cssi/SciSciGPT-SciSciNet huggingface dataset:
Spinal cord ischemia may be reduced via a novel technique of intercostal artery revascularization during open thoracoabdominal aneurysm repair

Objective To describe a novel technique for maximal reimplantation of intercostal arteries during thoracoabdominal aortic aneurysm repair. Methods Eight patients underwent thoracoabdominal aortic aneurysm (TAAA) repair with this new technique from 2005 to 2006. Follow-up ranged from 6 to 14 months. All patients had a previous type B dissection with subsequent aneurysmal degeneration into an extent I TAAA. Aneurysm repair was performed through a thoracoabdominal incision and circulatory arrest in seven and left atrial-left femoral (LA-FA) bypass in one. The grafts extended from the distal arch at the subclavian artery to the visceral and renal arteries. An 8 mm graft was then extended from the proximal to the distal graft with a spatulation of the graft allowing a side-to-side anastomosis of the graft to the posterior aortic wall incorporating multiple pairs of intercostal arteries. Intraoperative electroencephalogram (EEG) and somatosensory evoked potentials (SSEP) were monitored during each operation. Results All patients were ambulatory at the time of admission. One patient had suffered a previous spinal cord infarction from the original dissection and had residual unilateral leg weakness prior to the TAAA repair. There was an average of seven pairs of patent intercostal arteries upon opening the aorta. We reimplanted an average of five pairs of vessels. There were no perioperative complications. No patients sustained transient or permanent paraplegia in the postoperative or follow-up period. The one patient with preoperative leg weakness had reported subjective increased strength in the affected leg after the operation. In four cases, normalization of SSEP waveforms did not occur until after reimplantation of the intercostal arteries despite full return of EEG waveforms, restoration of lower extremity perfusion, and rewarming of the patient. Follow-up CT scan angiogram demonstrated that all reconstructions were patent through the follow-up period. Conclusions Paraplegia is an extremely morbid complication associated with TAAA repair. We describe a technique that allows reimplantation of almost all intercostal arteries as one patch circumventing the need for selective reimplantation. Furthermore, our technique ensures continued patency of this patch graft as the outflow resistance is decreased by creating a continuous flow loop. Although this is a small case series, we had no incidence of acute or delayed paraplegia in this high risk group. Our technique of intercostal reimplantation is applicable to all open TAAA repair at high-risk for paraplegia and may be an important adjunct in preventing spinal cord ischemia.
Propulsive Aerodynamics of an Advanced Nozzle/Forward Swept Wing Aircraft Configuration

Nonaxisymmetric exhaust nozzles can offer advanced aircraft configurations improved performance through the propulsive-aerodynamic interaction of the jet exhaust and the wing flowfield. An experimental investigation of this interaction was conducted at Mach numbers from 0.3 to 0.9 on a half-span wing-body configuration with vectoring (0, 15, 30 deg) nonaxisymmetric exhaust nozzles incorporated into the trailing edge of a forward swept wing. Results indicate that at all Mach numbers, the aerodynamic lift and drag coefficients increase while the pitching moment coefficient becomes more negative with increasing nozzle vectoring and nozzle flow. Thrust vectoring improves the aircraft drag polar especially at higher angles of attack.
Contemporary Women's Perceptions of Childbirth Education.

The purpose of this grounded theory study was to describe and understand contemporary childbearing women's perceptions of the role of childbirth education in preparing for birth. Participants were interviewed three times: prior to beginning classes, at the end of classes, and within 2 weeks after giving birth. Constant comparative analysis of the data was concurrent with data collection. The core process that emerged was “Negotiating the Journey,” with supporting categories of “Exploring the Unknown,” “Making It Real,” and “Sensing the Readiness.” The findings indicated that, for contemporary women, the value of childbirth education may not be in affecting physiological birth outcomes but rather in helping them to be ready for childbirth and, thereby, completing an important developmental milestone.
Hypermoduli Stabilization, Flux Attractors, and Generating Functions

We study stabilization of hypermoduli with emphasis on the effects of generalized fluxes. We find a class of no-scale vacua described by ISD conditions even in the presence of geometric flux. The associated flux attractor equations can be integrated by a generating function with the property that the hypermoduli are determined by a simple extremization principle. We work out several orbifold examples where all vector moduli and many hypermoduli are stabilized, with VEVs given explicitly in terms of fluxes.
An Improvement to Zaremba’s Conjecture

We prove there exists a density one subset \({\mathfrak{D} \subset \mathbb{N}}\) such that each \({n {\in} {\mathfrak{D}}}\) is the denominator of a finite continued fraction with partial quotients bounded by 5.
Extremum problems for eigenvalues of discrete Laplace operators

