cssi/SciSciGPT-SciSciNet huggingface dataset:
An Efficient Synthesis of [2.2.1] Heterobicyclic Pyroglutamates

A novel methodology for the efficient synthesis of [2.2.1] heterobicyclic pyroglutamates has been described. The key synthetic steps involve alkylation of amino acid-derived iminoesters with Baylis-Hillman bromide, RhCl3-catalyzed exocyclic olefin isomerization, diastereoselective dihydroxylation, and regioselective lactonization. All the compounds were evaluated for their cytotoxicity using multiple myeloma cancer cell lines RPMI 8226.
Interfacial Drag for Two-Phase Flow Through High Permeability Porous Beds

Pressure drop and void fraction measurements in two-phase (air-water) flow through porous beds of randomly packed spheres have been used to determine the interfacial gas-liquid drag and the gas-solid drag for the case of zero net liquid flux through the bed. The results, presented for beds of 3.18-, 6.35-, and 12.7-mm spheres, show that the interfacial gas-liquid drag term is of the same order as the gas-solid drag term when the particle size is greater than 6 mm.
Towards understanding modern web traffic

As Web sites move from relatively static displays of simple pages to rich media applications with heavy client-side interaction, the nature of the resulting Web traffic changes as well. Understanding this change is necessary in order to improve response time, evaluate caching effectiveness, and design intermediary systems, such as firewalls, security analyzers, and reporting/management systems. Unfortunately, we have little understanding of the underlying nature of today's Web traffic.In this paper, we analyze five years (2006-2010) of real Web traffic from a globally-distributed proxy system, which captures the browsing behavior of over 70,000 daily users from 187 countries. Using this data set, we examine major changes in Web traffic characteristics that occurred during this period. We also present a new Web page analysis algorithm that is better suited for modern Web page interactions by grouping requests into streams and exploiting the structure of the pages. Using this algorithm, we analyze various aspects of page-level changes, and characterize modern Web pages. Finally, we investigate the redundancy of this traffic, using both traditional object-level caching as well as content-based approaches.
Origin, microbiology, nutrition, and pharmacology of D-amino acids

Exposure of food proteins to certain processing conditions induces two major chemical changes: racemization of all L-amino acids (LAAs) to D-amino acids (DAAs) and concurrent formation of cross-linked amino acids such as lysinoalanine (LAL). The diet contains both processing-induced and naturally-formed DAA. The latter include those found in microorganisms, plants, and marine invertebrates. Racemization impairs digestibility and nutritional quality. Racemization of LAA residues to their D-isomers in food and other proteins is pH-, time-, and temperature-dependent. Although racemization rates of LAA residues in a protein vary, relative rates in different proteins are similar. The nutritional utilization of different DAAs varies widely in animals and humans. Some DAAs may exert both adverse and beneficial biological effects. Thus, although D-Phe is utilized as a nutritional source of L-Phe, high concentrations of D-Tyr in such diets inhibit the growth of mice. Both D-Ser and LAL induce histological changes in the rat kidney. The wide variation in the utilization of DAAs is illustrated by the fact that, whereas D-Meth is largely utilized as a nutritional source of the L-isomer, D-Lys is not. Similarly, although L-CysSH has a sparing effect on L-Meth when fed to mice, D-CysSH does not. Since DAAs are consumed as part of their normal diet, a need exists to develop a better understanding of their roles in foods, microbiology, nutrition, and medicine. To contribute to this effort, this overview surveys our present knowledge of the chemistry, nutrition, safety, microbiology, and pharmacology of DAAs. Also covered are the origin and distribution of DAAs in food and possible roles of DAAs in human physiology, aging, and the etiology and therapy of human diseases.
Benign convulsions with mild gastroenteritis: a report of 10 recent cases detailing clinical varieties

To better define the characteristic clinical features of benign convulsions with mild gastroenteritis, recently recognized as a new entity in Japan, we reviewed all the 10 patients we have seen from 1992 to 1994. The clinical features have been previously reported in the literature to be afebrile generalized tonic-clonic seizures occurring between the first and the fifth sick day of mild gastroenteritis. In our series, four of 10 patients had convulsions before the onset of gastroenteritis. Overall, seizures were mostly brief and often repetitive occurring in cluster (19 seizures/10 episodes). Among these, a prolonged or partial seizure was frequently observed. In six of the 10 patients, the seizure type changed during an episode: from generalized to partial seizures (n = 2), from partial to generalized seizures (n = 2), or from partial to another type of partial seizures (n = 2). None in our series experienced a recurrence episode of afebrile convulsion during follow-up. These findings suggest that benign convulsions with mild gastroenteritis exhibit some variations in their clinical manifestation.
Symmetry Reduction of Exterior Differential Systems and Bäcklund Transformations for PDE in the Plane

We approach the construction of Backlund transformations for Darboux integrable hyperbolic partial differential equations in the plane through the reduction of exterior differential systems.
The Impact of Ethical Leadership, the Internal Audit Function, and Moral Intensity on a Financial Reporting Decision

