cssi/SciSciGPT-SciSciNet huggingface dataset:
Perspectives on the synthesis and application of triple-helical, collagen-model peptides

Collagens can be distinguished from other proteins based on their triple-helical structure. Synthetic peptide models have been developed to better understand the triple helix structurally and to evaluate the triple helix as a recognition element for biological processes. Associated triple-helical peptides were first designed and assembled by solid-phase methodology in the late 1960s. Such peptides were used for triple-helical structural characterization by CD, nmr, and ir spectroscopies, and x-ray crystallography, and for studying the structural preferences of hydroxylases. In the late 1970s, methods were developed for covalently linking the three strands of triple-helical peptides. One benefit of "branched" peptides was the enhancement of triple-helical thermal stability. The incorporation of specific collagen sequences into thermally stable synthetic triple helices in the early 1990s has allowed for the mechanistic investigation of collagen-mediated cell adhesion and platelet aggregation. In time, discriminatory therapeutics may result from the continued exploration and further understanding of the biological effects of collagen primary, secondary, and tertiary structures via triple-helical peptide models.
Improving model understanding using statistical screening

Models of dynamic systems are often constructed to improve system performance by identifying and modifying structures and parameters that drive system behavior. Once identified, these can be used to design and test policies for performance improvement. A preliminary step in developing policies is the identification of high leverage parameters and structures, the influential model sections that drive system behavior. The current work describes the use of statistical screening as a tool to improve model understanding, explanation, and development with a six step process. Statistical screening offers system modelers a user-friendly tool that can be used to help explain how model structure drives behavior.
Existence and Uniqueness for a Class of Nonlinear Higher-Order Partial Differential Equations in the Complex Plane

We prove existence and uniqueness results for nonlinear third-order partial differential equations of the form
Costs, Effectiveness, and Workload Impact of Management Strategies for Women With an Adnexal Mass

Background We compared the estimated clinical outcomes, costs, and physician workload resulting from available strategies for deciding which women with an adnexal mass should be referred to a gynecologic oncologist. Methods We used a microsimulation model to compare five referral strategies: 1) American Congress of Obstetricians and Gynecologists (ACOG) guidelines, 2) Multivariate Index Assay (MIA) algorithm, 3) Risk of Malignancy Algorithm (ROMA), 4) CA125 alone with lowered cutoff values to prioritize test sensitivity over specificity, 5) referral of all women (Refer All). Test characteristics and relative survival were obtained from the literature and data from a biomarker validation study. Medical costs were estimated using Medicare reimbursements. Travel costs were estimated using discharge data from Surveillance, Epidemiology and End Results-Medicare and State Inpatient Databases. Analyses were performed separately for pre- and postmenopausal women (60 000 "subjects" in each), repeated 10 000 times. Results Refer All was cost-effective compared with less expensive strategies in both postmenopausal (incremental cost-effectiveness ratio [ICER] $9423/year of life saved (LYS) compared with CA125) and premenopausal women (ICER $10 644/YLS compared with CA125), but would result in an additional 73 cases/year/subspecialist. MIA was more expensive and less effective than Refer All in pre- and postmenopausal women. If Refer All is not a viable option, CA125 is an optimal strategy in postmenopausal women. Conclusions Referral of all women to a subspecialist is an efficient strategy for managing women with adnexal masses requiring surgery, assuming sufficient capacity for additional surgical volume. If a test-based triage strategy is needed, CA125 with lowered cutoff values is a cost-effective strategy.
Cargill's acquisition of Continental Grain's grain merchandising business

What are the advantages of concerns raised regarding the Cargill acquisition of Continental Grain company's grain merchandising business? The largest grain exporter acquiring the second largest exporter has raised some concerns regarding potential loss of competition, but also may make these firms with excess capacity more efficient and effective in competing for a larger U.S. share of the world market. This white paper pulls together the relevant data which was quickly available and provides some analysis which may prove useful in the dialog as the pros and cons of this acquisition are debated.
The travel and environmental implications of shared autonomous vehicles, using agent-based model scenarios

Abstract Carsharing programs that operate as short-term vehicle rentals (often for one-way trips before ending the rental) like Car2Go and ZipCar have quickly expanded, with the number of US users doubling every 1–2 years over the past decade. Such programs seek to shift personal transportation choices from an owned asset to a service used on demand. The advent of autonomous or fully self-driving vehicles will address many current carsharing barriers, including users’ travel to access available vehicles. This work describes the design of an agent-based model for shared autonomous vehicle (SAV) operations, the results of many case-study applications using this model, and the estimated environmental benefits of such settings, versus conventional vehicle ownership and use. The model operates by generating trips throughout a grid-based urban area, with each trip assigned an origin, destination and departure time, to mimic realistic travel profiles. A preliminary model run estimates the SAV fleet size required to reasonably service all trips, also using a variety of vehicle relocation strategies that seek to minimize future traveler wait times. Next, the model is run over one-hundred days, with driverless vehicles ferrying travelers from one destination to the next. During each 5-min interval, some unused SAVs relocate, attempting to shorten wait times for next-period travelers. Case studies vary trip generation rates, trip distribution patterns, network congestion levels, service area size, vehicle relocation strategies, and fleet size. Preliminary results indicate that each SAV can replace around eleven conventional vehicles, but adds up to 10% more travel distance than comparable non-SAV trips, resulting in overall beneficial emissions impacts, once fleet-efficiency changes and embodied versus in-use emissions are assessed.
Success in Difficult Environments : A Portfolio Analysis of Fragile and Conflict-Affected States