The P1 discretization of the Laplace operator on a triangulated polyhedral surface is related to geometric properties of the surface. This paper studies extremum problems for eigenvalues of the P1 discretization of the Laplace operator. Among all triangles, an equilateral triangle has the maximal first positive eigenvalue. Among all cyclic quadrilaterals, a square has the maximal first positive eigenvalue. Among all cyclic n-gons, a regular one has the minimal value of the sum of all positive eigenvalues and the minimal value of the product of all positive eigenvalues. Highlights? This paper studies extremum problems for eigenvalues of the discrete Laplace operators. ? Among all triangles, an equilateral triangle has the maximal first positive eigenvalue. ? Among all cyclic quadrilaterals, a square has the maximal first positive eigenvalue. ? Among all cyclic n-gons, a regular one has the minimum of the sum and the product of nontrivial eigenvalues.
Excluded-volume effects of molecular vibrations in a one-dimensional gas

Some thermodynamic properties are found for a system composed of N rod-like molecules in one-dimension (1D), where a molecule’s length oscillates with an amplitude determined by its (quantized) vibrational energy. Evaluation of the partition function requires integrations over the internal phases describing the oscillations, as well as the molecular positions and momenta. For N>1 and large system length L, the average energy of the system is increased—compared to that for a system of rigid rods—as are the entropy and compressibility; the pressure, however, is decreased, and there is a variable eect on the heat capacity. These changes can be traced to an eective increase in the 1D volume available to the molecules, the increase being larger for higher energy states. This behaviour is collective: a system composed of a single oscillating molecule mixed with fixed-length rods shows similar alterations in its properties, whereas a single oscillating molecule alone does not (as long as L is greater than the molecule’s maximum length). For small N, the oscillations have minimal influence when L is large compared to the combined length of all molecules, but dominate when the two become comparable.
Time-resolved fluorescence in semiconducting single-wall carbon nanotubes

Time-resolved fluorescence in single-wall carbon nanotubes (SWNTs) has been investigated by optical Kerr gating. A fast non-radiative relaxation process on 10 ps time scale was measured and a radiative lifetime of 110 ns was deduced
Reconstructing a three-dimensional model with arbitrary errors

A number of current technologies allow for the determination of interatomic distance information in structures such as proteins and RNA. Thus, the reconstruction of a three-dimensional set of points using information about its interpoint distances has become a task of basic importance in determining molecular structure. The distance measurements one obtains from techniques such as NMR are typically sparse and error-prone, greatly complicating the reconstruction task. Many of these errors result in distance measurements that can be safely assumed to lie within certain fixed tolerances. But a number of sources of systematic error in these experiments lead to inaccuracies in the data that are very hard to quantify; in effect, one must treat certain entries of the measured distance matrix as being arbitrarily “corrupted.”The existence of arbitrary errors leads to an interesting sort of error-correction problem—how many corrupted entries in a distance matrix can be efficiently corrected to produce a consistent three-dimensional structure? For the case of an n × n matrix in which every entry is specified, we provide a randomized algorithm running in time O(n log n) that enumerates all structures consistent with at most (1/2-e)n errors per row, with high probability. In the case of randomly located errors, we can correct errors of the same density in a sparse matrix-one in which only a b fraction of the entries in each row are given, for any constant bgt;0.
On the determinants of inequality in Bosnia and Herzegovina

We provide empirical evidence on the determinants of income inequality in Bosnia and Herzegovina after the civil war. To do this, we use a an ordered probit approach and take advantage of the first post-war household survey for the country which sheds some light on the influence of regional differences as well as household characteristics on income quintile determination. With respect to the former, we find large income differences between the two entities in the country, the Federation and Republika Srpska. Such income differences are also noticeable inside entities. On the latter, there are some signs that education, experience, and employment, among others, may help reduce the probability of income decline. Our results are robust to changes of specification as shown by applying a formal sensitivity analysis. JEL classification: O15, O10, I30.
Formation of AlN and GaN nanocolumns on Si(111) using molecular beam epitaxy with ammonia as a nitrogen source

We have demonstrated growth of AlN and GaN nanocolumns using molecular beam epitaxy with ammonia as a nitrogen source. The appearance of the columnar structure is correlated with the use of a low-temperature AlN buffer layer, grown at about 650 oC. Field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) indicate that the column diameters range from 12 to 30 nm. Layers were grown on Si(111) substrates with a variety of AlN buffer layer growth conditions. The AlN columns are distinct though tightly packed, and the tips of the columns are separated. Large, platelet-like protrusions are observed for low growth temperatures. Results from X-ray diffraction (XRD) and low-temperature photoluminescence (PL) are also discussed. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Budget Balancedness and Optimal Income Taxation

We make two main contributions to the theory of optimal income taxation. First, assuming conditions sufficient for existence of a Pareto optimal income tax and public goods mechanism, we show that if agents’ preferences satisfy an extended notion of single crossing called capacity constrained single crossing, then there exists a Pareto optimal income tax and public goods mechanism that is budget balancing. Second, we show that, even without capacity constrained single crossing, existence of a budget balancing, Pareto optimal income tax and public goods mechanism is guaranteed if the set of agent types contains no atoms.
A Practical Approach to Homo Trialkyl Phosphonates: A Catalytic Michaelis-Arbuzov Reaction

