original fleeting and crew scheduling decisions unchanged. Computational results based on data from a major U.S. carrier are presented that show that...
Putting Statistics into the Statistical Energy Analysis of Automotive Vehicles

Sound and vibration transmission modeling methods are important to the design process for high quality automotive vehicles. Statistical Energy Analysis (SEA) is an emerging design tool for the automotive industry that was initially developed in the 1960's to estimate root-mean-square sound and vibration levels in structures and interior spaces. Although developed to estimate statistical mean values, automotive design application of SEA needs the additional ability to predict statistical variances of the predicted mean values of sound and vibration. This analytical ability would allow analysis of vehicle sound and vibration response sensitivity to changes in vehicle design specifications and their statistical distributions. This paper will present an algorithm to extend the design application of the SEA method through prediction of the variances of RMS. responses of vibro-acoustic automobile structures and interior spaces from variances in SEA automotive model physical parameters. The variance analysis is applied to both a simple, complete illustrative example and a more complex automotive vehicle example. Example variance results are verified through comparison with a Monte Carlo test of 2,000 SEA responses whose physical parameters were given Gaussian distributions with means at design values. Analytical predictions of the response statistics agree with the statistics generated by the Monte Carlo method but only require about 1/300 of the computational effort.
An empirical study of the robustness of MacOS applications using random testing

We report on the fourth in a series of studies on the reliability of application programs in the face of random input. Over the previous 15 years, we have studied the reliability of UNIX command line and X-Window based (GUI) applications and Windows applications. In this study, we apply our fuzz testing techniques to applications running on the Mac OS X operating system. We continue to use a simple, or even simplistic technique: unstructured black-box random testing, considering a failure to be a crash or hang. As in the previous three studies, the technique is crude but seems to be effective in locating bugs in real programs.We tested the reliability of 135 command-line UNIX utilities and thirty graphical applications on Mac OS X by feeding random input to each. We report on application failures - crashes (dumps core) or hangs (loops indefinitely) - and, where source code is available, we identify the causes of these failures and categorize them.Our testing crashed only 7% of the command-line utilities, a considerably lower rate of failure than observed in almost all cases of previous studies. We found the GUI-based applications to be less reliable: of the thirty that we tested, only eight did not crash or hang. Twenty others crashed, and two hung. These GUI results were noticeably worse than either of the previous Windows (Win32) or UNIX (X-Windows) studies.
N-methyl lithiation of N-methylindoles directed by α-amino alkoxides

Abstract A novel N-methyl lithiation-alkylation of an α-amino alkoxide derived from 3-chloro-N-methylindole-2-carboxaldehyde is described.
Enantiospecific synthesis of the proposed structure of the antitubercular marine diterpenoid pseudopteroxazole: revision of stereochemistry.

An enantiospecific synthesis of structure 1, previously assigned to the antitubercular marine natural product pseudopteroxazole, has been accomplished as outlined in Scheme 1. Coupling of diene acid 3 and amino phenol 4 produced the amide 5, which was subjected to a novel oxidative intramolecular Diels−Alder reaction to generate the tricyclic lactam 6a stereoselectively. This product was transformed via intermediates 7−11 into the diene 13. Cationic cyclization of 13 afforded two diastereomeric tricyclic amphilectanes which were separated and transformed by parallel four-step sequences into 1 and 2, respectively. Neither 1 nor 2 were identical with pseudopteroxazole, indicating a need for revision of the structure, probably to 16.
Non-Newtonian gravity or gravity anomalies?

Geophysical measurements of G differ from laboratory values, indicating that gravity may be non-Newtonian. A spherical harmonic formulation is presented for the variation of (Newtonian) gravity inside the Earth. Using the GEM-10B Earth Gravitational Field Model, it is shown that long-wavelength gravity anomalies, if not corrected, may masquerade as non-Newtonian gravity by providing significant influences on experimental observation of delta g/delta r and G. An apparent contradiction in other studies is also resolved: i.e., local densities appear in equations when average densities of layers seem to be called for.
Multigrid Navier-Stokes Calculations for Three-Dimensional Cascades