Two elements of corporate governance—the strength of ethical executive leadership and the internal audit function (IAF hereafter)—provide guidance to accounting managers making decisions involving uncertainty. We examine the joint effect of these two factors, manipulated at two levels (strong, weak), in an experiment in which accounting professionals decide whether to book a questionable journal entry (i.e., a journal entry for which a reasonable business case can be made but there is no supporting documentation). We find that ethical leadership and the IAF interact to determine the likelihood that accountants book the entry. Specifically, accountants are less likely to book a questionable journal entry when there is a weak ethical leader and a strong IAF compared to all other conditions. In addition, we find that accountants question the appropriateness and ethicalness of the request to book an undocumented journal entry more in the weak ethical leader and strong IAF condition than in the other conditions. These results suggest that the IAF has a different impact on financial reporting decisions depending on the ethicalness of executive leadership and that a strong IAF may cause accountants to question the appropriateness and ethicalness of an undocumented journal entry when combined with weak ethical leadership. We also find that the interactive effect of ethical leadership and the IAF on an accountant’s decision is fully mediated by his/her perception of the moral intensity of the issue. Thus, accountants, who perceive greater moral intensity associated with booking the entry, are less willing to do so.
Compton-thick X-ray absorption in the Seyfert galaxies Tololo 0109-383 and ESO 138-G1

We present analyses of the ASCA X-ray spectra of two Seyfert galaxies, Tololo 0109-383 and ESO 138-G1. In both cases, spectral fitting reveals two statistically acceptable continuum models: Compton reflection and partial covering. Both spectra have strong iron K-alpha lines, with equivalent widths greater than 1.5 keV. These large equivalent widths are suggestive of heavier obscuration than that directly indicated by the partial-covering models (approximately 2 x 10^23 cm^-2), with the actual column densities being `Compton-thick' (i.e. N_H > 1.5 x 10^24 cm^-2). We use the hard X-ray/[O III] flux correlation for Seyferts and data from the literature to provide additional support for this hypothesis. Since Tololo 0109-383 is known to have optical type 1 characteristics such as broad Balmer line components and Fe II emission, this result marks it as a notable object.
VORTEX INTERACTIONS IN MULTIPLE VORTEX WAKES BEHIND AIRCRAFT

A flow visualization technique has been developed that allows the nature of lift-generate d wakes behind aircraft models to be investigated. The technique is applicable to models being towed underwater in a ship model basin. Several different configurations of a 0.61-m (2-ft) span model of a Boeing 747-type transport aircraft were tested to allow observation of typical vortex interactions and merging in multiple vortex wakes. The vortices were identified by emitting tracer dyes from selected locations on the model. Their trajectories were obtained from photographs of the wake. Wingspan loading and model attitude were found to effect both vortex motions within the wake and resulting far-field wake velocity. Landing-gear deployment caused a far-field reformation of vorticity behind a model configuration which dissipated concentrated vorticity in the near-field wake. Circulation from the wing always caused a downward movement of the horizontal tail vortices, which merged with wing vortices. A modified landing configuration was developed that appeared to significantly alleviate the concentrated wake vorticity associated with the current landing configuration.
Diastereoselective zirconocene-promoted bicyclization-carbonylation of allylically methyl-substituted enynes. Synthesis of (+)-iridomyrmecin

Abstract Allylically methyl-substituted 1,6-heptenynes, such as 3-methyl-1,6-octenyne, can be diastereoselectivity converted to the corresponding bicyclic ketones, such as (5R, 6S)-2,6-dimethylbicyclo[3.3.0]oct-1-en-3-one readily convertible to (+)-iridomyrmecin, the observed diastereomeric excesses of the bicyclization reaction being >90%.
Current status of cord blood banking and transplantation in the United States and Europe

Abstract Cord blood (CB) transplantation has expanded the ability of the transplantation community to meet the growing needs of their patients. Clinical data over the last decade show promising results in CB transplantation using blood from related as well as unrelated donors. Basic science continues to look for ways to expand the quality and quantity of CB. CB banks are now established around the world, with major efforts to standardize banking to facilitate regulation, collection, processing, and distribution as a way of providing the highest-quality CB for patient use. This review article discusses the current status of CB transplantation and banking in the United States and Europe. Biol Blood Marrow Transplant 2001;7(12):635-45.
The HP AutoRAID hierarchical storage system

Configuring redundant disk arrays is a black art. To configure an array properly, a system administrator must understand the details of both the array and the workload it will support. Incorrect understanding of either, or changes in the workload over time, can lead to poor performance. We present a solution to this problem: a two-level storage hierarchy implemented inside a single disk-array controller. In the upper level of this hierarchy, two copies of active data are stored to provide full redundancy and excellent performance. In the lower level, RAID 5 parity protection is used to provide excellent storage cost for inactive data, at somewhat lower performance. The technology we describe in this article, know as HP AutoRAID, automatically and transparently manages migration of data blocks between these two levels as access patterns change. The result is a fully redundant storage system that is extremely easy to use, is suitable for a wide variety of workloads, is largely insensitive to dynamic workload changes, and performs much better than disk arrays with comparable numbers of spindles and much larger amounts of front-end RAM cache. Because the implementation of the HP AutoRAID technology is almost entirely in software, the additional hardware cost for these benefits is very small. We describe the HP AutoRAID technology in detail, provide performance data for an embodiment of it in a storage array, and summarize the results of simulation studies used to choose algorithms implemented in the array.
ACID-MEDIATED, CHROMIUM-CATALYZED ALLYLATION OF ALDEHYDES