Homo trialkyl phosphonates are efficiently prepared by iodine catalyzed isomerization of the correspondind homo trialkyl phosphites. The product is isolated by simple distillation.
A Stereochemical Model for Merged 1,2- and 1,3-Asymmetric Induction in Diastereoselective Mukaiyama Aldol Addition Reactions and Related Processes

A systematic investigation of the direction and degree of stereoselectivity in aldol addition reactions is presented involving achiral unsubstituted metal enolate and enolsilane nucleophiles and chiral aldehydes. The BF3·OEt2 mediated Mukaiyama aldol reaction with α-unsubstituted, β-alkoxy aldehydes afforded good levels of 1,3-anti induction in the absence of internal aldehyde chelation. The level of 1,3-induction was found to be primarily dependent on the electrostatic nature of the aldehyde β-substituent. A revised model for 1,3-asymmetric induction is presented to account for these results based primarily on minimization of internal electrostatic and steric repulsion between the aldehyde carbonyl moiety and the β-substituents. A full conformational analysis, corroborated by semiempirical (AM1) calculations, is presented to support the proposed model. The merged impact of α and β aldehyde substituents was also systematically investigated, and an integrated 1,2- and 1,3-asymmetric induction model is prop...
Distributional effects of educational improvements :are we using the wrong model ?

Measuring the incidence of public spending in education requires an intergenerational framework distinguishing between what current and future generations - that is, parents and children - give and receive. In standard distributional incidence analysis, households are assumed to receive a benefit equal to what is spent on their children enrolled in the public schooling system and, implicitly, to pay a fee proportional to their income. This paper shows that, in an intergenerational framework, this is equivalent to assuming perfectly altruistic individuals, in the sense of the dynastic model, and perfect capital markets. But in practice, credit markets are imperfect and poor households cannot borrow against the future income of their children. The authors show that under such circumstances, standard distributional incidence analysis may greatly over-estimate the progressivity of public spending in education: educational improvements that are progressive in the long-run steady state may actually be regressive for the current generation of poor adults. This is especially true where service delivery in education is highly inefficient - as it is in poor districts of many developing countries - so that the educational benefits received are relatively low in comparison with the cost of public spending. The results have implications for both policy measures and analytical approaches.
Pink and Blue: Outcomes Associated with the Integration of Open Gay and Lesbian Personnel in the San Diego Police Department

We examine whether the integration of open gay and lesbian officers has undermined the organizational effectiveness of the San Diego Police Department (SDPD). Based on an analysis of prior research...
Properties of Cu in GaAs

The electrical properties and preferred lattice sites of Cu in GaAs were studied combining electrical and optical measurements with Particle Induced X-ray Emission (PIXE) and Channeling. For electronic characterization, Deep Level Transient Spectroscopy (DLTS), Hall Effect measurements, and Photoluminescence (PL) were used. From this comprehensive study it was determined that Cu introduces two levels in the bandgap, that the concentration of electrically active copper is considerably smaller than the total copper concentration, and that most of the Cu in GaAs is not of purely substitutional character.
Noncovalent Functionalization of Single-Walled Carbon Nanotubes

Single-walled carbon nanotubes (SWNTs) have attracted much attention on account of their potential to be transformed into new materials that can be employed to address a wide range of applications. The insolubility of the SWNTs in most solvents and the difficulties of handling these highly intractable carbon nanostructures, however, are restricting their real-life applications at the present time. To improve upon the properties of the SWNTs, low-cost and industrially feasible approaches to their modifications are constantly being sought by chemists and materials scientists. Together, they have shown that noncovalent functionalization of the SWNTs can do much to preserve the desired properties of the SWNTs while remarkably improving their solubilities. This Account describes recent advances in the design, synthesis, and characterization of SWNT hybrids and evaluates applications of these new hybrid materials based on noncovalently functionalized SWNTs. Their solubilization enables the characterization of t...
Holography and the Coleman-Mermin-Wagner theorem

In $2+1$ dimensions at finite temperature, spontaneous symmetry breaking of global symmetries is precluded by large thermal fluctuations of the order parameter. The holographic correspondence implies that analogous effects must also occur in $3+1$ dimensional theories with gauged symmetries in certain curved spacetimes with horizon. By performing a one loop computation in the background of a holographic superconductor, we show that bulk quantum fluctuations wash out the classical order parameter at sufficiently large distance scales. The low temperature phase is seen to exhibit algebraic long-range order. Beyond the specific example we study, holography suggests that IR singular quantum fluctuations of the fields and geometry will play an interesting role for many $3+1$ dimensional asymptotically anti--de Sitter spacetimes with planar horizon.
Spacecraft trajectory targeting by boundary-condition orbit fitting

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1984.
Stress Rupture in Ceramic-Matrix Composites: Theory and Experiment