A vertex-based finite volume method for solving the three-dimensional compressible Reynolds-averaged Navier-Stokes equations is presented for calculating turbomachinery cascade flows. A discretization scheme for the viscous terms is proposed. The Baldwin-Lomax algebraic turbulence model is used. The scheme is verified against laminar and turbulent flows over a flat plate. Two- and three-dimensional computations were carried out for a low-pressure turbine cascade at design and off-design conditions. Results are compared with inviscid solutions and experimental data.
Variability in Proto-planetary Nebulae. I. Light Curve Studies of 12 Carbon-rich Objects

We have carried out long-term (14 years) V and R photometric monitoring of 12 carbon-rich proto-planetary nebulae. The light and color curves display variability in all of them. The light curves are complex and suggest multiple periods, changing periods, and/or changing amplitudes, which are attributed to pulsation. A dominant period has been determined for each and found to be in the range of ~150 days for the coolest (G8) to 35-40 days for the warmest (F3). A clear, linear inverse relationship has been found in the sample between the pulsation period and the effective temperature and also an inverse relationship between the amplitude of light variation and the effective temperature. These are consistent with the expectation for a pulsating post-asymptotic giant branch (post-AGB) star evolving toward higher temperature at constant luminosity. The published spectral energy distributions and mid-infrared images show these objects to have cool (200 K), detached dust shells and published models imply that intensive mass loss ended 400-2000 years ago. The detection of periods as long as 150 days in these requires a revision in the published post-AGB evolution models that couple the pulsation period to the mass loss rate and that assume that intensive mass loss ended when the pulsation period had decreased to 100 days. This revision will have the effect of extending the timescale for the early phases of post-AGB evolution. It appears that real time evolution in the pulsation periods of individual objects may be detectable on the timescale of two or three decades.
The social responsibility of engineers and scientists

Recently there has been some interest in the question of the social responsibility of engineers. A series of articles and letters to the editor appeared in the early part of 1958 in Computers and Automation which dealt first with whether a journal such as Computers and Automation should publish articles on the social responsibility of computer scientists. Then specific topics such as the possibility of the destruction of civilization due to some component failure in the computer linked to a missile-warning radar network were treated. A series of viewpoints has been presented ranging from conscientious objection to working on a computer system that might be used for destructive purposes at one end of the scale, to a viewpoint of no concern with the use of one's work at the other end. My interpretation of these discussions is that people are arguing about the implied hypothesis: there is a danger to the existence of our civilization because social institutions have too long a time lag in making adjustments to utilize the latest technological advances wisely.
Strength of Hot Isostatically Pressed Si3N4 After Heat Treatment in Ar-O2 and H2-H2O

The effects of heat treatment in Ar-O{sub 2} and H{sub 2}-H{sub 2}O atmospheres on the flexural strength of hot isostatically pressed Si{sub 3}N{sub 4} were investigated. Increases in room-temperature strength, to values significantly above that of the aspolished material, were observed when the Si{sub 3}N{sub 4} was exposed at 1400{degrees}C to (1) H{sub 2} with water vapor pressure (P{sub H{sub 2}O}) greater than 1 {times} 10{sup {minus}4} MPa or (2) Ar with oxygen partial pressure (P{sub 02}) of between 7x{sup {minus}6} and 1.5 {times} 10{sup {minus}5} MPa. However, the strength of the material was degraded when the P{sub H{sub 2}O} in H{sub 2} was lower than 1 {times} 10{sup {minus}4} ZMPa, and essentially unaffected when the P{sub 02} in Ar was higher than 1.5 {times} 10{sup {minus}5} MPa. The authors suggest that the observed strength increases are the result of strength-limiting surface flaws being healed by a Y{sub 2}Si{sub 2}O{sub 7} layer formed during exposure.
Modeling of Mode Transition Behavior in Argon Microhollow Cathode Discharges

A self-consistent, non-equilibrium plasma discharge model is used to describe physical mechanisms and understand different operating regimes of a MHCD. The model includes a surface-electric-field dependent secondary electron coefficient description which is essential for the prediction of the different regimes of MHCD operation. At low current (<0.1 mA), the plasma is confined within the cylindrical hollow region of the discharge. At currents above a certain threshold, the discharge expands over the outer flat surface of the cathode. Transient relaxation oscillations (self-pulsing) of the discharge properties are predicted by the model for intermediate discharge currents ranging from about 0.1 to 0.3 mA.
Fate of petroleum hydrocarbons and toxic organics in Louisiana coastal environments