Allyl bromides are efficiently coupled with aryl and aliphatic aldehydes in the presence of manganese metal, collidine hydrochloride, bis(diisopropylphosphino)ethane and chromium dichloride. Homoallylic alcohols are isolated in good to excellent yields directly from the reaction mixture.
Oncologic outcomes and prognostic impact of urothelial recurrences in patients undergoing segmental and total ureterectomy for upper tract urothelial carcinoma.

Introduction: We evaluated the impact of urothelial recurrences in a cohort of patients undergoing segmental (SU) and total ureterectomy (TU) as an alternative to nephroureterectomy (NU) for upper tract urothelial carcinoma. Methods: Between 1999 and 2012, patients who underwent SU, TU and NU for treatment of upper tract urothelial carcinoma were evaluated. Demographic, surgical, pathologic and oncologic data were collected. Recurrence-free (RFS) and disease-specific survival (DSS) were analyzed using Kaplan-Meier and multivariable Cox methods. Results: A total 141 patients were evaluated, 35 underwent SU, 10 TU and 96 NU. Patients who underwent TU were more likely to have bilateral disease (p < 0.01), solitary kidney (p < 0.01), and multifocal disease (p = 0.01). Organ-confined (p < 0.01) and lowgrade disease (p < 0.01) were more common in the TU and SU groups compared with NU. At a median follow-up of 56.9 months (range: 0.2–181.1) disease relapse occurred in 88 (55.3%) patients. Localized recurrence occurred in 31.1% of SU/TU group compared to 27.1% (p = 0.62) of the NU group. Neither total nor segmental ureterectomy demonstrated significantly worse RFS (p = 0.26 and p = 0.81), CSS (p = 0.96 and p = 0.52) or overall survival (p = 0.59 and p = 0.55) compared with complete NU. Localized urothelial recurrence did not confer increased risk of cancer-specific (p = 0.73) or overall mortality (p = 0.39). The paper’s most important limitations include its retrospective nature and its relatively small number of patients. Conclusion: No significant survival differences were demonstrated between surgical approaches for upper tract urothelial cancer. Localized urothelial recurrence after surgical treatment for upper tract urothelial cancer does not affect mortality in this population. TU with ileal-substitution may provide an alternative option for patients with extensive ureteral disease and poor renal function.
Profile Shapes for Optically Thick X-ray Emission Lines from Stellar Winds.

We consider the consequences of appreciable line optical depth for the profile shape of X-ray emission lines formed in stellar winds. The hot gas is thought to arise in distributed wind shocks, and the line formation is predominantly via collisional excitation followed by radiative decay. Such lines are often modeled as optically thin, but the theory has difficulty matching resolved X-ray line profiles. We suggest that for strong lines of abundant metals, newly created photons may undergo resonance scattering, modifying the emergent profile. Using Sobolev theory in a spherically symmetric wind, we show that thick-line resonance scattering leads to emission profiles that still have blueshifted centroids, like the thin lines, but are considerably less asymmetric in appearance. We focus on winds in the constant-expansion domain and derive an analytic form for the profile shape in the limit of large line and photoabsorptive optical depths. In this limit the emission profile reduces to a universal shape and has a centroid shift of -0.24v∞, with a half-width at half-maximum (HWHM) of 0.63v∞. Using published data for Chandra observations of five emission lines from the O star ζ Pup, we find that the observed HWHMs are somewhat smaller than predicted by our theory; however, the centroid shifts of all five lines are consistent with our theoretical result. These optical depth effects can potentially explain the more nearly symmetric emission lines observed in ζ Ori, θ1 Ori C, and δ Ori by Chandra, although an alternative explanation is required to account for the unshifted peak line emission. We also consider enhanced reabsorption by continuous opacity as line photons multiply scatter within an optically thick line, and find, for lines with optical depths of a few, that such reabsorption can further reduce the line asymmetry. It also reduces the line equivalent width, but probably not enough to alleviate the problem of subsolar metallicities inferred from O star X-ray spectra by ASCA, unless the width of the resonance regions are superthermally enhanced.
Mitochondrial and nuclear genomic responses to loss of LRPPRC expression

