cssi/SciSciGPT-SciSciNet huggingface dataset:
PUBLIC-PRIVATE SECTOR WAGE DIFFERENTIALS AND RETURNS TO EDUCATION IN DJIBOUTI

Do public sector workers earn a wage premium in Djibouti and are the returns to education different across the sectors? The authors estimate private and public sector wage earnings using 1996 household survey data, while controlling for selectivity using Heckman's two stage approach. They find that Djiboutian public sector employees earn a wage premium, independent of their personal attributes and human capital endowments, and are more likely to be males and have parents in the public sector. Workers in the public sector earn higher private rates of return to education than do private sector workers with post-secondary schooling. These results raise concerns about current government hiring and wage-setting practices that generate distortions in the labor market and are not efficiently allocating labor and public resources.
Molecular characterization of human rhinovirus field strains isolated during surveillance of enteroviruses

Human rhinoviruses (HRVs), which are the most frequent causative agents of acute upper respiratory tract infections, are abundant worldwide. We have identified HRV strains in environmental specimens collected in Finland, Latvia and Slovakia during the surveillance of polio- and other enteroviruses. These acid-sensitive HRV strains were isolated under conditions optimized for growth of most of the enteroviruses, i.e. in stationary human rhabdomyosarcoma cells incubated at 36 degrees C. Phylogenetic analysis of the sequences derived from the partial 5' non-coding region and the capsid region coding for proteins VP4/VP2 and VP1 showed that the HRV field strains clustered together with prototype strains of the HRV minor receptor group. Partial sequences of the 3D polymerase coding region generally followed this pattern, with the exception of a set of three HRV field strains that formed a subcluster not close to any of the established HRV-A types, suggesting that recombination may have occurred during evolution of these HRV strains. Phylogenetic analysis of the VP4/VP2 capsid protein coding region showed that the 'environmental' HRV field strains were practically identical to HRV strains recently sequenced by others in Australia, the United States and Japan. Analysis of amino acids corresponding to the intercellular adhesion molecule-1 receptor footprint in major receptor group HRVs and also in the low-density lipoprotein receptor footprint of minor receptor group HRVs showed conservation of the 'minor receptor group-like' amino acids, indicating that the field strains may have maintained their minor receptor group specificity.
ECONOMIC DEVELOPMENT AS SELF-DISCOVERY

In the presence of uncertainty about what a country can be good at producing, there can be great social value to discovering costs of domestic activities because such discoveries can be easily imitated. We develop a general-equilibrium framework for a small open economy to clarify the analytical and normative issues. We highlight two failures of the laissez-faire outcome: there is too little investment and entrepreneurship ex ante, and too much production diversification ex post. Optimal policy consists of counteracting these distortions: to encourage investments in the modern sector ex ante, but to rationalize production ex post. We provide some informal evidence on the building blocks of our model.
20 GHz power combining slot-oscillator array

A four element power combining array of quasi-optical slot oscillators has been constructed. The array delivers a total power output of 68 mW with as effective isotropic radiated power of 4.4 W. The DC to RF efficiency of the array is 12%. The arrangement of the array can be infinitely extended in two dimensions to increase the total output power. >
Race affects insulin and GLP-1 secretion and response to a long-acting somatostatin analogue in obese adults

OBJECTIVE: This study investigated (1) the effect of octreotide-LAR (Sandostatin-LAR®Depot; Novartis) on the enteroinsular axis in a biracial cohort of severely obese adults, (2) whether octreotide suppression of insulin secretion occurs by both a direct β-cell effect and through mediating a glucagon-like peptide 1 (GLP-1) response, and (3) whether differences in GLP-1 concentrations could explain racial differences in insulin concentrations. DESIGN: Prospective, open-label trial using a pre–post test design. SETTING: Single university, clinical research center. SUBJECTS: In all, 42 healthy, severely obese Caucasian and African-American (AA) adults (93% female, 64% Caucasian, age=37.8±1.2 y, weight=123±4.2 kg, BMI=44.5±1 kg/m2), recruited through physician referral and newspaper ads, participated in the study. INTERVENTIONS: Indices of β-cell activity, insulin and GLP-1 response before and during a 75-gm oral glucose tolerance test were determined before and after 24 weeks of octreotide-LAR. RESULTS: AA exhibited higher β-cell activity, and insulin and GLP-1 concentrations than Caucasians. Octreotide-LAR suppressed the insulin and GLP-1 levels in both groups.
Structural and Electronic Properties of Neutral and Ionic GanOn Clusters with n = 4−7