The World Bank Group has identified support to fragile and conflict-affected states as a strategic priority. This paper provides a systematic portfolio review of the International Development Association-funded projects in fragile and conflict-affected states during 2001 to 2013 and a detailed empirical analysis of the correlations between project and country-level characteristics with project outcome ratings. The portfolio review identifies a decline in the proportional amount of resources directed to fragile and conflict-affected states and a decline in the number of internationally recruited staff based in these countries. The empirical analysis finds no statistical difference in whether projects obtain at least a moderately satisfactory outcome rating between countries that are fragile and conflict-affected states and those that are not. Examination of the distribution of project outcome ratings indicates that projects in fragile and conflict-affected states obtain slightly lower ratings conditional on being unsatisfactory or satisfactory. Detailed cross-section regression analysis finds that indicators of project complexity, such as supervision costs, staff time, preparation time, and financing, are correlated with lower outcome ratings. Project leader characteristics are correlated with project outcome ratings, but to a lesser degree in fragile and conflict-affected states, potentially indicating that it is more difficult for project leaders to influence project outcomes in these environments. Last, a new approach to control for unobservable project characteristics, such as inherent complexity or ambition, shows preliminary evidence that changes in the project leader and increases in the supervision budget are correlated with improvements in project performance.
On orbital period changes in nova outbursts

We propose a new mechanism that produces an orbital period change during a nova outburst. When the ejected material carries away the specific angular momentum of the white dwarf, the orbital period increases. A magnetic field on the surface of the secondary star forces a fraction of the ejected material to corotate with the star, and hence the binary system. The ejected material thus takes angular momentum from the binary orbit and the orbital period decreases. We show that for sufficiently strong magnetic fields on the surface of the secondary star, the total change to the orbital period could even be negative during a nova outburst, contrary to previous expectations. Accurate determinations of pre- and post-outburst orbital periods of recurrent nova systems could test the new mechanism, in addition to providing meaningful constraints on otherwise difficult to measure physical quantities. We apply our mechanism to outbursts of the recurrent nova U Sco.
Use of group 4 bis(sulfonamido) complexes in the intramolecular hydroamination of alkynes and allenes.

Titanium tetrakis(amido) complexes catalyze the intramolecular hydroamination of alkynes and allenes more efficiently than Cp-based species. We report here that electron-withdrawing and sterically demanding bis(sulfonamido) ligands lead to enhanced catalytic activity. Zirconium analogues have also been prepared, and the tosyl-substituted complex 20 has been structurally characterized. As in the titanium series, bis(sulfonamido) zirconium catalysts are more efficient in the intramolecular hydroamination of allenes than bis(cyclopentadienyl) complex Cp2ZrMe2 (23). Furthermore, these compounds transform 1,3-disubstituted aminoallenes with high stereoselectivity to the Z-allylamines and allow the hydroamination of a trisubstituted allene. Titanium bis(sulfonamido) imido complex 27 was synthesized. It converts aminoallene 10 to cylic imine 11 with a rate comparable to that of tetrakis(amide) 15, supporting the hypothesis of a catalytically active titanium imido intermediate.
Complex formation by the human Rad51B and Rad51C DNA repair proteins and their activities in vitro

The human Rad51 protein is essential for DNA repair by homologous recombination. In addition to Rad51 protein, five paralogs have been identified: Rad51B/Rad51L1, Rad51C/Rad51L2, Rad51D/Rad51L3, XRCC2, and XRCC3. To further characterize a subset of these proteins, recombinant Rad51, Rad51B-(His)(6), and Rad51C proteins were individually expressed employing the baculovirus system, and each was purified from Sf9 insect cells. Evidence from nickel-nitrilotriacetic acid pull-down experiments demonstrates a highly stable Rad51B.Rad51C heterodimer, which interacts weakly with Rad51. Rad51B and Rad51C proteins were found to bind single- and double-stranded DNA and to preferentially bind 3'-end-tailed double-stranded DNA. The ability to bind DNA was elevated with mixed Rad51 and Rad51C, as well as with mixed Rad51B and Rad51C, compared with that of the individual protein. In addition, both Rad51B and Rad51C exhibit DNA-stimulated ATPase activity. Rad51C displays an ATP-independent apparent DNA strand exchange activity, whereas Rad51B shows no such activity; this apparent strand exchange ability results actually from a duplex DNA destabilization capability of Rad51C. By analogy to the yeast Rad55 and Rad57, our results suggest that Rad51B and Rad51C function through interactions with the human Rad51 recombinase and play a crucial role in the homologous recombinational repair pathway.
Impact experiments in low-temperature ice