Rapid advances in genotyping and sequencing technology have dramatically accelerated the discovery of genes underlying human disease. Elucidating the function of such genes and understanding their role in pathogenesis, however, remain challenging. Here, we introduce a genomic strategy to characterize such genes functionally, and we apply it to LRPPRC, a poorly studied gene that is mutated in Leigh syndrome, French-Canadian type (LSFC). We utilize RNA interference to engineer an allelic series of cellular models in which LRPPRC has been stably silenced to different levels of knockdown efficiency. We then combine genome-wide expression profiling with gene set enrichment analysis to identify cellular responses that correlate with the loss of LRPPRC. Using this strategy, we discovered a specific role for LRPPRC in the expression of all mitochondrial DNA-encoded mRNAs, but not the rRNAs, providing mechanistic insights into the enzymatic defects observed in the disease. Our analysis shows that nuclear genes encoding mitochondrial proteins are not collectively affected by the loss of LRPPRC. We do observe altered expression of genes related to hexose metabolism, prostaglandin synthesis, and glycosphingolipid biology that may either play an adaptive role in cell survival or contribute to pathogenesis. The combination of genetic perturbation, genomic profiling, and pathway analysis represents a generic strategy for understanding disease pathogenesis.
Regime switching and wages in major league baseball under the reserve clause

Over the course of the twentieth century, American wages increased by a factor of about 100, while the wages of professional baseball players increased by a factor of 450, but that increase was neither smooth nor consistent. We use a unique and expansive dataset of salaries and performance variables of Major League Baseball pitchers that spans over 400 players and 60 years during the reserve clause era to identify factors that determine salaries and examine how the importance of various factors have changed over time. We employ a Markov regime-switching regression model borrowed from the macroeconomics literature, which allows regression coefficients to switch exogenously between two or more values as time progresses. This method lets us identify changes in wage determination that may have occurred because of a change in the league’s competitiveness, a change in the relative bargaining power between players and teams, or other factors that may be unknown or unobservable. We find that even though Major League Baseball was a tightly controlled monopsony with the reserve clause, there was a significant shift in salary determination that lasted from the Great Depression until after World War II where players’ salaries were more highly linked to their recent performance.
Fermi surface evolution in underdoped cuprates

Abstract We consider a two-dimensional Fermi liquid coupled to low-energy commensurate spin fluctuations. At small couplings, the hole Fermi surface is large and centred around (π, π). We show that, as the coupling increases, the shape of the Fermi surface undergoes a substantial evolution and, at strong couplings, the hole Fermi surface consists of small pockets centred at (±π/2, ±π/2). At intermediate couplings, there exist both a large hole Fermi surface centred at (π, π) and four hole pockets, but the quasiparticle residue is small everywhere except for the pieces of the pockets which face the Γ point. The relevance of these results to recent photoemission experiments on YBa2Cu3O7 and Bu2CaCu2O8+x systems, and their relation to the Luttinger theorem are discussed.
CYCLIC OLIGOLIDES VIA ACYLKETENE MEDIATED LACTONIZATION : SYNTHESIS AND CHARACTERIZATION

An acylketene mediated cyclization protocol delivers a series of cyclic oligolides, the largest characterized cyclic oligolide having a 77-membered ring. 6-(ω-Hydroxyalkyl)dioxinone analogs were prepared and cyclizations were conducted under a variety of conditions in refluxing toluene. 1H-NMR, 13C-NMR, and several different mass spectrometric techniques were employed to verify the cyclic nature of these oligolides.
Library-friendly synthesis of fluorinated ketones through functionalized hydration of alkynes and investigation of the reaction mechanism

Abstract A library-friendly synthesis of α-substituted-α-fluoroketones through functionalized hydration of alkynes in one pot under mild conditions is reported. The ready availability of alkynes and organoboronic acids makes this reaction quite attractive. We also studied the key intermediate—a fluorinated cationic gold species—using in situ NMR spectroscopy and ESI-high resolution mass spectrometry.
Modeling aspect mechanisms: a top-down approach

A plethora of aspect mechanisms exist today. All of these diverse mechanisms integrate concerns into artifacts that exhibit crosscutting structure. What we lack and need is a characterization of the design space that these aspect mechanisms inhabit and a model description of their weaving processes. A good design space representation provides a common framework for understanding and evaluating existing mechanisms. A well-understood model of the weaving process can guide the implementor of new aspect mechanisms. It can guide the designer when mechanisms implementing new kinds of weaving are needed. It can also help teach aspect-oriented programming (AOP). In this paper we present and evaluate such a model of the design space for aspect mechanisms and their weaving processes. We model weaving, at an abstract level, as a concern integration process. We derive a weaving process model (WPM) top-down, differentiating a reactive from a nonreactive process. The model provides an in-depth explanation of the key subprocesses used by existing aspect mechanisms.
Statistical method of noise estimation in a synchronous system

This paper describes a process developed by IBM engineers and programmers to analyze coupled noise within a synchronous digital machine. Former methods simply summed noise components or used root mean square techniques to estimate the total cross-talk on a quiet line. A method that considers the spatial relationship of the noise generating components as well as the timing of the incident pulses is discussed. Consideration is given to factors such as path delay, reflected noise, driver slew rate, noise pulse width, termination, net topology, noise from other sources and the probabilistic nature of the time when a signal is launched as well as other parameters. The result is a probability of achieving a noise level on the circuit and a noise versus time envelope. The method is more accurate than previous techniques due to timing and statistical considerations. Treatment of the resultant output is discussed and compared to simpler deterministic methods. Failure criterion, critical time periods and some sources of errors are also considered. >
Porphyrins and metalloporphyrins: versatile circular dichroic reporter groups for structural studies.