Numerous potentially toxic compounds are entering Louisiana’s inshore and nearshore coastal environments. To a large degree there is insufficient information for predicting the fate and effect of these materials in aquatic environments. Studies documenting the impact of petroleum hydrocarbons entering Louisiana coastal wetlands are summarized. Also included are research findings on factors affecting the persistence of petroleum hydrocarbons and other toxic organics (pentachlorophenol (PCP), 2,4-dichlorophenoxyacetic acid (2,4-D), creosote, etc.) in sediment-water systems. Sediment pH and redox conditions have been found to play an important role in the microbial degradation of toxic organics. Most of the hydrocarbons investigated degrade more rapidly under high redox (aerobic) conditions although there are exceptions (e.g., 1,1,1-trichloro-2,2-bis(4-chlorophenyl) (DDT) and polychlorobiphenyls (PCBs)). Some of these compounds, due to their slow degradation in anaerobic sediment, may persist in the system for decades.
Multidimensional on-line screening for ligands to the α3β4 neuronal nicotinic acetylcholine receptor using an immobilized nicotinic receptor liquid chromatographic stationary phase

The alpha3beta4 subtype of the neuronal nicotinic acetylcholine receptor (nAChR) subtype was immobilized on a liquid chromatographic support and the resulting column used for the rapid and direct on-line screening for nAChR ligands. A multidimensional chromatographic system was developed consisting of the immobilized receptor column (NR column) connected via a switching valve to a C(18) column that was, in turn, connected to a single quadrupole mass spectrometer. A mixture of 18 compounds, containing alpha3beta4 nAChR (7) and compounds that are not alpha3beta4 nAChR ligands (11), was injected onto the NR column. The mobile phase consisted of ammonium acetate (10 mM, pH 7.4)-methanol (95:5, v/v) and the flow-rate was 0.2 ml/min. For the first 8 min the eluent was directed to waste. At t=8 min, the switching valve was rotated and the NR column connected to the C(18) column. The eluent from the NR column was directed to the C(18) column for 12 min. At t=20 min, the switching valve was rotated and the NR column was disconnected from the C(18) column. The compounds trapped on the C(18) column were separated and eluted onto the mass spectrometer using a mobile phase of ammonium acetate (10 mM, pH 7.4)-methanol (40:60, v/v) at a flow-rate of 1.0 ml/min. Detection was accomplished using total ion monitoring. The multidimensional system correctly isolated six of the seven alpha3beta4 nAChR ligands and only one of the 11 non-ligands was found with the alpha3beta4 nAChR ligands. The results indicate that the multidimensional liquid chromatographic system can be used for the on-line screening of chemical mixtures for alpha3beta4 nAChR ligands.
The asymptotic lift of a completely positive map

Starting with a unit-preserving normal completely positive map L:M→M acting on a von Neumann algebra—or more generally a dual operator system—we show that there is a unique reversible system α:N→N (i.e., a complete order automorphism α of a dual operator system N) that captures all of the asymptotic behavior of L, called the asymptotic lift of L. This provides a noncommutative generalization of the Frobenius theorems that describe the asymptotic behavior of the sequence of powers of a stochastic n×n matrix. In cases where M is a von Neumann algebra, the asymptotic lift is shown to be a W∗-dynamical system (N,Z), and we identify (N,Z) as the tail flow of the minimal dilation of L. We are also able to identify the Poisson boundary of L as the fixed algebra Nα. In general, we show the action of the asymptotic lift is trivial iff L is slowly oscillating in the sense that limn→∞‖ρ○Ln+1−ρ○Ln‖=0,ρ∈M∗. Hence α is often a nontrivial automorphism of N. The asymptotic lift of a variety of examples is calculated.
Multispace and multilevel BDDC