New results of low-velocity impact experiments in cubic and cylindrical (20 cm) water-ice targets initially at 257 and 81 °K are reported. Impact velocities and impact energies vary between 0.1 and 0.64 km/sec and 10^9 and 10^(10) ergs, respectively. Observed crater diameters range from 7 to 15 cm and are two to three times larger than values found for equal-energy impacts in basaltic targets. Crater dimensions in ice targets increase slightly with increasing target temperatures. Crater volumes of strength-controlled ice craters are about 10 to 100 times larger than those observed for craters in crystalline rocks. Based on similarity analysis, general scaling laws for strength-controlled crater formation are derived and are applied to crater formation on the icy Galilean and Saturnian satellites. This analysis indicates that surface ages, based on impact-crater statistics on an icy crust, will appear greater than those for a silicate crust which experienced the same impact history. The greater ejecta volume for cratering in ice versus cratering in silicate targets leads to accelerated regolith production on an icy planet.
The island coalescence problem: Scaling of reconnection in extended fluid models including higher-order moments

As modeling of collisionless magnetic reconnection in most space plasmas with realistic parameters is beyond the capability of today's simulations, due to the separation between global and kinetic length scales, it is important to establish scaling relations in model problems so as to extrapolate to realistic scales. Recently, large scale particle-in-cell simulations of island coalescence have shown that the time averaged reconnection rate decreases with system size, while fluid systems at such large scales in the Hall regime have not been studied. Here, we perform the complementary resistive magnetohydrodynamic (MHD), Hall MHD, and two fluid simulations using a ten-moment model with the same geometry. In contrast to the standard Harris sheet reconnection problem, Hall MHD is insufficient to capture the physics of the reconnection region. Additionally, motivated by the results of a recent set of hybrid simulations which show the importance of ion kinetics in this geometry, we evaluate the efficacy of the ten-moment model in reproducing such results.
Detection of morphological markers of vulnerable atherosclerotic plaque using multimodal spectroscopy

Vulnerable plaques, which are responsible for most acute ischemic events, are presently invisible to x-ray angiography. Their primary morphological features include a thin or ulcerated fibrous cap, a large necrotic core, superficial foam cells, and intraplaque hemorrhage. We present evidence that multimodal spectroscopy MMS, a novel method that combines diffuse reflectance spectros- copy DRS, intrinsic fluorescence spectroscopy IFS, and Raman spectroscopy RS, can detect these markers of plaque vulnerability. To test this concept, we perform an MMS feasibility study on 17 hu- man carotid artery specimens. Following the acquisition of spectra, each specimen is histologically evaluated. Two parameters from DRS, hemoglobin concentration and a scattering parameter, are used to detect intraplaque hemorrhage and foam cells; an IFS parameter that relates to the amount of collagen in the topmost layers of the tissue is used to detect the presence of a thin fibrous cap; and an RS parameter related to the amount of cholesterol and necrotic material is used to detect necrotic core. Taken together, these spectral parameters can generally identify the vulnerable plaques. The results indicate that MMS provides depth-sensitive and complementary morphological in- formation about plaque composition. A prospective in vivo study will be conducted to validate these findings. © 2006 Society of Photo-Optical Instru-
Leading Indicators of Failure for Prognostication of Leaded and Lead-Free Electronics in Harsh Environments

In this paper, a methodology for prognostication-of-electronics has been developed for assessment of residual life in deployed electronic components, and the determination of damage-state in absence of macro-indicators of failure. Proxies for leading indicators-of-failure have been identified and correlated with damage progression under thermomechanical loads. Examples of proxies include micro-structural evolution characterized by average phase size and intermetallic growth rate in solder interconnects. Validity of damage proxies has been investigated for both 63Sn37Pb leaded and SnAgCu lead-free electronics. Structures examined include plastic ball grid array format electronic and MEMS packages and discrete devices assembled with FR4-06 laminates. The focus of the research presented in this paper is on interrogation of the aged material's damage state and enhancing the understanding of damage progression. Instead of life prediction of new components, the research is aimed at the development of damage relationships for determination of residual life of aged electronics and the assessment of design margins. The prognostic indicators presented in this paper can be used for health monitoring of electronic assemblies.
Spherical varieties and integral representations of L-functions

We present a conceptual and uniform interpretation of the methods of integral representations of L-functions (period integrals, Rankin–Selberg integrals). This leads to (i) a way to classify such integrals, based on the classification of certain embeddings of spherical varieties (whenever the latter is available), (ii) a conjecture that would imply a vast generalization of the method, and (iii) an explanation of the phenomenon of “weight factors” in a relative trace formula. We also prove results of independent interest, such as the generalized Cartan decomposition for spherical varieties of split groups over p-adic fields (following an argument of Gaitsgory and Nadler).
Multichip packaging technology with laser-patterned interconnects