The structural and electronic properties of the (Ga2O3)n clusters (n = 1–10) have been studied within the framework of density functional theory. The (Ga2O3)n clusters show the preference for 4-membered (Ga2O2) and 6-membered (Ga3O3) rings. For n = 4, the lowest energy configuration appears to be derived from the bulk corundum (α-Ga2O3) configuration. For larger clusters (n = 5–10), the structures evolve around the corundum fragment and are more symmetric with layered configuration. There are 3-, 4-, and 5-fold coordinated Ga atoms and 2-, 3-, and 4-fold coordinated oxygen atoms. The (Ga2O3)n structures have similarity to that of the α-Ga2O3 phase, and the average coordination of Ga and oxygen atoms in clusters are lower than the values in the α-Ga2O3. The ionization-induced distortions in the lowest-energy configuration of the respective neutral clusters are small. The isomers with cage configurations lie higher in energy compared with the layered lowest energy structures we have obtained. A sequential a...
Robust watermarking using robust coefficients

Watermarking of digital property has received a significant amount of attention in recent years. Robust watermarking of digital images and video for the purpose of copyright protection is a particularly important and challenging topic. In this paper, we provide a technique to improve the robustness of algorithms that require selection of transform coefficients for watermarking. Experimental results show that by strategically choosing the best locations for watermark embedding, the overall robustness of the watermarking algorithm can be improved.
Power-Controlled Feedback and Training for Two-Way MIMO Channels

Most communication systems use some form of feedback, often related to channel state information. The common models used in analyses either assume perfect channel state information at the receiver and/or noiseless state feedback links. However, in practical systems, neither is the channel estimate known perfectly at the receiver and nor is the feedback link perfect. In this paper, we study the achievable diversity multiplexing tradeoff using i.i.d. Gaussian codebooks, considering the errors in training the receiver and the errors in the feedback link for frequency division duplex (FDD) systems, where the forward and the feedback are independent multiple input multiple output (MIMO) channels. Our key result is that the maximum diversity order with one-bit of feedback information is identical to systems with more feedback bits. Thus, asymptotically in SNR, more than one bit of feedback does not improve the system performance at constant rates. Furthermore, the one-bit diversity-multiplexing performance is identical to the system which has perfect channel state information at the receiver along with noiseless feedback link. This achievability uses novel concepts of power controlled feedback and training, which naturally surface when we consider imperfect channel estimation and noisy feedback links. In the process of evaluating the proposed training and feedback protocols, we find an asymptotic expression for the joint probability of the SNR exponents of eigenvalues of the actual channel and the estimated channel which may be of independent interest.
Effect of Velocity and Temperature Distribution at the Hole Exit on Film Cooling of Turbine Blades

An existing three-dimensional Navier-Stokes code (Arnone et al, 1991), modified Turbine Branch, to include film cooling considerations (Garg and Gaugler, 1994), has been used to study the effect of coolant velocity and temperature distribution at the hole exit on the heat transfer coefficient on three film-cooled turbine blades, namely, the C3X vane, the VKI rotor, and the ACE rotor. Results are also compared with the experimental data for all the blades. Moreover, Mayle's transition criterion (1991), Forest's model for augmentation of leading edge heat transfer due to free-stream turbulence (1977), and Crawford's model for augmentation of eddy viscosity due to film cooling (Crawford et al, 1980) are used. Use of Mayle's and Forest's models is relevant only for the ACE rotor due to the absence of showerhead cooling on this rotor. It is found that, in some cases, the effect of distribution of coolant velocity and temperature at the hole exit can be as much as 60 percent on the heat transfer coefficient at the blade suction surface, and 50 percent at the pressure surface. Also, different effects are observed on the pressure and suction surface depending upon the blade as well as upon the hole shape, conical or cylindrical.
A Finitary Version of Gromov’s Polynomial Growth Theorem

We show that for some absolute (explicit) constant C, the following holds for every finitely generated group G, and all d> 0: If there is some R0 > exp(exp(Cd C )) for which the number of elements in a ball of radius R0 in a Cayley graph of G is bounded by R d ,t henG has a finite-index subgroup which is nilpotent (of step <C d ). An effective bound on the finite index is provided if "nilpotent" is replaced by "polycyclic", thus yielding a non-trivial result for finite groups as well.
Stereoselective sonochemical reductive silylation of geminal dibromocyclopropanes by bulk magnesium

Abstract Ultrasonic irradiation of a THF solution containing both trimethysilyl chloride and a bicyclic 1,1-dibromocyclopropane in the presence of bulk magnesium affords 1-trimethylsilyl-1-bromocyclopropanes in 72–93% yield. The sonochemical reactions proceed stereoselectively to afford as the major product the product in which the trimethylsilyl group is cis to the hydrogen atoms at the ring juncture.
Organocatalytic C–H hydroxylation with Oxone® enabled by an aqueous fluoroalcohol solvent system

Selective hydroxylation of 3° and benzylic C–H bonds is made possible using a non-metal-based catalyst system, Oxone as the terminal oxidant, and an aqueous fluoroalcohol solvent mixture. The choice of solvent is uniquely effective for this process, but seemingly at odds with our finding that H2O promotes reduction of the oxaziridine intermediate. Our studies suggest that the hydroxylation reaction is occurring within a fluoroalcohol microdroplet, which both concentrates the reactants and mitigates the deleterious impact of H2O on oxaziridine stability. These discoveries have led to demonstrable improvements in the organocatalytic oxygenation of hydrocarbon substrates and, for the first time, the successful use of Oxone with this catalyst system. Reactions generally afford product and unreacted starting material in near quantitative amounts and display outstanding selectivity for 3° and benzylic C–H bond oxidation.
Stroke Therapy through Motion-Based Games: A Case Study