A micromechanically based model for the deformation, strength, and stress-rupture life of a ceramic-matrix composite is developed for materials that do not degrade by oxidative attack. The rupture model for a unidirectional composite incorporates fiber-strength statistics, fiber degradation with time at temperature and load, the state of matrix damage, and the effects of fiber pullout, within a global load sharing model. The constituent material parameters that are required to predict the deformation and lifetime can all be obtained independent of stress-rupture testing through quasi-static tension tests and tests on the individual composite constituents. The model predicts the tertiary creep, the remaining composite strength, and the rupture life, all of which are dependent critically, on the underlying fiber-strength degradation. Sensitivity, of the rupture life to various micromechanical parameters is studied parametrically,. To complement the model, an extensive experimental study of stress rupture in a Nextel 610/alumina-yttria composite at temperatures of 950degrees and 1050degreesC is reported. The Larson-Miller and Monkman-Grant life-prediction methods are inadequate to explain the current data. Constituent parameters for this material system are derived from quasi-static tests and literature data, and the micromechanical model predictions are compared with measured behavior. For a slow-crack-growth model of fiber-strength degradation, the lifetime predictions are shorter by two orders of magnitude. When the rupture life is fitted with one parameter, however, the model prediction of the tertiary creep and residual strength at 1050degreesC agrees well with the experimental results. For a more complex degradation model, the rupture life and tertiary creep at 1050degreesC can be predicted quite well; however, the spread in residual strength is not, and the lifetimes at 950degreesC are greatly overpredicted. Thus, the micromechanical model can be successful quantitatively but clearly shows that the rupture life of the composite is extremely sensitive to the detailed mechanisms of fiber degradation. The model has practical applications for extrapolating laboratory lifetime data and predicting life in components with evolving spatial stresses.
Radical cystectomy for high risk patients with superficial bladder cancer in the era of orthotopic urinary reconstruction

Background. Many patients with aggressive clinically superficial bladder cancer ultimately die of their cancer, due in part to resistance to undergo radical cystectomy. Radical cystectomy is usually curative for patients with pathologic superficial tumors. Orthotopic urinary reconstruction has lessened the morbidity and life-style changes in patients after cystectomy, and may increase patient acceptance of cystectomy as therapy for high risk superficial tumors. Methods. A retrospective analysis was performed on 182 patients with clinically superficial bladder cancer (Ta, Tis, T1) who had radical cystectomy between 1971 and 1989, to determine the incidence of pathologic upstaging and to assess overall survival, cause-specific survival, and recurrence free survival. Indications for cystectomy included failure of intravesical chemo- or immunotherapy, high grade lamina propria invasive tumors, presence of bladder diverticulae, spread of superficial tumors into the prostatic urethra, and endoscopically uncontrollable tumors. Results. Pathologic upstaging to muscle-invasive or metastatic tumors occurred in 34% of patients, and of these, only half remained organ confined. Metastases were present in 8% of patients at the time of cystectomy. Mucosa-confined tumors were upstaged only 19% of the time, whereas tumors demonstrating lamina propria invasion (T1) were upstaged 40% of the time. Pathologic upstaging to muscle-invasive or metastatic disease was significantly associated with a decreased probability of survival (P = 0.042). With a median follow-up of 7.2 years, overall survival was estimated to be 86%, 72%, and 47%, and recurrence free survival 90%, 83%, and 77% at 2, 5, and 10 years, respectively. Conclusions. Pathologic upstaging to muscle-invasive or metastatic tumors occurs in one third of highly selected patients with clinically superficial bladder cancer who have had radical cystectomy, half of whom have extravesical disease. Survival is significantly decreased in this group of upstaged patients. With the alternative of orthotopic urinary diversion available to most men and women requiring cystectomy, radical cystectomy should be considered a viable alternative to continued conservative measures for selected patients with aggressive superficial bladder tum.
Embracing interference in ad hoc networks using joint routing and scheduling with multiple packet reception

We present an approach that takes advantage of multi-packet reception (MPR) to reduce the negative effects of multiple access interference and therefore increase the capacity of an ad hoc network. We analyze the performance upper bound of joint routing and scheduling for ad hoc networks that embrace interference by using MPR. We formulate the optimization problem under a deterministic model and seek to maximize the aggregate network throughput subject to minimum rate requirements. We then propose a polynomial-time heuristic algorithm aimed at approximating the optimal solution to the joint routing and channel access problem under MPR. We show the effectiveness of our heuristic algorithm by comparing its performance with the upper bound.
Near-optimal mean - variance controls under two-time-scale formulations and applications

Although the mean–variance control was initially formulated for financial portfolio management problems in which one wants to maximize the expected return and control the risk, our motivations stem from highway vehicle platoon controls that aim to maximize highway utility while ensuring zero accident. This paper develops near-optimal mean–variance controls of switching diffusion systems. To reduce the computational complexity, with motivations from earlier work on singularly perturbed Markovian systems [Sethi and Zhang, Hierarchical Decision Making in Stochastic Manufacturing Systems, Birkhauser, Boston, MA, 1994; Yin and Zhang, Continuous-Time Markov Chains and Applications: A Singular Pertubation Approach, Springer-Verlag, New York, 1998 and Yin et al., Ann. Appl. Probab. 10 (2000), pp. 549–572], we use a two-time-scale formulation to treat the underlying system, which is represented by the use of a small parameter. As the small parameter goes to 0, we obtain a limit problem. Using the limit problem as ...
Discovering thread interactions in a concurrent system