A multichip silicon-on-silicon packaging technology has been developed which incorporates laser-patterned thin-film interconnects. This technology is particularly suited for application in high-speed, high-power, and high-I/O systems, where its unique characteristics provide many advantages over more traditional methods. The laser-patterned thin-film interconnects allow higher I/O densities and better electrical performance than wire bonds or TAB (tape automated bonding). The face-up, thin-film eutectic die attach technique used provides much lower thermal resistance between the substrate and the chips than can be achieved with solder bump die attach. In addition, laser-patterned interconnects demonstrate superior ruggedness and fatigue resistance under thermomechanical cycling and shock. This technology has been used to produce a ten-chip memory module, samples of which have been subjected to testing by means of relevant methods of MIL-STD 883C. >
Toll-like Receptor 7 Controls the Anti-Retroviral Germinal Center Response

The development of vaccines that can enhance immunity to viral pathogens is an important goal. However, the innate molecular pathways that regulate the strength and quality of the immune response remain largely uncharacterized. To define the role of Toll-like receptor (TLR) signaling in control of a model retroviral pathogen, Friend virus (FV), I generated mice in which the TLR signaling adapter Myd88 was selectively deleted in dendritic cell (DC) or in B cell lineages. Deletion of Myd88 in DCs had little effect on immune control of FV, while B cell specific deletion of Myd88 caused a dramatic increase in viral infectious centers and a significantly reduced antibody response, indicating that B cell-intrinsic TLR signaling plays a crucial role, while TLR signaling in DCs is less important. I then identified the single-stranded RNA sensing protein TLR7 as being required for antibody-mediated control of FV by analyzing mice deficient in TLR7. Remarkably, B cells in infected TLR7-deficient mice upregulated CD69 and CD86 early in infection, but failed to develop into germinal center B cells. CD4 T cell responses were also attenuated in the absence of TLR7, but CD8 responses were TLR7 independent, suggesting the existence of additional pathways for detection of retroviral particles. Together these results demonstrate that the vertebrate immune system detects retroviruses in vivo via TLR7 and that this pathway regulates a key checkpoint controlling development of germinal center B cells.
Multiple representation document development

The authors review a large number of document development systems for both text and graphics from the perspectives of source-language and direct-manipulation models. They describe the task domain and discuss the pros and cons of direct-manipulation techniques versus a programming-language source code and of a procedural versus declarative schemes. They then establish a framework for analyzing and designing multiple-representation systems. The central theme is that program constructs and visual feedback are complementary to each other and that a hybrid approach would be most desirable. >
Auto Correction Feedback for Ripple Suppression in a Chopper Amplifier

This paper proposes a local feedback, named Auto Correction Feedback (ACFB), for a chopper amplifier to suppress its offset related ripple. It nulls out the amplifier's initial offset in DC domain which would otherwise become modulated ripple at the chopper amplifier's output, instead of filtering the ripple with a post filter. The proposed ACFB has been implemented as a stand alone chopper operational amplifier fabricated in 0.64 mm2 die area with a 0.35 μm standard CMOS process. It achieves 10 μV maximum input offset voltage and 95 nV/rt(Hz) input voltage noise spectrum density flat down to 0.1 Hz, with a 1.8-5.5 V supply voltage range and 13 μA supply current dissipation. When configured in unity-gain, the typical magnitude of the input referred ripple at the chopping frequency is 9.4 μVrms, as a result of 45 dB ripple attenuation obtained by the ACFB. The analysis, the simulation, and the measurement prove there is no noise penalty due to the addition of ACFB.
Message-Passing Performance of Various Computers

This report compares the performance of different computer systems for basic message passing. Latency and bandwidth are measured on Convex, Cray, IBM, Intel, KSR, Meiko, nCUBE, NEC, SGI, and TMC multiprocessors. Communication performance is contrasted with the computational power of each system. The comparison includes both shared and distributed memory computers as well as networked workstation clusters.
Detection of sentinel predictor-class associations with XCS: a sensitivity analysis

Knowledge discovery in databases has traditionally focused on classification, prediction, or in the case of unsupervised discovery, clusters and class definitions. Equally important, however, is the discovery of individual predictors along a continuum of some metric that indicates their association with a particular class. This paper reports on the use of an XCS learning classifier system for this purpose. Conducted over a range of odds ratios for a fixed variable in synthetic data, it was found that XCS discovers rules that contain metric information about specific predictors and their relationship to a given class. In addition, EpiXCS performs qualitatively similarly to See5, and both methods are comparable to logistic regression.
V2O3-Polymer Composite Thermistors