In the United States alone, more than five million people are living with long term motor impairments caused by a stroke. Recently, video games with affordable motion-based input devices have been proposed as a part of therapy to help people recover lost range of motion and motor control. While researchers have demonstrated the potential utility of therapeutic games through controlled studies, relatively little work has explored their long-term home-based use. We conducted a six-week home study with a 62-year-old woman who was seventeen years post-stroke. She played therapeutic games for approximately one hour a day, five days a week. Over the six weeks, she recovered significant motor abilities, which is unexpected given the time since her stroke. We explore detecting such improvements early, using game logs for daily measurements of motor ability to complement the standard measurements that are taken less often. Through observations and interviews, we present lessons learned about the barriers and opportunities that arise from long-term home-based use of therapeutic games.
Implications and Applications of Kinematic Galaxy Scaling Relations

Galaxy scaling relations, which describe a connection between ostensibly unrelated physical characteristics, testify to an underlying order in galaxy formation that requires understanding. I review the development of a scaling relation that (1) unites the well-known fundamental plane (FP) relation of giant elliptical galaxies and Tully-Fisher (TF) relation of disk galaxies, (2) fits low mass spheroidal galaxies, including the ultrafaint satellites of our galaxy, (3) explains the apparent shift of lenticular galaxies relative to both FP or TF, (4) describes all stellar dynamical systems, including systems with no dark matter (stellar clusters), (5) associates explicitly the numerical coefficients that account for the apparent tilt of the FP away from the expectation drawn from the virial theorem with variations in the total mass-to-light ratio of galaxies within the half-light radius, (6) connects with results that demonstrate the robustness of mass estimators when applied at the half-light radius, and (7) results in smaller scatter for disk galaxies than the TF relation. I review two applications: (1) the cross-calibration of distance measurement methods and (2) the determination of mass-to-light ratios of simple stellar populations and implications for the stellar initial mass function.
PRICE STRATEGY OLIGOPOLY WITH PRODUCT VARIATION

Abstract : This paper mathematically formulates an example of firms in monopolistic competition and investigate noncooperative behavior as the number of firms increases and as the level of product variation is decreased.
DYNAMIC COLLECTIVE CHOICE WITH ENDOGENOUS STATUS QUO

We analyze a bargaining situation in which preferences evolve over time and the previous agreement becomes the next status quo. The endogeneity of the status quo exacerbates the players’ conflict of interest: Players disagree more often than under exogenous status quo. This leads to inefficiencies and status quo inertia. Under certain conditions, the negotiations can come to a complete gridlock: Players never reach an agreement. Gridlock can occur between players with arbitrarily similar preferences, provided they are sufficiently patient. In legislative settings, our model predicts polarization and explains why legislators may fail to react promptly to economic shocks.
Microscopic approaches to nuclear structure: Configuration interaction

The configuration interaction (CI) approach to solving the nuclear many-body problem, also known as the interacting shell model, has proven to be powerful tool in understanding the structure of nuclei. The principal criticism of past applications of the shell model is the reliance on empirical tuning to interaction matrix elements. If an accurate description of nuclei far from the valley of stability, where little or no data is available, a more fundamental approach is needed. This starts with recent ab initio approaches with effective interactions in the no-core shell model (NCSM). Using effective-field theory for guidance, fully ab initio descriptions of nuclei up to 16O with QCD based NN, NNN, and NNNN interactions will be possible within the next five years. An important task is then to determine how to use these NCSM results to develop effective interactions to describe heavier nuclei without the need to resort to an empirical retuning with every model space. Thus, it is likely that more traditional CI applications utilizing direct diagonalization and more fundamental interactions will be applicable to nuclei with perhaps up to one hundred constituents. But, these direct diagonalization CI applications will always be computationally limited due to the rapid increase in the number of configurations with particle number. Very recently, the shifted-contour method has been applied to the Auxiliary-field Monte Carlo approach to the Shell Model (AFMCSM), and preliminary applications exhibit a remarkable taming of the notorious sign problem. If the mitigation of the sign problem holds true, the AFMCSM will offer a method to compute quantum correlations to mean-field applications for just about all nuclei; giving exact results for CI model spaces that can approach 1020-25. In these lectures, I will discuss modern applications of CI to the nuclear many-body problem that have the potential to guide nuclear structure theory into the next decade.
Study of the long term stability of the effective concentration of ionized space charges (N/sub eff/) of neutron irradiated silicon detectors fabricated by various thermal oxidation processes