Understanding the behavior of a system is a central reverse engineering task, and is crucial for being able to modify, maintain, and improve the system. An often difficult aspect of some system behaviors is concurrency, in particular identifying those areas that exhibit mutual exclusion and those that exhibit synchronization. In this paper we present a technique that builds on our previous work in behavior discovery to find the points in the system that demonstrate mutually exclusive and synchronized behavior. Finding these points in the behavior of the system is an important aid in reverse engineering a complete and correct model of the system.
Discovery of a novel function for human Rad51: Maintenance of the mitochondrial genome

Homologous recombination (HR) plays a critical role in facilitating replication fork progression when the polymerase complex encounters a blocking DNA lesion, and it also serves as the primary mechanism for error-free repair of DNA double strand breaks. Rad51 is the central catalyst of HR in all eukaryotes, and to this point studies of human Rad51 have focused exclusively on events occurring within the nucleus. However, substantial amounts of HR proteins exist in the cytoplasm, yet the function of these protein pools has not been addressed. Here, we provide the first demonstration that Rad51 and the related HR proteins Rad51C and Xrcc3 exist in human mitochondria. We show stress-induced increases in both the mitochondrial levels of each protein and, importantly, the physical interaction between Rad51 and mitochondrial DNA (mtDNA). Depletion of Rad51, Rad51C, or Xrcc3 results in a dramatic decrease in mtDNA copy number as well as the complete suppression of a characteristic oxidative stress-induced copy number increase. Our results identify human mtDNA as a novel Rad51 substrate and reveal an important role for HR proteins in the maintenance of the human mitochondrial genome.
Microstrip gas chamber on thin-film Pestov glass and micro gap chamber

We report developments of the microstrip gas chamber on thin-film Pestov glass and the micro gap chamber. By coating a thin-layer of low-resistive, electronically-conductive glass on various substrates (including quartz and ceramics), we built MSGCs of high gain stability and low leakage current. They were tested in ArCH4(10%) and HeC2H6(50%) gas mixtures. Energy resolutions of 17–20% were measured for 6 keV X-rays. This design can make the choice of substrate less important, save the cost of ion-implantation, and use less glass material. Micro Gap Chamber was successfully tested in HeC2H6(50%) and ArC2H6(50%) gas mixtures. Energy resolutions of about 20% were obtained. Both detectors are expected to have high rate capability.
Arcjet flow properties determined from laser-induced fluorescence of atomic nitrogen

Flow property measurements that were recently acquired in the Ames Research Center Aerodynamic Heating Facility arcjet using two-photon laser-induced fluorescence (LIF) of atomic nitrogen (N) are reported. The flow properties, which include velocity, translational temperature, and N concentration, were measured simultaneously over a range of facility operating conditions for N2–argon test gas flows in the 30-cm-diameter nozzle. A recent measurement of the two-photon excitation cross section for the 3p4D° ← 2p4S° transition of atomic nitrogen is used to convert the relative nitrogen concentration measurements to absolute values, and a nitrogen flow reactor is used to provide a room-temperature, reference-wavelength calibration of the translational temperature and velocity measurements. When combined with information from facility measurements, an analysis of the flow properties obtained using two-photon LIF of N yields the total free-stream flow enthalpy.
The New Issues Puzzle: Testing the Investment-Based Explanation

An investment factor, long in low-investment stocks and short in high-investment stocks, helps explain the new issues puzzle. Adding the investment factor into standard factor regressions reduces the SEO underperformance by about 75%, the IPO underperformance by 80%, the underperformance following convertible debt offerings by 50%, and Daniel and Titman’s (2006) composite issuance effect by 40%. The reason is that issuers invest more than nonissuers, and the investment factor earns a significantly positive average return of 0.57% per month. Equity and debt issuers underperform matching nonissuers with similar characteristics in the post-issue years (e.g., Ritter, 1991; Loughran and Ritter, 1995; and Spiess and Affleck-Graves, 1995, 1999). We explore empirically the investment-based hypothesis of this underperformance. The q-theory of investment and the real options theory imply a negative relation between real investment and expected returns. If the proceeds from equity and debt issues are used to finance investment, then issuers should invest more and earn lower average returns than matching nonissuers.
A framework for multi-object tracking over distributed wireless camera networks