V2O3 was incorporated into polymer matrices to produce composite materials with low room-temperature resistivities and sizable positive temperature coefficient (PTC) resistance effects. In addition, a negative temperature coefficient effect, associated with the semiconductor-to-metal phase transition in V2O3, was also observed. The resistivity vs temperature curve for these composites resembles a square well with three temperature regimes in which the composite behaves like a semiconductor, a metal, and an insulator. The intensity of the PTC effect for these composites was found to be as large as 10 orders of magnitude.
Atmospheric delivery of a microwave clock using an optical frequency comb

Atmospheric delivery of a microwave clock using an optical frequency comb is tested over 60 m. Phase noise measurement shows a picosecond-scale rms timing jitter under various weather conditions. A strong amplitude-phase correlation is observed.
Immersions of surfaces in almost-complex 4-manifolds

In this paper, we investigate the relation between double points and complex points of immersed surfaces in almost-complex 4-manifolds and show how estimates for the minimal genus of embedded surfaces lead to inequalities between the number of double points and the number of complex points of an immersion.
Asymmetric dark matter annihilation as a test of non-standard cosmologies

We show that the relic abundance of the minority component of asymmetric dark matter can be very sensitive to the expansion rate of the Universe and the temperature of transition between a non-standard pre-Big Bang Nucleosynthesis cosmological phase and the standard radiation dominated phase, if chemical decoupling happens before this transition. In particular, because the annihilation cross section of asymmetric dark matter is typically larger than that of symmetric dark matter in the standard cosmology, the decrease in relic density of the minority component in non-standard cosmologies with respect to the majority component may be compensated by the increase in annihilation cross section, so that the annihilation rate at present of asymmetric dark matter, contrary to general belief, could be larger than that of symmetric dark matter in the standard cosmology. Thus, if the annihilation cross section of the asymmetric dark matter candidate is known, the annihilation rate at present, if detectable, could be used to test the Universe before Big Bang Nucleosynthesis, an epoch from which we do not yet have any data.
Combined neck dissection and postoperative radiation therapy in the management of the high-risk neck: A matched-pair analysis

Abstract Purpose: The purpose of this study was to determine the efficacy of postoperative adjuvant radiation therapy with regard to reducing the rate of recurrence in the neck, cancer-related death, and death from any cause in patients with squamous cell carcinoma of the head and neck region metastatic to neck nodes. Methods: This was retrospective review of patients with pathologically confirmed nodal metastases who underwent neck dissection and postoperative adjuvant radiation therapy for squamous cell carcinoma of the head and neck region. Time to recurrence in the dissection are of the neck, any recurrence in the neck, cancer-related death, and death from any cause were estimated with the Kaplan-Meier method. A matched-pair analysis was performed utilizing a cohort of patients who underwent neck dissection without postoperative radiation therapy. The patients from the two cohorts were matched according to previously reported high-risk features for cancer recurrence and death. Cox hazards models for the matched pairs were used to evaluate the relative risk of subsequent recurrence in the dissected side of the neck, any neck recurrence, cancer-related death, and overall survival. Materials: The medical records and pathologic slides of 95 consecutive patients with pathologically confirmed nodal metastases from squamous cell carcinoma of the head and neck region who underwent neck dissection and postoperative adjuvant radiation therapy between January 1974 and December 1990 were reviewed. Previously published data from 284 patients with squamous cell carcinoma of the head and neck region treated with neck dissection alone between January 1970 and December 1980 were used for a matched-pair analysis. Results: The relative risks for recurrence in the dissected side of the neck, any neck recurrence (discussed neck or delayed undissected neck metastasis), cancer-related death, and the death from any cause for patient treated with operation alone relative to those treated with operation and postoperative radition were 5.82, 4.72, 2.21, and 1.67, respectively. Conclusion: This study provides evidence that postoperative adjuvant radiation therapy for the high-risk neck can reduced the rate of recurrence with a dissected neck, delayed metastasis within an undissected neck, cancer-related death, and death from any cause.
A comparison of twin boundary pinning in nearly fully stoichiometric and oxygen deficient YBa/sub 2/Cu/sub 3/O/sub 7- delta /

The angular dependence of the magnetoresistance was measured on the same single crystal of YBa/sub 2/Cu/sub 3/O/sub 7- delta / prepared initially with a superconducting transition temperature of 93 K and then annealed to obtain a transition temperature of 56.9 K. A second oxygen deficient sample was produced with a transition temperature of 57.0 K and nearly identical transport characteristics. Twin boundary pinning superimposed on flux flow behavior was observed in both the 56.9 K and 93.0 K states for magnetic field rotation in the ab plane. For magnetic field rotations off the c-axis, twin boundary pinning is observed only for the nearly stoichiometric state. The broadening of the resistive transition in magnetic field (H//c) is observed to occur over a much larger interval of reduced temperature in the deoxygenated state. The enhanced broadening of the resistive transition in magnetic field and absence of twin boundary pinning may indicate that the vortex system is two-dimensional, and, in general, defects are rendered ineffective in pinning due to the absence of three-dimensional collective elastic effects. >
Nominal Wage Rigidity in Village Labor Markets