Experimental study of the reverse annealing of the effective concentration of ionized space charges (N/sub eff/, also called effective doping or impurity concentration) of neutron irradiated high resistivity silicon detectors fabricated on wafers with various thermal oxides has been conducted at room temperature (RT) and elevated temperature (ET). Various thermal oxidations with temperatures ranging from 975/spl deg/C to 1200/spl deg/C with and without trichlorethane (TCA), which result in different concentrations of oxygen and carbon impurities, have been used. It has been found that, the RT annealing of the N/sub eff/ is hindered initially (t 42 days after irradiation) N/sub eff/ reverse annealing. No apparent effect of oxygen on the stability of N/sub eff/ has been observed at RT. At elevated temperature (80/spl deg/C), no significant difference in annealing behavior has been found for detectors fabricated on silicon wafers with various thermal oxides. It is apparent that for the initial stages (first and/or second) of N/sub eff/ reverse annealing, there may be no dependence on the oxygen and carbon concentrations in the ranges studied. >
A framework for orbital performance evaluation in Distributed Space Missions for earth observation

Distributed Space Missions (DSMs) are gaining momentum in their application to earth science missions owing to their unique ability to increase observation sampling in angular, spatial, spectral and temporal dimensions simultaneously. DSM architectures have a large number of design variables and since they are expected to increase mission flexibility, scalability, evolvability and robustness, their design is a complex problem with many variables and objectives affecting performance. There are few open-access tools available to explore the tradespace of variables which allow performance assessment and are easy to plug into science goals, and therefore select the most optimal design. This paper presents a software framework developed on the MATLAB engine interfacing with STK, for DSM orbit design and selection. The associated tool is capable of generating thousands of homogeneous constellation or formation flight architectures based on pre-defined design variable ranges and sizing those architectures in terms of pre-defined performance metrics. The metrics can be input into observing system simulation experiments, as available from the science teams, allowing dynamic coupling of science and engineering designs. Design variables include constellation type, formation flight type, instrument view, altitude and inclination of chief orbits, differential orbital elements, leader satellites, latitudes or regions of interest, planes and satellite numbers. Intermediate performance metrics include angular coverage, number of accesses, revisit coverage, access deterioration over time at every point of the Earth's grid. The orbit design process can be streamlined and variables more bounded along the way, owing to the availability of low fidelity and low complexity models such as corrected HCW equations up to high precision STK models with J2 and drag. The tool can thus help any scientist or program manager select pre-Phase A, Pareto optimal DSM designs for a variety of science goals without having to delve into the details of the engineering design process. This paper uses cases measurements for multi-angular earth observation to demonstrate the applicability of the tool.
Effective Preparation for Graduate Language Requirements

IN THE last twenty-five years a new situation has been developing in the technological schools of this country. Foreign language study in high school has diminished and the advisors in many schools now suggest, to students who seem to have a bent for science or engineering, that other subjects will be more valuable to them in college than language. To be sure, n the few schools where German is taught, this is still recommended for physics and chemistry majors. The result of this trend is that an increasing fraction of our college students have no background of experience in language study. For the average college undergraduate in the engineering courses there probably is no point at which he feels the need of a foreign language. In his reading he may find references to articles in German or French or even Russian, but he can do satisfactory work in his required subjects without consulting any foreign sources in the original language. The science courses at M.I.T. such as chemistry, physics, mathematics and biology require students to take a year of French if they have had German, those who have had no German before entering to take one year of that. Chemical Engineering stands out as the exception among the engineering courses in that it requires of its students one semester of language, either German, or if they have had German, Russian. Many of these students resent being forced by fiat to study foreign languages and they are quite likely to place them on a low level in the order of their preoccupations, spending their major effort in the preparation of what they consider more practical subjects, since they discern no clear relationship between their language courses and their professional training. The attitude of the average undergraduate toward foreign language study is similar to his attitude toward the study of English, history and other humanities. I have said average; perhaps I should have said below average, for most gratifying exceptions immediately come to mind, men and women who approach the humanities with enthusiasm, enjoying the opening up of new avenues of thought and experience, entirely apart from their professional aims.
Overreaction, Delayed Reaction, and Contrarian Profits

This article examines the contribution of stock price overreaction and delayed reaction to the profitability of contrarian strategies. The evidence indicates that stock prices overreact to firm-specific information, but react with a delay to common factors. Delayed reactions to common factors give rise to a size-related lead-lag effect in stock returns. In sharp contrast with the conclusions in the extant literature, however, this article finds that most of the contrarian profit is due to stock price overreaction and a very small fraction of the profit can be attributed to the lead-lag effect
Cone-Guided Fast Ignition with no Imposed Magnetic Fields