In this paper, we propose a unified framework targeting at two important issues in a distributed wireless camera network, i.e., object tracking and network communication, to achieve reliable multi-object tracking over distributed wireless camera networks. In the object tracking part, we propose a fully automated approach for tracking of multiple objects across multiple cameras with overlapping and non-overlapping field of views without initial training. To effectively exchange the tracking information among the distributed cameras, we proposed an idle probability based broadcasting method, iPro , which adaptively adjusts the broadcast probability to improve the broadcast effectiveness in a dense saturated camera network. Experimental results for the multi-object tracking demonstrate the promising performance of our approach on real video sequences for cameras with overlapping and non-overlapping views. The modeling and ns-2 simulation results show that iPro almost approaches the theoretical performance upper bound if cameras are within each other's transmission range. In more general scenarios, e.g., in case of hidden node problems, the simulation results show that iPro significantly outperforms standard IEEE 802.11, especially when the number of competing nodes increases.
Rigidity Theorems for Compact Manifolds with Boundary and Positive Ricci Curvature

We prove some boundary rigidity results for the hemisphere under a lower bound for Ricci curvature. The main result can be viewed as the Ricci version of a conjecture of Min-Oo.
Video classification in user profile generation for personalized broadcast services

Automatic generation of user profiles, as specified in the MPEG-7 user preference description scheme, for personized broadcast services is investigated in this work. Our research has focused on categorization of user-favored video into different semantically meaningful classes. This knowledge is then used in media filtering guidance and user preferred AV content selection. Several visual and motion features are extracted from source video sequences, such as the number of intra-coded macroblocks, the macroblock motion information, temporal variances and shot activity histograms, for the classification purposes. Moreover, to further improve the accuracy of classification results, a 'fuzzy nearest prototype classifier' is applied in this work. It is shown by experimental results that the proposed classification scheme is efficient and accurate.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Thermochemistry of alkali interactions with refractory adsorbents

Abstract The kinetics and mechanism of interactions between alkali vapors and several refractory adsorbents are studied. A unique thermogravimetric reactor is designed and utilized for this study. Bauxite and kaolin are very good adsorbents for alkali chlorides and are potentially good additives for control of alkali during coal combustion and gasification. The experimental data shows that the alkali capturing process is a combination of physisorption, chemisorption and chemical reaction. An analytical model is developed assuming a multi-layer adsorption of alkali on substrate followed by a rate-controlling reaction on the surface. The experimental results and model predictions are in good agreement.
Cell cycle: The bacterial approach to coordination

Despite the power of bacterial genetics, the prokaryotic cell cycle has remained poorly understood. But recent work with three different bacterial species has shed light on how chromosomes and plasmids are oriented and partitioned during the cell cycle, and on mechanisms regulating the initiation of DNA replication.
Integral Theory for Supersonic Turbulent Base Flows

The integral near- wake analysis of Reeves and Lees developed for supersonic laminar base flows with viscous-inviscid interaction is extended to the case of fully turbulent separated adiabatic flow behind a rearward-facin g step at supersonic speeds. A turbulent eddy viscosity model is formulated for the shear stress scaling of the dissipation integral in the mechanical energy equation. It is shown that the eddy viscosity can be described simply by one incompressible constant (valid for both shear layers and wakes) and one reference density pr. Using a compressibility transformation, theoretical solutions for the spreading rates of free shear layers are found to agree with experiment when the reference density is chosen to be the centerline density for the wake flow. The wake flow solution, uniquely determined by the wake critical point, is joined to the body through a turbulent free shear layer mixing solution. A simple conservation model is presented to relate the viscous sublayer after expansion to the initial boundary layer ahead of the step. For freestream Mach numbers MI < 2.3, where lip shock effects may be neglected, the integral theory is found to give good estimates for the length scales and centerline pressure variations measured experimentally for both wake flows and step flows (where reattachment is to a solid surface). b C f f'M h
Global phase diagram of bilayer quantum Hall ferromagnets

We present a microscopic study of the interlayer spacing d versus in-plane magnetic field ${B}_{\ensuremath{\Vert}}$ phase diagram for bilayer quantum Hall (QH) pseudoferromagnets. In addition to the interlayer charge balanced commensurate and incommensurate states analyzed previously, we address the corresponding interlayer charge unbalanced ``canted'' QH states. We predict a large anomaly in the bilayer capacitance at the canting transition and the formation of dipole stripe domains with periods exceeding 1 micron in the canted state.
New results on the Stieltjes constants: Asymptotic and exact evaluation

Abstract The Stieltjes constants γ k ( a ) are the expansion coefficients in the Laurent series for the Hurwitz zeta function about s = 1 . We present new asymptotic, summatory, and other exact expressions for these and related constants.
Iwasawa invariants of galois deformations

Fix a residual ordinary representation Open image in new window :GF→GLn(k) of the absolute Galois group of a number field F. Generalizing work of Greenberg–Vatsal and Emerton–Pollack–Weston, we show that the Iwasawa invariants of Selmer groups of deformations of Open image in new window depends only on Open image in new window and the ramification of the deformation.
PRODUCT QUALITY AND MARKET SIZE