This paper tests for downward nominal wage rigidity in markets for casual daily agricultural labor in a developing country context. I examine wage and employment responses to rainfall shocks—which shift labor demand—in 500 Indian districts from 1956-2008. First, there is asymmetric wage adjustment: nominal wages rise in response to positive shocks but do not fall during droughts. Second, after transitory positive shocks have dissipated, nominal wages do not return to previous levels—they remain high in future years. Third, inflation moderates these eects: when inflation is higher, real wages are more likely to fall during droughts and after transitory positive shocks. Fourth, wage distortions generate employment distortions, creating boom and bust cycles: employment is lower in the year after a transitory positive shock than if the positive shock had not occurred; landless laborers experience a 6% employment reduction. Fifth, consistent with the misallocation of labor across farms, households with smaller landholdings increase labor supply to their own farms when they are rationed out of the external labor market. These findings indicate that wage rigidity lowers employment levels and increases employment volatility—in a setting with few institutional constraints. Data from a new survey I conducted in two Indian states suggests that agricultural workers and employers: view nominal wage cuts as unfair; are considerably less likely to regard real wage cuts as unfair if they are achieved through inflation; and believe that nominal wage cuts cause eort reductions.
Another look at technical efficiency in American states, 1979–2000

A recently developed stochastic frontier production function methodology is used to estimate econometrically how technical efficiency, technological progress, and returns to scale contributed to US states’ economic growth in 1979–2000. Improved regional human capital data that are superior to the traditional “years of school” data are included. In support of the prior literature, overall technical inefficiency is found to be low but unlike earlier studies diverging over time with almost no shifting of the aggregate frontier. Efficiency is positively associated with relative historical wealth, human capital, relatively worse recession experience, greater market concentration, and a smaller informal economy.
Accelerated engineering design optimization using successive matrix inversion method

In a design optimization procedure, many repeated system analyses are conducted to evaluate certain performances of successively modified structural designs. To alleviate the high computational cost of structural reanalysis, an augmented preconditioner is introduced by using the successive matrix inversion (SMI) method. The SMI method, as an exact matrix solver, is successively applied to an iterative procedure to accelerate the solution convergence by improving the numerical condition of the reanalysis system. In this work, a new iterative technique, the binomial series iterative (BSI) method, is developed from the binomial series expansion by using the same concept as SMI. As a combined iterative (CI) method, SMI is incorporated in the procedure of BSI. The CI method, combined with SMI, shows sufficient efficiency and robustness through a stable iterative behaviour due to simple and straightforward computations in the iterative procedure. Published in 2005 by John Wiley & Sons, Ltd.
Bridged spiropentanes: Ring expansion

Abstract Diazomethane ring expansion of tricyclo[4.1.0.0 1,3 ]heptan-4-one provides a convenient route to three carbon-bridged spiropentanes. The relative rates of reaction and the migratory preferences of cyclopropyl vs methylene were examined for several cyclopropyl alkyl ketones, and were correlated with the results of HF/6-31G ∗ MO calculations.
The design of a multilevel survey of children, families, and communities: The Los Angeles Family and Neighborhood Survey

Abstract In this paper, we describe the development and implementation of the multilevel sample design for the Los Angeles Family and Neighborhood Survey, a study of children, adults, families, and neighborhoods in Los Angeles County. This survey was designed to support multilevel analyses on a number of topics, including child development, residential mobility, and welfare reform. We describe the design of the baseline wave, highlighting the analytical and statistical issues that shaped the study. We also present the results of an in-depth statistical investigation of the survey’s ability to support multilevel analyses that was carried out as part of the study design. The results of this study provide important guideposts for future studies of neighborhoods and their effects on adults and children.
Phoenix - The First Mars Scout Mission

As the first of the new Mars scouts missions, the Phoenix project was selected by NASA in August of 2003. Four years later, almost to the day, Phoenix was launched from Cape Canaveral Air Station and successfully injected into an interplanetary trajectory on its way to Mars. This paper highlight some of the key changes since the 2006 IEEE paper of the same name, as well as activities, challenges and problems encountered on the way to the launch pad. Phoenix "Follows the water" responding directly to the recently published data from Dr. William Boynton, PI (and Phoenix co-I) of the Mars Odyssey gamma ray spectrometer (GRS). GRS data indicate extremely large quantities of water ice (up to 50% by mass) within the upper 50 cm of the northern polar regolith. Phoenix will land within the north polar region at 68.2degN, 233.4degW identified by GRS to harbor near surface water ice and provide in-situ confirmation of this extraordinary find. Our mission will investigate water in all its phases, and will investigate the history of water as evidenced in the soil characteristics that will be carefully examined by the powerful suite of onboard instrumentation. Access to the critical subsurface region expected to contain this information is made possible by a third generation robotic arm capable of excavating the expected Martian regolith to a depth of 1m. Phoenix has four primary science objectives: 1) Determine the polar climate and weather, interaction with the surface, and composition of the lower atmosphere around 70deg N for at least 90 sols focusing on water, ice, dust, noble gases, and C02. Determine the atmospheric characteristics during descent through the atmosphere. 2) Characterize the geomorphology and active processes shaping the northern plains and the physical properties of the near surface regolith focusing on the role of water. 3) Determine the aqueous mineralogy and chemistry as well as the adsorbed gases and organic content of the regolith. Verify the Odyssey discovery of near-surface ice. 4) Characterize the history of water, ice, and the polarclimate. Determine the past and present biological potential of the surface and subsurface environments.
Experiments on Control of Limit-Cycle Oscillations in a Typical Section