Simulations are presented of ignition-scale fast ignition targets with the integrated Zuma-Hydra PIC-hydrodynamic capability. We consider a spherical DT fuel assembly with a carbon cone, and an artificially-collimated fast electron source. We study the role of E and B fields and the fast electron energy spectrum. For mono-energetic 1.5MeV fast electrons, without E and B fields, ignition can be achieved with fast electron energy E ig f = 30kJ. This is 3.5× the minimal deposited ignition energy of 8.7kJ for our fuel density of 450g/cm 3 . Including E and B fields with the resistive Ohm's law E = Jb gives E ig = 20kJ, while using the full Ohm's law gives E ig f > 40kJ. This is due to magnetic self-guiding in the former case, and ∇n ×∇ T magnetic fields in the latter. Using a realistic, quasi two-temperature energy spectrum derived from PIC laser-plasma simulations increases E ig f to (102, 81, 162) kJ for (no E/B, E = Jb, full Ohm's law). Such electrons are too energetic to stop in the optimal hot spot depth.
Ruthenium-Catalyzed Vinylsilane Synthesis and Cross-Coupling as a Selective Approach to Alkenes: Benzyldimethylsilyl as a Robust Vinylmetal Functionality

Ruthenium-catalyzed alkyne hydrosilylation or silyl-alkyne Alder ene reactions provide entry into benzyldimethylsilyl (BDMS)-substituted alkenes. The BDMS-vinylsilanes are further elaborated through mild palladium-catalyzed cross coupling and show significant stability to intervening synthetic operations, including silyl ether deprotection.
Assertion-Based Design Exploration of DVS in Network Processor Architectures

With the scaling of technology and higher requirements on performance and functionality, power dissipation is becoming one of the major design considerations in the development of network processors. In this paper, we use an assertion-based methodology for system-level power/performance analysis to study two dynamic voltage scaling (DVS) techniques, traffic-based DVS and execution-based DVS, in a network processor model. Using the automatically generated distribution analyzers, we analyze the power and performance distributions and study their trade-offs for the two DVS policies with different parameter settings such as threshold values and window sizes. We discuss the optimal configurations of the two DVS policies under different design requirements. By a set of experiments, we show that the assertion-based trace analysis methodology is an efficient tool that can help a designer easily compare and study optimal architectural configurations in a large design space.
Brand-specific tastes for quality

This paper develops a model of nonlinear pricing with competition. The novel ele- ment is that each consumer's willingness to pay for quality is private information and is allowed to dier across brands. The consumer's preferences are represented by a multidimensional type containing the marginal value of quality for dierent products. Buyers with high willingness to pay for quality also display strong preferences for par- ticular brands, and require higher discounts in order to switch away from their favorite product. Therefore, competition is …ercer for buyers with lower tastes for quality, and hence more elastic demands. This is in sharp contrast to earlier models in which com- petition is …ercer for higher-taste, more valuable buyers. In equilibrium, …rms either compete intensively for the entire market (providing strictly positive rents to all con- sumers) or shut down the least pro…table segment of the market. Quality levels are distorted downwards for all buyers, except for those with the highest type. The number of competing …rms and the degree of correlation across brand preferences enhance the e¢ ciency of the allocation.
Tune measurement in the NSLS booster synchrotron

The NSLS booster synchrotron can accelerate an electron beam from approximately 80 to 750 MeV in 0.7 sec. The betatron tunes can change during acceleration by as much as 0.1 units, causing beam loss as they cross resonance lines. Precise measurements with a conventional swept spectrum analyzer have always been difficult because of the rapid variation of tune as the magnets are ramped. We are now using a system based on a Tektronix 3052 digital spectrum analyzer that can obtain a complete frequency spectrum over a 10 MHz bandwidth in 200 /spl mu/sec. Betatron oscillations are stimulated for the measurements by applying white noise to the beam through stripline electrodes. We will describe the instrumentation, our measurements of tune as a function of time during the acceleration cycle, and the resulting improvements to the booster operation. >
Sequenced reactions with samarium(II) iodide. Intermolecular ketyl-olefin coupling/intramolecular nucleophilic acyl substitution for the preparation of six-, seven-, and eight-membered carbocycles

Abstract A samarium(II) iodide-promoted sequence consisting of an intermolecular ketyl-olefin coupling followed by an intramolecular nucleophilic acyl substitution is described. This process leads to functionalized six- to eight-membered monocyclic and bicyclic ring systems in moderate to good yields.
The minimum Jeans mass, brown dwarf companion IMF, and predictions for detection of Y-type dwarfs

Cool L- and T-type objects were discovered first as companions to stars in 1988 and 1995, respectively. A certain example of the even cooler Y-type spectral class ( 500 K) has not been seen. Recent infrared-imaging observations of stars and brown dwarfs indicate that substellar companions with large semi-major axes and with masses less than the brown dwarf/giant planet dividing line (~13.5) are rare. Theoretical considerations of the Jeans mass fragmentation of molecular clouds are consistent with this minimum mass cutoff and also with the semi-major axis (hundreds of AU) characteristic of the lowest mass imaged companions. As a consequence, Y-class companions with large semi-major axes should be scarce around stars 0.2 power.
Uncertainty, Time-Varying Fear, and Asset Prices