During the last few years, porphyrins and metalloporphyrins have at- tracted widespread attention as chromophores for studies in circular dichroism (CD), an indispensable chiroptical tool for monitoring chiral interactions. This review summarizes the multifaceted properties of porphyrins and metalloporphyrins, powerful CD chromo- phores that are characterized by their intense and red-shifted Soret band, propensity to undergo p-p stacking, facile incorporation of metals, and ease in varying solubility. Such attributes make porphyrins one of the most attractive and sensitive chromophores used in CD studies. They offer possibilities for studying the stereochemistry of chiral por- phyrin assemblies, large organic molecules, biopolymers, and compounds available in miniscule quantities. The tendency of porphyrins to undergo p-p stacking and zinc porphyrins to coordinate with amines enable the CD exciton chirality method to be extended to configurational assignments of flexible compounds containing only one stereogenic center. Various artificial porphyrin receptors have been synthesized for the recognition of biologically important chiral guests such as carbohydrates, amino acids, and their derivatives. The induced CD of the host porphyrin Soret band reflects the identity of guests and binding modes of host/guest complexation with high sensitivity. Chirality 12:237-255, 2000. © 2000 Wiley-Liss, Inc.
Rhodium-catalyzed synthesis of cyclohexenones via a novel [4 + 2] annulation.

In the presence of a rhodium catalyst, 4-alkynals react with alkynes to furnish cyclohexenones, presumably via metalacycle 1; as far as we are aware, this is the first example of the generation of this class of compounds through such a transformation. In view of the easy accessibility of 4-alkynals (alkynylmetal + α,β-unsaturated aldehyde) and alkynes, this [4 + 2] cyclization constitutes an interesting new approach to functionalized cyclohexenones.
Scaling of impact-loaded carbon-fiber composites

The application of scaling laws to fiber composite laminates is discussed. Particular emphasis is placed on the case of impact loading. Scaling difficulties and conflicts are identified and illustrated in an experimental program based on impacted carbon-fiber composite beams. It is shown that the lay-up of laminates is important in assessing the likely validity of scale-model tests for such composites. It is also observed that significant size effects may dominate strength modeling.
Use of Echocardiography in Patients with Prolapsed Mitral Valve

The echocardiographic findings are described for five patients who had the prolapsed mitral valve syndrome, proven by cardiac catheterization and angiocardiography. In all five patients, the echocardiograms demonstrated posterior displacement of the posterior mitral leaflet during systole. In four of the patients there was also posterior displacement of the anterior leaflet. Four of the five patients had mitral insufficiency, demonstrated by cineangiography. These four patients demonstrated echocardiographic separation of the anterior and posterior leaflets of the mitral valve in late systole. The fifth patient did not show this separation, and she had no mitral insufficiency by selective cineangiography. Two patients were given amyl nitrite during the echocardiographic examination, and the echogram showed earlier separation of the anterior and posterior leaflets as well as lengthening of the murmur. Echocardiography should be a very useful noninvasive, yet direct, method for diagnosing, studying, and following patients with prolapse of the mitral valve.
Some cases of the Eisenbud-Green-Harris conjecture

The Eisenbud-Green-Harris conjecture states that a homogeneous ideal in $\K[x_1,\dots,x_n]$ containing a homogeneous regular sequence $f_1,\dots,f_n$ with $\deg(f_i)=a_i$ has the same Hilbert function as an ideal containing $x_i^{a_i}$ for $1 \leq i \leq n$. In this paper we prove the Eisenbud-Green-Harris conjecture when $a_j > \sum_{i=1}^{j-1} (a_i-1)$ for all $j>1$. This result was independently obtained by the two authors.
On the notion of relative property (T) for inclusions of von Neumann algebras

Abstract We prove that the notion of rigidity (or relative property (T)) for inclusions of finite von Neumann algebras recently defined by the second author is equivalent to a weaker property, in which no “continuity constants” are required. The proof is by contradiction and uses infinite products of completely positive maps, regarded as correspondences.
Oil Prices and Real Exchange Rates in Oil-Exporting Countries: A Bounds Testing Approach

We test the validity of the Dutch disease hypothesis by examining the relationship between real oil prices and real exchange rates in a sample of fourteen oil exporting countries. Autoregressive distributed lag (ARDL) bounds tests of cointegration support the existence of a stable relationship between real exchange rates and real oil prices in all countries, suggesting a strong support for the Dutch disease hypothesis.
Aggregate price effects of institutional trading: a study of mutual fund flow and market returns