The Balancing Domain Decomposition by Constraints (BDDC) method is the most advanced method from the Balancing family of iterative substructuring methods for the solution of large systems of linear algebraic equations arising from discretization of elliptic boundary value problems. In the case of many substructures, solving the coarse problem exactly becomes a bottleneck. Since the coarse problem in BDDC has the same structure as the original problem, it is straightforward to apply the BDDC method recursively to solve the coarse problem only approximately. In this paper, we formulate a new family of abstract Multispace BDDC methods and give condition number bounds from the abstract additive Schwarz preconditioning theory. The Multilevel BDDC is then treated as a special case of the Multispace BDDC and abstract multilevel condition number bounds are given. The abstract bounds yield polylogarithmic condition number bounds for an arbitrary fixed number of levels and scalar elliptic problems discretized by finite elements in two and three spatial dimensions. Numerical experiments confirm the theory.
PREPARATION OF BASE-DEUTERATED 2′-DEOXYADENOSINE NUCLEOSIDES AND THEIR SITE-SPECIFIC INCORPORATION INTO DNA

We report a four-step synthesis of 2'-deoxy-2-deuteroadenosine from 2'-deoxyadenosine in 38% overall yield. The more accessible 2'-deoxy-8-deuteroadenosine was also prepared and incorporated into DNA by automated solid phase synthesis (80% deuterium) using N6-benzoyl-2'-deoxy-8-deuteroadenosine-3'-O-(2-cyanoethyl-N,N-diisopropylphosphoramidite) in combination with acetyl-protected deoxycytidine and phenoxyacetyl-protected purine phosphoramidites.
Organic semiconductors in potentiometric gas sensors

Solid-state potentiometric sensors based on the chemical modulation of the work function of organic semiconductors are discussed. The theory of the chemical work function modulation is briefly reviewed. There are several sensor configurations, in which this transduction principle can be employed. First is the Kelvin probe, second is the chemically sensitive field-effect transistor in which the conventional metal gate of the silicon-based transistor has been replaced by an organic semiconductor. Chemical modulation of work function enters also into the operation of the third type of sensor discussed in this review, on “organic field-effect transistor”. It is shown that in reality such sensors are “field-modulated chemiresistors”, rather than potentiometric sensors.
Effect of Renal Shock Wave Lithotripsy on the Development of Metabolic Syndrome in a Juvenile Swine Model: A Pilot Study

Purpose: We performed a pilot study to assess whether renal shock wave lithotripsy influences metabolic syndrome onset and severity.Materials and Methods: Three-month-old juvenile female Ossabaw miniature pigs were treated with shock wave lithotripsy (2,000 shock waves at 24 kV with 120 shock waves per minute in 2) or sham shock wave lithotripsy (no shock waves in 2). Shock waves were targeted to the upper pole of the left kidney to model treatment that would also expose the pancreatic tail to shock waves. Pigs were then instrumented to directly measure arterial blood pressure via an implanted radiotelemetry device. They later received a hypercaloric atherogenic diet for about 7 months. Metabolic syndrome development was assessed by the intravenous glucose tolerance test.Results: Metabolic syndrome progression and severity were similar in the sham treated and lithotripsy groups. The only exception arterial blood pressure, which remained relatively constant in sham treated pigs but began to increase at abo...
Mycotic Renal Artery Degeneration and Systemic Sepsis Caused by Infected Renal Artery Stent

Abstract A case of Staphylococcus aureus renal artery stent infection was studied. Fourteen days after the procedure, the patient had a fever, hypotension, and an elevated white blood cell (WBC) count. Blood cultures were positive for S aureus on admission and during the patient's hospitalization, despite intravenous vancomycin therapy. Evaluation included serial CT scans, revealing increasing persistent inflammation with development of multiple renal intraparenchymal abscesses, and arteriography, showing marked degeneration of the renal artery. Therapy required resection of the renal artery/stent and nephrectomy. This case confirms the severe nature of S aureus stent infection; we recommend prophylactic antibiotics before these procedures, as well as expeditious evaluation and consideration for aggressive surgical therapy if this complication is suspected. (J Vasc Surg 1998;28:547-50.)
Spillovers, Foreign Investment, and Export Behavior