I construct an equilibrium model that captures salient properties of index option prices, equity returns, variance, and the risk-free rate. A representative investor makes consumption and portfolio choice decisions that are robust to his uncertainty about the true economic model. He pays a large premium for index options because they hedge important model misspecification concerns, particularly concerning jump shocks to cash flow growth and volatility. A calibration shows that empirically consistent fundamentals and reasonable model uncertainty explain option prices and the variance premium. Time variation in uncertainty generates variance premium fluctuations, helping explain their power to predict stock returns.
SKILL BIAS MAGNIFIED: INTERSECTORAL LINKAGES AND WHITE-COLLAR LABOR DEMAND IN U.S. MANUFACTURING

Abstract This paper presents a novel stylized fact and analyzes its contribution to the skill bias of technical change in U.S. manufacturing. The share of skilled labor embedded in intermediate inputs correlates strongly with the skill share employed in final production. This finding points toward an intersectoral technology-skill complementarity (ITSC). Together with input-output linkages, the observed complementarity delivers a multiplier that reinforces skill demand along the production chain. Reduced-form estimates suggest that the effect is quantitatively important, explaining about as much skill upgrading as outsourcing. Empirical evidence suggests that one channel through which this complementarity works is product innovation. I also analyze the importance of different drivers of skill upgrading over time. While foreign outsourcing and IT capital are associated with skill demand particularly strongly from the 1980s on (a period of rapidly increasing skill premiums), R&D contributed stably throughou...
Vinylalumination for the Synthesis of Functionalized Allyl Alcohols, Vinylepoxides, and α-Alkylidene-β-hydroxy-γ-lactones

A modified hydroalumination protocol for the preparation of [α-(ethoxycarbonyl)vinyl]diisobutylaluminum and its β-methyl or -phenyl analogues was developed. These vinylaluminum reagents react with aldehydes and ketones to provide the corresponding functionalized allyl alcohols in good to excellent yields. Perfluoroalkyl and -aryl carbonyl compounds, α-keto esters, α-acyl cyanides, and α-acetylenic ketones provide the corresponding α-hydroxyalkenes in high yields. The allyl alcohol product ratios from the vinylalumination of unsymmetrical α-diketones with [α-(ethoxycarbonyl)vinyl]diisobutylaluminum and its β-methyl or -phenyl analogues depend on the steric and electronic environments of the ketones as well as the reagents. The products from the vinylalumination of α-bromoaldehydes and -ketones were cyclized with K2CO3 or KF under nonaqueous conditions to provide functionalized vinylepoxides in high yields. Vinylaluminations of keto-protected pyruvaldehyde provided the products, which were converted to α-al...
Impact of Streamflow Persistence on Hydrologic Design

Conventional methods for estimating the average return period, E(T), and failure risk, R, generally ignore the impact of persistence in annual streamflows on associated probabilistic statements and streamflow statistics. Recent evaluations of streamflow observations indicate statistically significant serial correlations ~persistence! associated with annual low flows in the United States. We define the average occurrence interval E(T) as the expected time to the first event, and we present a method for estimating E(T) and R in the presence of persistence. We show that for observed ranges of persistence, E(T) can be nearly 100% greater and R more than 20% lower than conventional estimates. This implies that the expected design life of a system is longer when persistence is taken into account. Also, by ignoring persistence, low flow quantiles may be underestimated by 50% or more. An evaluation of the effect of persistence on drought risk estimation across the U.S. is presented.
Complex CSP for chemistry reduction and analysis

Abstract The method of computational singular perturbation for the analysis and reduction of complicated chemical mechanisms has been extended to the complex eigensystem. The characteristic time scale for each species was defined by using the time scales of the independent modes weighted by radical pointers, and the time scale of each species normalized by a characteristic time scale of the system was used as a criterion in determining the quasi-steady-state species. Furthermore, for oscillatory modes the radical pointer and the importance index of the previous computational singular perturbation theory were redefined. Results show that the time scales of chemical species change dramatically and non-monotonically, and the oscillatory modes appear frequently in large chemical reaction mechanisms. The present method was then employed to generate a 4-step and a 10-step reduced mechanism for the high-temperature H2/air and CH4/air oxidation, respectively. The validity of these reduced mechanisms were evaluated based on the responses of the perfectly stirred reactors and the one-dimensional planar propagating premixed flames. Comparisons between the reduced and detailed chemistries over a wide range of pressures and equivalence ratios show good agreement on the flame speed, flame temperature, and flame structure. A software package based on the present algorithm was compiled to generate reduced mechanisms for complex chemical mechanisms. The validity and efficiency of the present algorithm is demonstrated.
The energy driven paradigm of NMOSFET hot carrier effects

As NMOSFET size and voltage are scaled down, the electron energy distribution becomes increasingly dependent only on the applied bias, because of quasi-ballistic transport over the high field region. A new paradigm of NMOSFET hot carrier behavior is proposed here, in which the fundamental driving force is available energy, rather than peak lateral electric field as it is in the lucky electron model (LEM.) This approach allows an experimental determination of S/sub IT/ (the interface state generation cross section) as a function of electron energy.
Do cement lines restrict osteoclastic bone resorption