The experimental application of active control to reduce or eliminate limit-cycle oscillations in a typical section airfoil is presented. The test rig consists of a three-degree-of-freedom typical section which has free play in the e ap restoring stiffness. Such a free play was intended to mimic that associated with control surface mechanism backlashinarealsystem.Controliseffectedby meansofanactuatoractingonthee ap.AlinearquadraticGaussian optimization scheme is used to design a compensator that will accomplish three goals: 1 ) reduce or eliminate limitcycle oscillations, 2 ) increase the e utter boundary, and 3 ) be robust to variations in the e ow velocity. Although the typical section isa nonlineardynamicsystem, thecontrol system design wasbased on thelineartypical section with no freeplay. The results presented indicatethat each ofthesegoalswas accomplished. More specie cally, limit-cycle oscillations were eliminated, the e utter velocity was increased by 17%, and the control system was stable over a wide range of e ow conditions.
Characterization of aquifer heterogeneity using transient hydraulic tomography

[1] Hydraulic tomography is a cost-effective technique for characterizing the heterogeneity of hydraulic parameters in the subsurface. During hydraulic tomography surveys a large number of hydraulic heads (i.e., aquifer responses) are collected from a series of pumping or injection tests in an aquifer. These responses are then used to interpret the spatial distribution of hydraulic parameters of the aquifer using inverse modeling. In this study, we developed an efficient sequential successive linear estimator (SSLE) for interpreting data from transient hydraulic tomography to estimate three-dimensional hydraulic conductivity and specific storage fields of aquifers. We first explored this estimator for transient hydraulic tomography in a hypothetical one-dimensional aquifer. Results show that during a pumping test, transient heads are highly correlated with specific storage at early time but with hydraulic conductivity at late time. Therefore reliable estimates of both hydraulic conductivity and specific storage must exploit the head data at both early and late times. Our study also shows that the transient heads are highly correlated over time, implying only infrequent head measurements are needed during the estimation. Applying this sampling strategy to a well-posed problem, we show that our SSLE can produce accurate estimates of both hydraulic conductivity and specific storage fields. The benefit of hydraulic tomography for ill-posed problems is then demonstrated. Finally, to affirm the robustness of our SSLE approach, we apply the SSLE approach to a hypothetical three-dimensional heterogeneous aquifer.
Robust flight schedules through slack re-allocation

A myriad of uncontrollable factors in airline operations makes delays and disruptions unavoidable. To limit complexity, most conventional scheduling models, however, ignore the occurrence of unplanned events during operations. This leads to schedules that are vulnerable to delays and disruptions. In this work, we propose a flight schedule adjustment model that strategically re-allocates existing schedule slack to achieve a more robust schedule. Using data from an international carrier, we evaluate the resulting schedules using various performance metrics, including delay propagation and passenger delays. The results show that minor schedule adjustments to the original schedule can significantly improve overall schedule performance. In addition to the modeling contribution, we provide managerial insights obtained through extensive computational experiments. Unlike earlier works on slack re-allocation that focus primarily on demonstrating the effectiveness of the methods, our paper is, to our knowledge, the first one that also addresses a fundamental question pertaining to how airline characteristics and operations influence the strategy for robust scheduling.
Properties and Structure of Lead Fluorosilicate Glasses

An extensive glass-forming region has been determined for the lead fluorosilicate system. These glasses have a very high anionic (fluorine) conductivity. The value of 2 x 10-4ω-1.cm-1 at slightly less than 200°C found for one glass is the highest anionic conductivity reported to date in a glass. Glass transition temperatures, thermal expansion coefficients, and UV-visible spectra were also measured. Results of these measurements and melt-history studies will be discussed and related to a proposed structural model for the lead fluorosilicate glasses.
Fiscal Policy Instruments for Reducing Congestion and Atmospheric Emissions in the Transport Sector : A Review