Abstract Case studies of export behavior suggest that firms that penetrate foreign markets reduce entry costs for other potential exporters, either through learning effects or establishing commercial linkages. We examine whether spillovers associated with one firm's export activity reduce the cost of exporting for other firms. We identify two sources of spillovers: export production in general and the specific activities of multinationals. From a simple model of export behavior we derive a probit specification for the probability that a firm exports. Using panel data on Mexican manufacturing plants, we find evidence of spillovers from multinational enterprises but not from general export activity.
Demonstration of ATP-Dependent, Ubiquitin-Conjugating Activities in Higher Plants

Ubiquitin is a highly conserved, 76-amino acid polypeptide with several important regulatory functions in both plants and animals that all arise from its covalent ligation to other cellular proteins. Here, we demonstrate that higher plants have the capacity to conjugate ubiquitin to other plant proteins in vitro. Using 125 I-labeled human ubiquitin as a substrate, conjugating activities were observed in crude etiolated tissue extracts from all species tested, including oats, rye, barley, corn, zucchini squash, pea, soybean, and sunflower. The reaction has a soluble distribution, is specific for ATP, and requires the protease inhibitor, leupeptin, to protect ubiquitin from inactivation during the assay. Conjugation is inhibited by N -ethylmaleimide and high concentrations of 2-mercaptoethanol suggesting that the mechanism of ubiquitin ligation in plants involves a similar thiolester intermediate to that found in the mammalian pathway. The conjugating activity in etiolated oat extracts is extremely labile with a half-life of about 20 minutes at 30°C. Detectable but low ATP-stimulated, conjugating activities were also observed in extracts from dry seeds and green leaves of oats. In addition to this conjugating activity, crude plant extracts have the capacity to degrade ubiquitin-protein conjugates formed in vitro. These results demonstrate that higher plants contain several of the enzymic activities necessary for ubiquitin9s functions and provide a method for assaying ubiquitin conjugation in vitro.
Convective heating in regions of large favorable pressure gradient.

Convective heating in shoulder regions of flat- faced cylinder with large favorable pressure gradient
Matrix string interactions

Abstract String configurations have been identified in compactified Matrix theory at vanishing string coupling. We show qualitatively how the interactions of these strings are determined by the Yang-Mills gauge field on the worldsheet. At finite string coupling, this suggests the underlying dynamics is not well-approximated as a theory of strings. This may explain why string perturbation theory diverges badly, while Matrix string perturbation theory presumably has a perturbative expansion with properties similar to the strong coupling expansion of 2d Yang-Mills theory.
Mission Concept for the Single Aperture Far-Infrared (SAFIR) Observatory

We have developed a preliminary but comprehensive mission concept for SAFIR, as a 10 m-class far-infrared and submillimeter observatory that would begin development later in this decade to meet the needs outlined above. Its operating temperature ( or approx. 40 microns. This would provide a point source sensitivity improvement of several orders of magnitude over that of the Spitzer Space Telescope (previously SIRTF) or the Herschel Space Observatory. Additionally, it would have an angular resolution 12 times finer than that of Spitzer and three times finer than Herschel. This sensitivity and angular resolution are necessary to perform imaging and spectroscopic studies of individual galaxies in the early universe. We have considered many aspects of the SAFIR mission, including the telescope technology (optical design, materials, and packaging), detector needs and technologies, cooling method and required technology developments, attitude and pointing, power systems, launch vehicle, and mission operations. The most challenging requirements for this mission are operating temperature and aperture size of the telescope, and the development of detector arrays. SAFIR can take advantage of much of the technology under development for JWST, but with much less stringent requirements on optical accuracy.
Rotating Black Droplet

We construct the gravitational dual, in the Unruh state, of the "jammed" phase of a CFT at strong coupling and infinite N on a fixed five-dimensional rotating Myers-Perry black hole with equal angular momenta. When the angular momenta are all zero, the solution corresponds to the five-dimensional generalization of the solution first studied in (1). In the extremal limit, when the angular momenta of the Myers-Perry black hole are maximum, the Unruh, Boulware and Hartle-Hawking states degenerate. We give a detailed analysis of the corresponding holographic stress energy tensor for all values of the angular momenta, finding it to be regular at the horizon in all cases. We compare our results with existent literature on thermal states of free field theories on black hole backgrounds.
On Destabilizing Divergences in Supergravity Models