Bone is constantly remodeled throughout life, but whether the microstructure of the bone affects resorption is unknown. In this present study, longitudinal and transverse devitalized bone slices were cultured in-vitro with rat bone marrow cells to investigate the influence of bone microstructure in directing and regulating bone resorption by osteoclasts. After the 14-day culture period, the average size of resorption areas produced in the longitudinal slices was found to be three times larger than in the transverse slices (p < 0.05). In addition, bone resorption pro-files were consistent with the microstructure of the bone slices. In the longitudinal bone sections resorption areas proceeded more longitudinally than transversely and resorption areas in transverse bone sections were more circular, either contained inside or outside the cement line surrounding the osteon. These results show that the bone microstructure influences osteoclastic resorption and that the cement lines may be the microstructural element that directs and regulates osteoclastic resorption.
Fluctuation smoothing policies are stable for stochastic re-entrant lines

In this paper we establish that all the policies in the class of Fluctuation Smoothing Policies for Mean Cycle Time (FSMCT), proposed in (Lu et al. 1992) and (Lu and Kumar 1993), are stable, in the sense of positive Harris recurrence, for all stochastic re-entrant lines. These constitute the first analytical results on this promising class of scheduling policies which have been shown to substantially reduce the mean and variance of cycle times in stochastic re-entrant lines. Stability is established by showing that the fluid limits corresponding to the FSMCT policies empty in finite time from all suitable initial conditions. A special case of FSMCT policies is the Last Buffer First Serve policy, and its stability is also thus established.
Diffuse radio sources in groups and poor clusters

We have discovered new diffuse radio sources likely associated with groups of galaxies at low redshift (0.01–0.04) and without apparent AGN by using the WENSS and WISH catalogs to perform an unbiased survey. These sources resemble the radio halos, mini-halos, and ‘relics’ of rich clusters, which are thought to be powered by shocks and turbulence from infall into their deep potential wells. Our detection of similar sources within the shallow potential wells of groups of galaxies may challenge this model. Their radio luminosities are approximately two orders of magnitude higher than expected from the extrapolation of the apparent rich cluster radio/X-ray luminosity relation. Even if these sources are misidentified distant clusters, they would lie above the apparent rich cluster radio/X-ray luminosity relation in the literature, suggesting that detections of radio halos and relics thus far may be more biased than previously thought. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Price Advertising by Manufacturers and Dealers

The central prediction of the current paper is that manufacturer price advertising may be a less effective tool for influencing demand than retailer price advertising. We manipulate the source of a price advertisement in an experiment run on a sample of pickup truck owners. Manufacturer price advertising leads to lower indicators of potential demand than dealer price advertising, even among consumers who are experienced with the brand. An econometric analysis of pickup truck sales, price, and advertising data shows that this effect is large enough to detect in market data. Manufacturer and dealer price advertising both increase the demand intercept and the responsiveness of demand to price, but the effects of dealer price advertising are larger. Although dealer price advertising is more effective than manufacturer price advertising, manufacturer price advertising may still be useful to reduce channel conflict. This paper was accepted by Pradeep Chintagunta, marketing.
Pareto-optimal phylogenetic tree reconciliation.

Motivation: Phylogenetic tree reconciliation is a widely used method for reconstructing the evolutionary histories of gene families and species, hosts and parasites and other dependent pairs of entities. Reconciliation is typically performed using maximum parsimony, in which each evolutionary event type is assigned a cost and the objective is to find a reconciliation of minimum total cost. It is generally understood that reconciliations are sensitive to event costs, but little is understood about the relationship between event costs and solutions. Moreover, choosing appropriate event costs is a notoriously difficult problem. Results: We address this problem by giving an efficient algorithm for computing Pareto-optimal sets of reconciliations, thus providing the first systematic method for understanding the relationship between event costs and reconciliations. This, in turn, results in new techniques for computing event support values and, for cophylogenetic analyses, performing robust statistical tests. We provide new software tools and demonstrate their use on a number of datasets from evolutionary genomic and cophylogenetic studies. Availability and implementation: Our Python tools are freely available at www.cs.hmc.edu/~hadas/xscape. Contact: ude.nnocu.rgne@lukum Supplementary information: Supplementary data are available at Bioinformatics online.
Synthesis, characterization and ageing of MgB2

We studied the influence of sample preparation and defects in the superconducting properties samples using atomic ratios of Mg:B=1:1 and Mg:B=1:2. Samples were characterized by SEM, and XRD, and the magnetization properties were examined in a SQUID magnetometer. The presence of Mg vacancies was determined by Rietveld analysis. Most of the samples exhibited sharp superconducting transitions with Tcs between 37–39 K. We found a strong correlation between the crystal strain and the Tc. This strain was related to the presence of Mg vacancies. In addition, results showed that some samples degraded with time when exposed to ambient conditions. In these samples the Tc did not change with time, but the superconducting transition became broader and the Meissner fraction decreased. This effect was only present in samples with poor connectivity between grains and smaller grain sizes. The degradation was related to a surface decomposition as observed by X-ray Photoelectron Spectroscopy. No correlation was found between this effect and the presence of Mg vacancies.
Relative quantum field theory