Abstract We study the relation between market returns and aggregate flow into U.S. equity funds, using daily flow data. The concurrent daily relation is positive. Our tests show that this concurrent relation reflects flow and institutional trading affecting returns. This daily relation is similar in magnitude to the price impact reported for an individual institution's trades in a stock. Aggregate flow also follows market returns with a one-day lag. The lagged response of flow suggests either a common response of both returns and flow to new information, or positive feedback trading.
An efficient incremental architecture for robust interpretation

In this paper we describe ROSENHEIM, the RObust SENtence level arcHitecture for Efficient Incremental Multi-sentence interpretation. Its efficiency is the result of its novel layered scheduling algorithm. This scheduling algorithm makes it possible to ensure that when edits are made to already processed portions of text, only the minimum changes are made to the chart. Thus, it allows the parser to take advantage of the user's typing or speaking time so that it can complete the majority of the work of parsing an input text before the user enters the last word. Our evaluation demonstrates that this layered architecture makes the parser's response time almost imperceptible. We also show that our incremental parser performs more efficiently than other well known incremental parsers [34] [20]. An implementation of the ROSENHEIM architecture is currently part of the WHY Conceptual Physics Tutoring System [28], one of several recent dialogue based tutoring Systems [23] [1] [7] [11].
Open/closed string duality for topological gravity with matter

The exact FZZT brane partition function for topological gravity with matter is computed using the dual two-matrix model. We show how the effective theory of open strings on a stack of FZZT branes is described by the generalized Kontsevich matrix integral, extending the earlier result for pure topological gravity. Using the well-known relation between the Kontsevich integral and a certain shift in the closed-string background, we conclude that these models exhibit open/closed string duality explicitly. Just as in pure topological gravity, the unphysical sheets of the classical FZZT moduli space are eliminated in the exact answer. Instead, they contribute small, nonperturbative corrections to the exact answer through Stokes' phenomenon.
Development of secondary standards for 223Ra.

Abstract Ra-223 is a bone-seeking alpha emitter currently being evaluated as a radiopharmaceutical. Concurrent with the primary standardization, NIST established that calibration factors currently used for radionuclide calibrators in the clinical setting give readings 5.7–8.7% higher than the NIST calibrated activity. This work describes the determination of calibration factors specific to dose vials and syringes. Using the calibration factors derived with standard ampoules to measure syringe activities can give readings up to 3.6% too high.
Comments on “Lattice formulation of the standard model” by Creutz et al.

Abstract The main construction of the paper in the title [Phys. Lett. B 402 (1997) 341] is summarized using more standard particle physics language. Also, a minor flaw is pointed out. A somewhat different perspective on the status of several proposals in lattice chiral gauge theory is presented.
ENERGY DENSITY AND PRESSURE IN POWER-WALL MODELS

A finite ultraviolet cutoff near a reflecting boundary yields a stress tensor that violates the basic energy-pressure relation. Therefore, a "soft" wall described by a power-law potential, which needs no ad hoc cutoff, is being investigated by the collaboration centered at Texas A&M University and the University of Oklahoma. Progress is reported here.
The locality-aware adaptive cache coherence protocol

Next generation multicore applications will process massive amounts of data with significant sharing. Data movement and management impacts memory access latency and consumes power. Therefore, harnessing data locality is of fundamental importance in future processors. We propose a scalable, efficient shared memory cache coherence protocol that enables seamless adaptation between private and logically shared caching of on-chip data at the fine granularity of cache lines. Our data-centric approach relies on in-hardware yet low-overhead runtime profiling of the locality of each cache line and only allows private caching for data blocks with high spatio-temporal locality. This allows us to better exploit the private caches and enable low-latency, low-energy memory access, while retaining the convenience of shared memory. On a set of parallel benchmarks, our low-overhead locality-aware mechanisms reduce the overall energy by 25% and completion time by 15% in an NoC-based multicore with the Reactive-NUCA on-chip cache organization and the ACKwise limited directory-based coherence protocol.
Twisted Modules over Vertex Algebras on Algebraic Curves

Abstract We extend the geometric approach to vertex algebras developed by the first author to twisted modules, allowing us to treat orbifold models in conformal field theory. Let V be a vertex algebra, H a finite group of automorphisms of V, and C an algebraic curve such that H⊂Aut(C). We show that a suitable collection of twisted V-modules gives rise to a section of a certain sheaf on the quotient X=C/H. We introduce the notion of conformal blocks for twisted modules, and analyze them in the case of the Heisenberg and affine Kac–Moody vertex algebras. We also give a chiral algebra interpretation of twisted modules.
Adaptive mutation in Escherichia coli.