Abstract We show that, for standard N = 1 supergravity coupled to chiral matter, if the Kahler potential has no terms linear in chiral superfields, then none are generated through quadratically divergent one-loop corrections. This holds whether or not the Kahler potential contains terms cubic in chiral (and antichiral) matter superfields. If however the cosmological constant vanishes and SUSY is spontaneously broken, linear terms are present and new quadratically divergent linear terms may be generated due to the presence of nonvanishing Kahler curvature. These can potentially destabilize the weak-scale hierarchy. We discuss the importance of this for effective supergravity models which contain standard model singlets.
FIRE, a next step option for magnetic fusion

Abstract The next major frontier in magnetic fusion physics is to explore and understand the strong non-linear coupling among confinement, MHD stability, self-heating, edge physics and wave-particle interactions that is fundamental to fusion plasma behavior. The Fusion Ignition Research Experiment (FIRE) design study has been undertaken to define the lowest cost facility to attain, explore, understand and optimize magnetically confined fusion-dominated plasmas. FIRE is envisioned as an extension of the existing advanced tokamak (AT) program that could lead to an attractive magnetic fusion reactor. FIRE activities have focused on the physics and engineering assessment of a compact, high-field tokamak with the capability of achieving Q≈10 in the Elmy H-mode for a duration of ∼1.5 plasma current redistribution times (skin times) during an initial burning plasma science phase, and the flexibility to add AT hardware (e.g. lower hybrid current drive) later. The configuration chosen for FIRE is similar to that of ARIES-RS, the US Fusion Power Plant study utilizing an AT reactor. The key ‘AT’ features are: strong plasma shaping, double null pumping divertors, low toroidal field (TF) ripple ( 5) for a duration of one to three current redistribution times.
Contact fiber bundles

Abstract We define contact fiber bundles and investigate conditions for the existence of contact structures on the total space of such a bundle. The results are analogous to minimal coupling in symplectic geometry. The two applications are construction of K -contact manifolds generalizing Yamazaki’s fiber join construction and a cross-section theorem for contact moment maps.
Combined Satellite and Ground-Based Observations of the Quiescent, High Latitude Symbiotic Variable AG Draconis = BD+67°922

Satellite observations, from Einstein, IUE, and IRAS, have been combined with ground-based observations to derive the quiescent energy distribution of the symbiotic star AG Draconis. A detailed comparison is made between the combined observations and various steady-state composite models, including blackbody accretion disks.
Steady state analysis of balanced-allocation routing

We compare the long-term, steady-state performance of a variant of the standard Dynamic Alternative Routing (DAR) technique commonly used in telephone and ATM networks, to the performance of a path-selection algorithm based on the “balanced-allocation” principle [Y. Azer, A. Z. Broder, A. R. Karlin, and E. Upfal, SIAM J Comput 29(1) (2000), 180–200; M. Mitzenmacher, Ph.D. Thesis, University of California, Berkeley, August 1996]; we refer to this new algorithm as the Balanced Dynamic Alternative Routing (BDAR) algorithm. While DAR checks alternative routes sequentially until available bandwidth is found, the BDAR algorithm compares and chooses the best among a small number of alternatives. We show that, at the expense of a minor increase in routing overhead, the BDAR algorithm gives a substantial improvement in network performance, in terms both of network congestion and of bandwidth requirement. © 2005 Wiley Periodicals, Inc. Random Struct. Alg., 2005
Comparative Statistical Analysis of Test Parts Manufactured in Production Environments

Estimating error uncertainties arising in production parts is not a well-understood process. An approach to estimate these uncertainties was developed in this study. Machine tool error components were measured on a three-axis vertical machining center. Multiple parts were produced on the measured machining center then measured on a coordinate measuring machine. Uncertainty models for hole-center to hole-center lengths and orthogonalities were developed using measured machine tool errors. These estimated uncertainties were compared against measured uncertainties. The main conclusion from the study is that the Law of Propagation of Uncertainties can be used to estimate machining uncertainties.
Correlates and determinants of child anthropometrics in Latin America: background and overview of the symposium.