Do larger markets offer better products? The question has implications for theories of cities and theories of market organization. We document that in the restaurant industry, where quality is produced largely with variable costs, the range of qualities on offer increases in market size. In daily newspapers, where quality is produced with fixed costs, the average quality of products increases with market size, but the market does not offer much additional variety as it grows large. These results are consistent with IO theories of endogenous product quality and with theories that emphasize the consumption advantages of cities.
New reagents for phosphatidylserine recognition and detection of apoptosis

The phospholipid bilayer surrounding animal cells is made up of four principle phospholipid components, phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS), and sphingomyelin (SM). These four phospholipids are distributed between the two monolayers of the membrane in an asymmetrical fashion, with PC and SM largely populating the extracellular leaflet and PE and PS restricted primarily to the inner leaflet. Breakdown in this transmembrane phospholipid asymmetry is a hallmark of the early to middle stages of apoptosis. The consequent appearance of PS on the extracellular membrane leaflet is commonly monitored using dye-labeled Annexin V, a 36 kDa, Ca2+-dependent PS binding protein. Substitutes for Annexin V are described, including small molecules, nanoparticles, cationic liposomes, and other proteins that can recognize PS in a membrane surface. Particular attention is given to the use of these reagents for detecting apoptosis.
Designing information structures for quadratic decision problems

This paper investigates the problem of unconstrained optimization when there is only partial information on the random parameters in the objective function. The relation between the optimization performance and the available information is established. The best information structure design with fixed rank is described. The designing procedure is set up in such a way that successive information augmentation or deletion can be considered. The procedure can also be extended to multiperson decision problems.
CATALYTIC OXIDATION OF ALKENES WITH A SURFACE-BOUND METALLOPORPHYRIN-PEPTIDE CONJUGATE

Abstract A novel surface-bound metalloporphyrin-peptide conjugate was prepared and used to catalytically oxidize alkenes in the presence of iodosylbenzene. The catalyst was found to oxidize a number of alkene substrates in good yield under a variety of reaction conditions. Comparison to control experiments using surface-bound Mn(III)tetraphenylporphyrin showed differences in oxidation yields and ratios of oxidized products. Substrate competition experiments demonstrated the ability of the conjugate catalyst to discriminate between substrates on the basis of size. Both results suggest oxidative catalysis occurred between the porphyrin ring and the peptide chain with the peptide influencing the outcome of the reaction in accord with the catalyst design.
Dualities in Supersymmetric Field Theories

These lectures 1 briefly introduce dualities in four-dimensional quantum field theory, and summarize results found in supersymmetric field theories. The first lecture describes physical aspects of electric-magnetic (EM), strong-weak coupling (S), and infrared (IR) dualities. The second lecture focuses on results and conjectures concerning S-duality in N =2 supersymmetric gauge theories. The third lecture discusses IR-dualities and their relation to S-duality in N =1 supersymmetric field theories.
Control Systems for Automotive Vehicle Fuel Economy: A Literature Review

This paper is a review of current research on applications of control systems and theory to achieve energy conservation in automotive vehicles. The development of internal combustion engine control systems that modulate fuel flow, air flow, ignition timing and duration, and exhaust gas recirculation is discussed. The relative advantages of physical and empirical models for engine performance are reviewed. Control strategies presented include optimized open-loop schedule type systems, closed-loop feedback systems, and adaptive controllers. The development of power train and hybrid vehicle control systems is presented, including controllers for both conventional transmissions and those employing flywheel energy storage.
AVOIDING SPURIOUS BREAKS IN BINNED LUMINOSITY FUNCTIONS

We show that using either the method of Page & Carrera or the well-known -->1/Va method to construct the binned luminosity function (LF) of a flux limited sample of active galactic nuclei (AGNs) can produce an artificial flattening (or steepening in the case of negative evolution) of the binned LF for bins intersected by the flux cutoff of the sample. This effect is more pronounced for samples with steep and strongly evolving parent LFs but is still present even for non-evolving LFs. As a result of this distortion of the true LF, fitting a model LF to binned data may lead to errors in the estimation of the parameters and may even prompt the erroneous use of broken power-law functions. We compute the expected positions of apparent breaks in the binned LF. We show that these spurious breaks in the binned LFs can be avoided if the binning is done in the flux-redshift plane instead of the typically used luminosity-redshift plane. Binning in the flux-redshift plane can be used in conjunction with the binning in the luminosity-redshift plane to test for real breaks in the binned LFs and to identify the features that are the result of binning biases. We illustrate this effect for most typical forms of luminosity dependence and redshift evolution and show how the proposed method helps address this problem. We also apply this method to the MOJAVE AGN sample and show that it eliminates an apparent break in the binned LF.
Picosecond Optical Switching Based on Biphotonic Excitation of an Electron Donor-Acceptor-Donor Molecule

An electron donor-acceptor-donor molecule consisting of two porphyrin donors rigidly attached to the two-electron acceptor N,N'-diphenyl-3,4,9,10-perylenebis(dicarboximide) acts as a light intensity-dependent molecular switch on a picosecond time scale. Excitation of the porphyrins within this molecule with subpicosecond laser pulses results in single or double reduction of the acceptor depending on the light intensity. The singly and doubly reduced electron acceptors absorb light strongly at 713 and 546 nanometers, respectively. Because these absorption changes are produced solely by electron transfers, this molecular switch effectively has no moving parts and switches significantly faster than photochromic molecules that must undergo changes in molecular structure.
Catalytic Asymmetric Synthesis of Allylic Thiol Derivatives