In 1988 John Cairns, Julie Overbaugh, and Stephan Miller published a paper entitled “The origin of mutants,” in which they suggested that bacteria could choose which mutations to make (11). Shortly thereafter, Cairns and I began collaborating on a National Science Foundation-funded project to investigate the genetic basis of what was popularly called “directed mutation” (although at the time we were calling it “selection-dependent mutation,” which now seems as good a name as any). Our plan was to mutagenize an appropriate strain of Escherichia coli and identify and characterize variants defective in selection-dependent mutation. Cairns and coworkers had been investigating a strain called SM195, described in their original paper (11). However, the mechanisms of mutation in this strain had proved to be complicated, and we wanted a new experimental subject. We were setting up to investigate selection-induced activation of the cryptic bgl operon (36), when Jeffrey Miller gave us a Lac− strain, called α45, that he said had a high rate of reversion to Lac+ after plating on minimum lactose medium. The lac allele in this strain is a fusion of lacI to lacZ that eliminates the lac regulatory region as well as several residues of lacI and lacZ; transcription of the fusion is constitutive, initiating at the lacI promoter (7). α45 has a +1 frameshift mutation, lacI33, in the lacI coding region (12). Miller and coworkers have used several similar strains to study various mutational mechanisms (52, 67). As in many of the strains that originated with Jacob and Monod, proAB and lac are deleted from the chromosome and carried on an episome, F′128. This arrangement greatly facilitates genetic manipulations and turned out to be important to adaptive mutation. We mated the episome from α45 into a Δ(lac-pro) recipient that we had made rifampin resistant and named the new strain FC40 (Foster and Cairns #40).
Uncertainty and entry deterrence

We study a model where capacity installation by an incumbent firm serves to deter others from entering the industry. We argue that uncertainty about demand or costs forces the incumbent to choose a higher capacity level than it would under certainty. This higher level diminishes the attractiveness of deterrence (Proposition 1) and, therefore, the range of parameter values for which deterrence occurs (Proposition 2).
The Effect of Large-scale Magnetic Turbulence on the Acceleration of Electrons by Perpendicular Collisionless Shocks

We study the physics of electron acceleration at collisionless shocks that move through a plasma containing large-scale magnetic fluctuations. We numerically integrate the trajectories of a large number of electrons, which are treated as test particles moving in the time-dependent electric and magnetic fields determined from two-dimensional hybrid simulations (kinetic ions and fluid electron). The large-scale magnetic fluctuations effect the electrons in a number of ways and lead to efficient and rapid energization at the shock front. Since the electrons mainly follow along magnetic lines of force, the large-scale braiding of field lines in space allows the fast-moving electrons to cross the shock front several times, leading to efficient acceleration. Ripples in the shock front occurring at various scales will also contribute to the acceleration by mirroring the electrons. Our calculation shows that this process favors electron acceleration at perpendicular shocks. The current study is also helpful in understanding the injection problem for electron acceleration by collisionless shocks. It is also shown that the spatial distribution of energetic electrons is similar to in situ observations. The process may be important to our understanding of energetic electrons in planetary bow shocks and interplanetary shocks, and explaining herringbone structures seen in some type II solar radio bursts.
Control loop design for two-stage DC-DC converters with low voltage/high current output

This work presents a general analysis framework for control loop design of two-stage converters. The results yield a thorough explanation of various loop design approaches. A three-loop method to extend the system bandwidth is proposed. The new control design algorithm is applied to a 48 V/3.3 V two-stage converter. Experiments verify the effectiveness of the control loop design approach.
Disk-accreting magnetic neutron stars as high-energy particle accelerators

Interaction of an accretion disk with the magnetic field of a neutron star produces large electromotive forces, which drive large conduction currents in the disk-magnetosphere-star circuit. Here we argue that such large conduction currents will cause microscopic and macroscopic instabilities in the magnetosphere. If the minimum plasma density in the magnetosphere is relatively low is less than or aproximately 10(exp 9)/cu cm, current-driven micro-instabilities may cause relativistic double layers to form, producing voltage differences in excess of 10(exp 12) V and accelerating charged particles to very high energies. If instead the plasma density is higher (is greater than or approximately = 10(exp 9)/cu cm, twisting of the stellar magnetic field is likely to cause magnetic field reconnection. This reconnection will be relativistic, accelerating plasma in the magnetosphere to relativistic speeds and a small fraction of particles to very high energies. Interaction of these high-energy particles with X-rays, gamma-rays, and accreting plasma may produce detectable high-energy radiation.
Prediction of Turbulent Jet Mixing Noise Reduction by Water Injection

A one-dimensional control volume formulation is developed for the determination of jet mixing noise reduction due to water injection. The analysis starts from the conservation of mass, momentum and energy for the confrol volume, and introduces the concept of effective jet parameters (jet temperature, jet velocity and jet Mach number). It is shown that the water to jet mass flow rate ratio is an important parameter characterizing the jet noise reduction on account of gas-to-droplet momentum and heat transfer. Two independent dimensionless invariant groups are postulated, and provide the necessary relations for the droplet size and droplet Reynolds number. Results are presented illustrating the effect of mass flow rate ratio on the jet mixing noise reduction for a range of jet Mach number and jet Reynolds number. Predictions from the model show satisfactory comparison with available test data on perfectly expanded hot supersonic jets. The results suggest that significant noise reductions can be achieved at increased flow rate ratios.
Partially monotone tensor spline estimation of the joint distribution function with bivariate current status data