Abstract In Latin America and the Caribbean (LAC) about one in six children under 5 years of age—or about 9 million children—suffer from longer-run undernourishment reflected in stunting. This paper introduces, places in perspective and presents a common micro analytical framework for the seven papers in this symposium that investigate the household and community determinants of child malnourishment in eight countries in LAC. These papers are the outcomes of a research project supported by the Inter-American Development Bank (IDB) Research Department Latin American and Caribbean Research Network Project on “Child Health, Poverty and the Role of Social Policies” in 2003–2004.
Poisson Involutions, Spin Calogero-Moser Systems Associated with Symmetric Lie Subalgebras and the Symmetric Space Spin Ruijsenaars-Schneider Models

We develop a general scheme to construct integrable systems starting from realizations in symmetric coboundary dynamical Lie algebroids and symmetric coboundary dynamical Poisson groupoids. The method is based on the successive use of Dirac reduction and Poisson reduction. Then we show that certain spin Calogero-Moser systems associated with symmetric Lie subalgebras can be studied in this fashion. We also consider some spin-generalized Ruisjenaars-Schneider equations which correspond to the N-soliton solutions of \(A^{(1)}_n\) affine Toda field theory. In this case, we show how the equations are obtained from the Dirac reduction of some Hamiltonian system on a symmetric coboundary dynamical Poisson groupoid.
ON THE BEURLING DIMENSION OF EXPONENTIAL FRAMES

Abstract We study Fourier frames of exponentials on fractal measures associated with a class of affine iterated function systems. We prove that, under a mild technical condition, the Beurling dimension of a Fourier frame coincides with the Hausdorff dimension of the fractal.
NEW TESTS FOR DISRUPTION MECHANISMS OF STAR CLUSTERS: THE LARGE AND SMALL MAGELLANIC CLOUDS

We compare the observed bivariate distribution of masses (M) and ages (tau) of star clusters in the Large Magellanic Cloud (LMC) with the predicted distributions g(M, tau) from three idealized models for the disruption of star clusters: (1) sudden mass-dependent disruption, (2) gradual mass-dependent disruption, and (3) gradual mass-independent disruption. The model with mass-independent disruption provides a good, first-order description of these cluster populations, with g(M, tau) {proportional_to} M {sup beta}tau{sup g}amma, beta = -1.8 +- 0.2 and gamma = -0.8 +- 0.2, at least for clusters with ages tau {approx} 10{sup 3} M{sub sun} (more specifically, tau {approx}< 10{sup 7}(M/10{sup 2} M{sub sun}){sup 1.3} yr). This model predicts that the clusters should have a power-law luminosity function, dN/dL {proportional_to} L {sup -1.8}, in agreement with observations. The first two models, on the other hand, fare poorly when describing the observations, refuting previous claims that mass-dependent disruption of star clusters is observed in the LMC over the studied M-tau domain. Clusters in the SMC can be described by the same g(M, tau) distribution as for the LMC, but with smaller samples and hence larger uncertainties. The successful g(M, tau) model for clusters inmore » the Magellanic Clouds is virtually the same as the one for clusters in the merging Antennae galaxies, but extends the domain of validity to lower masses and to older ages. This indicates that the dominant disruption processes are similar in these very different galaxies over at least tau {approx}< 10{sup 8} yr and possibly tau {approx}< 10{sup 9} yr. The mass functions for young clusters in the LMC are power laws, while that for ancient globular clusters is peaked. We show that the observed shapes of these mass functions are consistent with expectations from the simple evaporation model presented by McLaughlin and Fall.« less
Mn3+ in trigonal bipyramidal coordination: a new blue chromophore.

We show that trivalent manganese, Mn3+, imparts an intense blue color to oxides when it is introduced at dilution in trigonal bipyramidal coordination. Our optical measurements and first-principles density functional theory calculations indicate that the blue color results from an intense absorption in the red/green region. This absorption is due in turn to a symmetry-allowed optical transition between the valence-band maximum, composed of Mn 3dx2−y2,xy states strongly hybridized with O 2px,y states, and the narrow Mn 3dz2-based conduction-band minimum. We begin by demonstrating and explaining the effect using a well-defined prototype system: the hexagonal YMnO3−YInO3 solid solution. We then show that the behavior is a general feature of diluted Mn3+ in this coordination environment.
Non-carbonyl-stabilized metallocarbenoids in synthesis: the development of a tandem rhodium-catalyzed bamford-stevens/thermal aliphatic claisen rearrangement sequence.