The palladium(II) complex [(Rp,S)-COP-Cl]2 and its enantiomer catalyze the rearrangement of linear prochiral O-allyl carbamothioates under mild conditions to provide branched S-allyl carbamothioates in high yield and high enantiomeric purity.
Enhancing performance of particle swarm optimization through an algorithmic link with genetic algorithms

Evolutionary Algorithms (EAs) are emerging as competitive and reliable techniques for several optimization tasks. Juxtapositioning their higher-level and implicit correspondence; it is provocative to query if one optimization algorithm can benefit from another by studying underlying similarities and dissimilarities. This paper establishes a clear and fundamental algorithmic linking between particle swarm optimization (PSO) algorithm and genetic algorithms (GAs). Specifically, we select the task of solving unimodal optimization problems, and demonstrate that key algorithmic features of an effective Generalized Generation Gap based Genetic Algorithm can be introduced into the PSO by leveraging this algorithmic linking while significantly enhance the PSO's performance. However, the goal of this paper is not to solve unimodal problems, neither is to demonstrate that the modified PSO algorithm resembles a GA, but to highlight the concept of algorithmic linking in an attempt towards designing efficient optimization algorithms. We intend to emphasize that the evolutionary and other optimization researchers should direct more efforts in establishing equivalence between different genetic, evolutionary and other nature-inspired or non-traditional algorithms. In addition to achieving performance gains, such an exercise shall deepen the understanding and scope of various operators from different paradigms in Evolutionary Computation (EC) and other optimization methods.
Iterated Class Forcing

In this paper we isolate the notion of Stratified class forcing and show that Stratification implies cofinality-preservation and is preserved by iterations with the appropriate support. Many familiar class forcings are stratified and therefore can be simultaneously iterated without changing cofinalities, provided the proper support is used. Easton forcing, Backward Easton forcings and some modifications of Jensen coding are stratified. Jensen coding is not stratified but instead obeys a related property, Delta-Stratification, which is also preservedby iteration with an appropriate larger support.
A FAMILY OF CHAOTIC BILLIARDS WITH VARIABLE MIXING RATES

We describe a one-parameter family of dispersing (hence hyperbolic, ergodic and mixing) billiards where the correlation function of the collision map decays as 1/na (here n denotes the discrete time), in which the degree a ∈ (1, ∞) changes continuously with the parameter of the family, β. We also derive an explicit relation between the degree a and the family parameter β.
The Hawking Effect for Massive Particles

This paper describes a particularly transparent derivation of the Hawking effect for massive particles in black holes. The calculations are performed with the help of Painleve-Gullstrand’s coordinates which are associated with a radially free-falling observer that starts at rest from infinity. It is shown that if the energy per unit rest mass, e, is assumed to be related to the Killing constant, k, by k2 = 2e – 1 then e, must be greater than ½. For particles that are confined below the event horizon (EH), k is negative. In the quantum creation of particle pairs at the EH with k = 1, the time component of the particle’s four velocity that lies below the EH is compatible only with the time component of an outgoing particle above the EH, i.e, the outside particle cannot fall back on the black hole. Energy conservation requires that the particles inside, and outside the EH has the same value of e, and is created at equal distances from the EH, (1 – rin = rout – 1). Global energy conservations force then the mass of the particle below the EH to be negative, and equal to minus the mass the particle above the EH, i.e., the black hole looses energy as a consequence of pair production.
Synthesis of amine functionalized oxazolines with applications in asymmetric catalysis

This paper describes the synthesis of three classes of amine functionalized oxazolines that have been successfully used in asymmetric catalysis in our laboratory. Failed synthetic routes and significantly improved procedures are discussed including the synthesis of ligands for Nozaki–Hiyama–Kishi (NHK) carbonyl allylation reactions that do not require chromatography for purification.
Delaunay meshing of isosurfaces

We present an isosurface meshing algorithm, DelIso, based on the Delaunay refinement paradigm. This paradigm has been successfully applied to mesh a variety of domains with guarantees for topology, geometry, mesh gradedness, and triangle shape. A restricted Delaunay triangulation, dual of the intersection between the surface and the three-dimensional Voronoi diagram, is often the main ingredient in Delaunay refinement. Computing and storing three-dimensional Voronoi/Delaunay diagrams become bottlenecks for Delaunay refinement techniques since isosurface computations generally have large input datasets and output meshes. A highlight of our algorithm is that we find a simple way to recover the restricted Delaunay triangulation of the surface without computing the full 3D structure. We employ techniques for efficient ray tracing of isosurfaces to generate surface sample points, and demonstrate the effectiveness of our implementation using a variety of volume datasets.