The analysis of the joint cumulative distribution function (CDF) with bivariate event time data is a challenging problem both theoretically and numerically. This paper develops a tensor spline-based sieve maximum likelihood estimation method to estimate the joint CDF with bivariate current status data. The $I$-splines are used to approximate the joint CDF in order to simplify the numerical computation of a constrained maximum likelihood estimation problem. The generalized gradient projection algorithm is used to compute the constrained optimization problem. Based on the properties of $B$-spline basis functions it is shown that the proposed tensor spline-based nonparametric sieve maximum likelihood estimator is consistent with a rate of convergence potentially better than $n^{1/3}$ under some mild regularity conditions. The simulation studies with moderate sample sizes are carried out to demonstrate that the finite sample performance of the proposed estimator is generally satisfactory.
A General-Equilibrium Analysis of Public Policy for Pharmaceutical Prices

Retail sales of prescription drugs totaled $154.5 billion in 2001 and will likely exceed $400 billion by 2010. This paper contrasts the welfare and distributional effects of the current patented-monopoly system with those of (1) a price ceiling on pharmaceutical products and (2) a universal insurance program covering pharmaceutical purchases. We use a version of the Kelton and Wallace (1995) two-good, general-equilibrium monopoly model in which a license is required to produce one good. Individuals have heterogeneous preferences, but are otherwise identical. Results indicate potential welfare gains for both the price-ceiling and universal-insurance policies, with very distinct distributional effects.
A directional microphone array for acoustic studies of wind tunnel models

An end-fire microphone array that utilizes a digital time delay system has been designed and evaluated for measuring noise in wind tunnels. The directional response of both a four- and eight-element linear array of microphones has enabled substantial rejection of background noise and reverberations in the NASA Ames 40- by 80-foot wind tunnel. In addition, it is estimated that four- and eight-element arrays reject 6 and 9 dB, respectively, of microphone wind noise, as compared with a conventional omnidirectional microphone with nose cone. Array response to two types of jet engine models in the wind tunnel is presented. Comparisons of array response to loudspeakers in the wind tunnel and in free field are made.
Contrasting Classical and Quantum Vacuum States in Non-Inertial Frames

Classical electron theory with classical electromagnetic zero-point radiation (stochastic electrodynamics) is the classical theory which most closely approximates quantum electrodynamics. Indeed, in inertial frames, there is a general connection between classical field theories with classical zero-point radiation and quantum field theories. However, this connection does not extend to noninertial frames where the time parameter is not a geodesic coordinate. Quantum field theory applies the canonical quantization procedure (depending on the local time coordinate) to a mirror-walled box, and, in general, each non-inertial coordinate frame has its own vacuum state. In particular, there is a distinction between the “Minkowski vacuum” for a box at rest in an inertial frame and a “Rindler vacuum” for an accelerating box which has fixed spatial coordinates in an (accelerating) Rindler frame. In complete contrast, the spectrum of random classical zero-point radiation is based upon symmetry principles of relativistic spacetime; in empty space, the correlation functions depend upon only the geodesic separations (and their coordinate derivatives) between the spacetime points. The behavior of classical zero-point radiation in a noninertial frame is found by tensor transformations and still depends only upon the geodesic separations, now expressed in the non-inertial coordinates. It makes no difference whether a box of classical zero-point radiation is gradually or suddenly set into uniform acceleration; the radiation in the interior retains the same correlation function except for small end-point (Casimir) corrections. Thus in classical theory where zero-point radiation is defined in terms of geodesic separations, there is nothing physically comparable to the quantum distinction between the Minkowski and Rindler vacuum states. It is also noted that relativistic classical systems with internal potential energy must be spatially extended and can not be point systems. The classical analysis gives no grounds for the “heating effects of acceleration through the vacuum” which appear in the literature of quantum field theory. Thus this distinction provides (in principle) an experimental test to distinguish the two theories.
Synthesis of 2-Substituted 7-Hydroxybenzofuran-4-carboxylates via Addition of Silyl Enol Ethers to o-Benzoquinone Esters

Mukaiyama Michael addition of silyl enol ethers 13 to the 1,2-quinone-4-carboxylate 6 (formed in situ by oxidation of the catechol ester 8) afforded the 2-subsituted 7-hydroxybenzofuran-4-carboxylates 14 in fair to good yields. Alkyl and aryl systems work well, but highly electron-rich silyl enol ethers could not be used because of competing oxidation.
Quantum time-space tradeoffs for sorting

We investigate the complexity of sorting in the model of sequential quantum circuits. While it is known that in general a quantum algorithm based on comparisons alone cannot outperform classical sorting algorithms by more than a constant factor in time complexity, this is wrong in a space bounded setting. We observe that for all storage bounds n/log ≥ S ≥ log3n, one can devise a quantum algorithm that sorts n numbers (using comparisons only) in time T=O(n3/2 log3/2n/√S). We then show the following lower bound on the time-space tradeoff for sorting n numbers from a polynomial size range in a general sorting algorithm (not necessarily based on comparisons): TS=Ω(n3/2). Hence for small values of S the upper bound is almost tight. Classically the time-space tradeoff for sorting is TS=Θ(n2).