A tandem rhodium-catalyzed Bamford−Stevens/Claisen rearrangement is presented. The tandem reaction uses Eschenmoser hydrazones for the in situ generation of non-carbonyl-stabilized diazo alkanes, which are presumably intercepted by Rh(II) catalysts to induce a 1,2-hydride migration. This sequence provides high levels of stereocontrol for the generation of simple acyclic (Z)-enol ethers. These enol ethers undergo either thermal or Lewis acid accelerated Claisen rearrangements to provide products of high diastereopurity. Also presented are cascade reactions, wherein a third chemical step occurs after the initial tandem sequence (i.e., Bamford−Stevens/Claisen/ene and Bamford−Stevens/Claisen/Cope).
Incentive Effects of Inheritances and Optimal Estate Taxation

I consider optimal nonlinear taxation of income and bequests with a joy-of-giving bequest motive and explicitly characterize the optimal estate tax rate. The optimal formula trades off correction of externality from giving and discouraging effort of children due to income effect generated by bequests. The analysis shows that optimality of a positive tax on bequests rests on the strength of the effect of bequests on behavior of future generations. The analysis also suggests that inheritance, rather than estate tax, is better suited to implement the optimal policy.
Generation of (5.5.n) Tricyclic Ring Systems by Radical-Promoted Inter- and Intramolecular (3 + 2) Cycloadditions

A new method for the synthesis of [5.5.n] tricyclic ring systems via radical fragmentation and double cyclization is described. The general process (Scheme 1) involves addition of an alkylthio radical to an alkenylcyclopropane 1 to generate the cyclopropylcarbinyl radical which opens to the homoallylic radical; this radical then adds to an alkene or alkyne radical trap to give a new alkyl radical which then adds back to the thioalkyl allylic system to generate, after loss of the alkylthio radical, the bi- or tricyclic product, 2, thus making the process analogous to a [3 + 2] cycloaddition. Thus addition of the butylthio radical (generated by photolysis of dibutyl disulfide) to the bicyclo[3.1.0]hex-2-en-6-yl carboxylate 3 in the presence of an alkene or alkyneeither an acyclic radical trap, e.g., ethyl vinyl ether, isopropenyl acetate, methyl acrylate, or methyl propiolate, or a cyclic one, e.g., cyclopentenone, dihydrofuran, cyclopentenyl acetate, or cyclopenteneaffords the desired bi- or tricyclic prod...
Role of Teichoic Acid in the Binding of Staphylococcus aureus to Nasal Epithelial Cells

The role of teichoic acid in the adherence of Staphylococcus aureus to nasal epithelial cells was investigated. Epithelial cells treated with teichoic acid demonstrated decreased binding of S. aureus. A 71% reduction of adherence was noted with teichoic acid-treated epithelial cells as compared with controls (P less than 0.001). Reduction in adherence of S. aureus was also noted with lipoteichoic acid (obtained from streptococci)-treated epithelial cells. The data provide evidence that teichoic acid mediates the adherence of S. aureus to nasal mucosal cells.
Scaling beyond CMOS: Turing-Heisenberg Rapproachment

The primary objective of this study is to explore the connection of the device physics in the Boltzmann-Heisenberg limits and the parameters of the digital circuits implemented from these devices. We offer an abstraction of a Minimal Turing Machine built from the limiting devices and circuits, thus Turing-Heisenberg Rapprochement. The analysis suggests a possible limit to computational performance similar to the Carnot efficiency limit for heat engines.
CT densitometry of pulmonary nodules: a phantom study.

ABSTRACTDensity determinations by computed tomography (CT) have been used to distinguish benign from malignant pulmonary nodules. Unfortunately, clinical scanning of pulmonary nodules frequently yields artifactually low CT numbers because of partial volume artifacts from the surrounding aerated lung
Asymmetric alkylations of n-acyl dihydropyrimidinones

Abstract Enantiomerically pure dihydropyrimidin-4-one 1 has been employed as a chiral auxiliary for enantioselective alkylation reactions. Acylation of 1 , followed by enolate formation, alkylation and acyl cleavage, affords α-alkylated carboxylic acids in high chemical yield and enatiomeric purity.