This paper reviews the literature on the fiscal policy instruments commonly used to reduce transport sector externalities. The findings show that congestion charges would reduce vehicle traffic by 9 to 12 percent and significantly improve environmental quality. The vehicle tax literature suggests that every 1 percent increase in vehicle taxes would reduce vehicle miles by 0.22 to 0.45 percent and CO2 emissions by 0.19 percent. The fuel tax is the most common fiscal policy instrument; however its primary objective is to raise government revenues rather than to reduce emissions and traffic congestion. Although subsidizing public transportation is a common practice, reducing emissions has not been the primary objective of such subsidies. Nevertheless, it is shown that transport sector emissions would be higher in the absence of both public transportation subsidies and fuel taxation. Subsidies are also the main policy tool for the promotion of clean fuels and vehicles. Although some studies are very critical of biofuel subsidies, the literature is mostly supportive of clean vehicle subsidies.
SEQUENTIAL AUCTIONS WITH RANDOMLY ARRIVING BUYERS

We analyze a dynamic market in which buyers compete in a sequence of private-value auctions for differentiated goods. New buyers and new objects may arrive at random times. Since objects are imperfect substitutes, buyers' values are not persistent. Instead, each buyer's private value for a new object is a new independent draw from the same In this paper, we consider a model of dynamic markets in which buyers and sellers arrive randomly to the market and examine the equilibrium behavior of market participants in response to these arrivals. In particular, we investigate the role of current and anticipated future market conditions in determining endogenous outside options in this setting. We characterize the influence of these outside options on equilibrium price determination, and study the manner in which equilibrium payoffs and behavior are affected by both current conditions and future dynamics. In our model, buyers face an infinite sequence of auctions for heterogeneous but stochastically equivalent objects—each buyer's private value for a new object is a new independent draw from a fixed distribution—that arrive at random times. Moreover, new buyers probabilistically arrive on the market in each period. Thus, in any given auction, buyers are presented with the outside option of participating in a future auction for an imperfectly substituted "equivalent" object, but with a potentially different number of competitors. We describe the unique symmetric Markov equilibrium of this model by deriving a precise characterization of this option value.
Holography, diffeomorphisms, and scaling violations in the CMB

We analyze diffeomorphism invariance in inflationary spacetimes regulated by a boundary at late time. We present the action for quadratic fluctuations in the presence of a boundary, and verify that it is gauge invariant precisely when the correct local counterterms are included. The scaling behavior of bulk correlation functions at the boundary is determined by Callan-Symanzik equations which predict scaling violations in agreement with the standard inflationary predictions for spectral indices of the CMB.
The KK-monopole/NS5-brane in doubled geometry

The Kaluza-Klein monopole has been recognized as a string background with significant non-geometric features: it must appear “localized” to winding strings to match the NS5-brane’s localization on the T-dual circle. In this work, we explicitly construct this T-dual system in the doubled geometry formalism, which proves to successfully describe the duality despite a broken isometry on one side of the duality pair. We further suggest an extension of the doubled formalism to the gauged linear sigma models describing this system (both bosonic and supersymmetric) and show that previous calculations of world sheet instanton effects are best understood in this doubled form.
ESTIMATES OF THE PLANET YIELD FROM GROUND-BASED HIGH-CONTRAST IMAGING OBSERVATIONS AS A FUNCTION OF STELLAR MASS

We use Monte Carlo simulations to estimate the number of extrasolar planets that are directly detectable in the solar neighborhood using current and forthcoming high-contrast imaging instruments. Our calculations take into consideration the important factors that govern the likelihood for imaging a planet, including the statistical properties of stars in the solar neighborhood, correlations between star and planet properties, observational effects, and selection criteria. We consider several different ground-based surveys, both biased and unbiased, and express the resulting planet yields as a function of stellar mass. Selecting targets based on their youth and visual brightness, we find that strong correlations between star mass and planet properties are required to reproduce high-contrast imaging results to date (i.e., HR 8799, β Pic). Using the most recent empirical findings for the occurrence rate of gas-giant planets from radial velocity (RV) surveys, our simulations indicate that naive extrapolation of the Doppler planet population to semimajor axes accessible to high-contrast instruments provides an excellent agreement between simulations and observations using present-day contrast levels. In addition to being intrinsically young and sufficiently bright to serve as their own beacon for adaptive optics correction, A-stars have a high planet occurrence rate and propensity to form massive planets in wide orbits, making them ideal targets. The same effects responsible for creating a multitude of detectable planets around massive stars conspire to reduce the number orbiting low-mass stars. However, in the case of a young stellar cluster, where targets are approximately the same age and situated at roughly the same distance, MK-stars can easily dominate the number of detections because of an observational bias related to small number statistics. The degree to which low-mass stars produce the most planet detections in this special case depends upon whether multiple formation mechanisms are at work. Upon relaxing our assumption that planets in ultra-wide (a > 100 AU) orbits resemble the RV sample, our simulations suggest that the companions found orbiting late-type stars (AB Pic, 1RXSJ1609, GSC 06214, etc.) are consistent with a formation channel distinct from that of RV planets. These calculations explain why planets have thus far been imaged preferentially around A-stars and K-, M-stars, but no spectral types in between, despite concerted efforts targeting F-, G-stars.