We highlight the general notion of a relative quantum field theory, which occurs in several contexts. One is in gauge theory based on a compact Lie algebra, rather than a compact Lie group. This is relevant to the maximal superconformal theory in six dimensions.
Earnings Mobility in Times of Growth and Decline : Argentina from 1996 to 2003

Summary In recent years Argentina’s economy has experienced both rapid growth and severe decline. In this paper, we use a series of one-year long panels to study who gained the most in pesos when the economy grew and who lost the most in pesos when the economy contracted. Various considerations led us to expect that mobility would be divergent—that is, that the individuals who started with the highest initial earnings would enjoy the largest earnings gains in pesos. Contrary to expectations and for a wide range of specifications, mobility is found to be mostly convergent, sometimes neutral, and never divergent.
A Resource-Based View of the Firm

Summary The paper explores the usefulness of analysing firms from the resource side rather than from the product side. In analogy to entry barriers and growth-share matrices, the concepts of resource position barrier and resource-product matrices are suggested. These tools are then used to highlight the new strategic options which naturally emerge from the resource perspective.
Quantitative results concerning the utility of explanation-based learning

Abstract In order to solve problems effectively, a problem solver must be able to exploit domain-specific search control knowledge. Although previous research has demonstrated that explanation-based learning is a viable approach for acquiring such knowledge, in practice the control knowledge learned via EBL may not be useful. To be useful, the cumulative benefits of applying the knowledge must outweigh the cumulative costs of testing whether the knowledge is applicable. Unlike most previous systems that use EBL, the PRODIGY system evaluates the costs and benefits of the control knowledge it learns. Furthermore, the system produces useful control knowledge by actively searching for “good” explanations—explanations that can be profitably employed to control problem solving. This paper summarizes a set of experiments measuring the effectiveness of PRODIGY's EBL method (and its components) in several different domains.
Agent-based consumer learning in e-commerce

In the age of information and knowledge, the role of business companies is not only just to sell products and services, but also to educate their consumers. Educating consumers with extremely diversified backgrounds about technical knowledge is an important part of competitive advantage. To succeed, modern companies need to develop the best education technologies and teaching philosophies. Intelligent agents can play the right role in the personalised education of online consumers, because intelligent agents can learn the consumers' learning preferences and styles and recommend the best learning strategies. Educated and informed consumers are smarter and more confident in their buying decisions. This paper investigates using intelligent agents to support consumer learning and proposes an agent-based consumer learning support framework.
Are Cover Stories Effective Contrarian Indicators

Headlines from featured stories in Business Week,Fortune, and Forbes were collected for a 20-year period to determine whether positive stories are associated with superior future performance and negative stories are associated with inferior future performance for the featured company. “Superior” and “inferior” were determined in comparison with an index or another company in the same industry and of the same size. Statistical testing implied that positive stories generally indicate the end of superior performance and negative news generally indicates the end of poor performance.
Finding and ranking knowledge on the semantic web

Swoogle helps software agents and knowledge engineers find Semantic Web knowledge encoded in RDF and OWL documents on the Web. Navigating such a Semantic Web on the Web is difficult due to the paucity of explicit hyperlinks beyond the namespaces in URIrefs and the few inter-document links like rdfs:seeAlso and owl:imports. In order to solve this issue, this paper proposes a novel Semantic Web navigation model providing additional navigation paths through Swoogle's search services such as the Ontology Dictionary. Using this model, we have developed algorithms for ranking the importance of Semantic Web objects at three levels of granularity: documents, terms and RDF graphs. Experiments show that Swoogle outperforms conventional web search engine and other ontology libraries in finding more ontologies, ranking their importance, and thus promoting the use and emergence of consensus ontologies.
Transferring risk preferences from Taxes to investments

Prior studies demonstrate that tax considerations can influence a taxpayer’s investment decisions. By itself, this is not very surprising because the investment decisions in these studies resulted in either increasing or decreasing the tax refund or tax payment. The aim of the present study is to re-examine this relationship in order to isolate the possible psychological effects of year-end tax position. We do this by controlling the economic tax consequences of the investment decisions and by relying on theories of mental accounting for our predictions. Results of two experiments demonstrate that taxpayers are psychologically more likely to hold stocks when they owe a tax payment than when they receive a tax refund, despite the absence of economic tax consequences. Furthermore, this behavior generalizes to stocks with gains and to stocks with losses. The results are consistent with a mental accounting application of prospect theory in which risk preferences in one area (taxes) can potentially influence risk preferences in other areas (investments).