cssi/SciSciGPT-SciSciNet huggingface dataset:
The Intrinsic Shape of Spiral Galaxies in the 2MASS Large Galaxy Atlas

The apparent shapes of spiral galaxies in the Two Micron All Sky Survey Large Galaxy Atlas are used to constrain the intrinsic shapes of their disks. When the distribution of apparent axis ratios is estimated using a nonparametric kernel method, the shape distribution is inconsistent with axisymmetry at the 90% confidence level in the B band and at the 99% confidence level in theKs band. If spirals are subdivided by Hubble type, the late-type spirals (Sc and later) are consistent with axisymmetry, while the earlier spirals are strongly inconsistent with axisymmetry. The distribution of disk ellipticity can be fitted adequately with either a Gaussian or a lognormal distribution.Thebestfitsforthelatespiralsimplyamedianellipticityof � � 0:07intheBbandand � � 0:02intheKsband. Fortheearlierspirals,thebestfitsimplyamedianellipticityof � � 0:18intheBbandand � � 0:30intheKsband.The observed scatter in the Tully-Fisher relation, for both late and early spirals, is consistent with the disk ellipticity measured in theB band. This indicates that excluding spirals of Hubble type earlier than Sc will minimize the intrinsic scatter in the Tully-Fisher relation used as a distance indicator. Subject headingg galaxies: fundamental parameters — galaxies: photometry — galaxies: spiral
Surfaces with occlusions from layered stereo

Although steady progress has been made in recent stereo algorithms, producing accurate results in the neighborhood of depth discontinuities remains a challenge. Moreover, among the techniques that best localize depth discontinuities, it is common to work only with a discrete set of disparity values, hindering the modeling of smooth, non-fronto-parallel surfaces. We propose to estimate scene structure as a set of smooth surface patches. The disparities within each patch are modeled by a spline, while the extent of each patch is represented by a pixelwise labeling of the source images. Disparities and extents are alternately estimated in an iterative, energy minimization framework. Segmentation is via graph cuts, aided by image gradients. Input images are treated symmetrically, and occlusions are addressed explicitly. Promising experimental results are presented.
Identification of the zero-g shape of a space beam

This paper develops an approach for identifying the 0-g shape of a beam/column in a 1-g environment. The determination of the 0-g shape is accomplished by a combination of experiment and analysis. A prototype large space structure beam/column is scaled to laboratory size to demonstrate that the 0-g shape of the structure can be accurately determined in a ground based experiment. Information obtained from the 0-g shape experiment is also used to experimentally measure the stiffness of the beam model.
What is an Asset Price Bubble? An Operational Definition

This paper reviews and analyses the current definitions of bubbles in asset prices. It makes the case that one cannot identify a bubble immediately, but one has to wait a sufficient amount of time to determine whether the previous prices can be justified by subsequent cash flows. The paper proposes an operational definition of a bubble as any time the realised asset return over given future period is more than two standard deviations from its expected return. Using this framework, the paper shows how the great crash of 1929 and 1987—both periods generally characterised as bubbles—prove not to be bubbles but the low point in stock prices in 1932 is a ‘negative bubble.’ The paper then extends this analysis to the internet stocks and concludes that it is virtually certain that it is a bubble.
Application of linear adaptive control to some advanced benchmark examples

Linear adaptive control1–8 is a new approach to adaptive controller design that uses a novel exogenous linear dynamical model of parameter perturbation ‘effects’ and an ordinary linear observer to generate the required adaptive control signal u(t). By this means, the need for a non-linear parameter estimator, as traditionally used in adaptive control, is eliminated and the resulting adaptive controller is completely linear and time-invariant (all controller ‘gains’ are constant). The performance capabilities of linear adaptive controllers have been demonstrated in References 4 and 6–8 using relatively simple examples. In this paper the linear adaptive control technique is applied to several examples having complex forms of plant uncertainty. Computer simulation studies are presented to demonstrate the quality of adaptive performance achieved.
N-Heterocyclic Carbene-Promoted Rauhut]Currier Reactions between Vinyl Sulfones and α,β-Unsaturated Aldehydes.

N-heterocyclic carbenes (NHCs) promote the addition of 1,1-bis(phenylsulfonyl)ethylene to the α-position of α,β-unsaturated aldehydes. The proposed reaction pathway for this Rauhut–Currier-type reaction includes an unusual conjugate addition of an NHC to a bis-vinyl sulfone.
A computer-controlled digital master hearing aid

The design and implementation of a computer-controlled digital master hearing aid (DMHA) have provided a flexible and versatile tool for research in speech processing algorithms to benefit the hearing-impaired. The system includes an IBM PC, programmable antialiasing and reconstruction filters, a digital signal processing board using the TMS320C25 chip, and programmable attenuators and switches. The system was used successfully in a recent study, providing high flexibility, precise fitting of the hearing aid to any hearing loss, and a wide dynamic range. The system can be used to implement and evaluate new algorithms such as enhancement of speech in noise and speech feature extraction. The hardware, software, and FIR filter design are described. >
Alcohol-related predictors of adolescent driving: Gender differences in crashes and offenses

Demographic and alcohol-related data collected from eighth-grade students (age 13 years) were used in logistic regression to predict subsequent first-year driving crashes and offenses (age 17 years). For young men's crashes and offenses, good-fitting models used living situation (both parents or not), parents' attitude about teen drinking (negative or neutral), and the interaction term. Young men who lived with both parents and reported negative parental attitudes regarding teen drinking were less likely to have crashes and offenses. For young women's crashes, a good-fitting model included friends' involvement with alcohol. Young women who reported that their friends were not involved with alcohol were least likely to have crashes. No model predicting young women's offenses emerged.
Detector and telescope development for ProtoEXIST and fine beam measurements of spectral response of CZT detectors

We outline our plan to develop ProtoEXIST, a balloon-borne prototype experiment for the Energetic X-ray Imaging Survey Telescope (EXIST) for the Black Hole Finder Probe. EXIST will consist of multiple wide-field hard X-ray coded-aperture telescopes. The current design of the EXIST mission employs two types of telescope systems: high energy telescopes (HETs) using CZT detectors, and low energy telescopes (LETs) using Si detectors. With ProtoEXIST, we will develop and demonstrate the technologies required for the EXIST HETs. As part of our development efforts, we also present recent laboratory measurements of the spectral response and efficiency variation of imaging CZT detectors on a fine scale (~0.5 mm). The preliminary results confirm the need for multi-pixel readouts and small inter-pixel gaps to achieve uniform spectral response and high detection efficiency across detectors.
What Type of Process Underlies Options? A Simple Robust Test

We develop a simple robust method to distinguish the presence of continuous and discontinuous components in the price of an asset underlying options. Our method examines the prices of at-the-money and out-of-the-money options as the option’s time-to-maturity approaches zero. We show that these prices converge to zero at speeds that depend upon whether the underlying asset price process is purely continuous, purely discontinuous, or a combination of both. We apply the method to S&P 500 index options and ¢nd the existence of both a continuous component and a jump component in the index. TO EFFECTIVELY PRICE OR HEDGE derivative securities, or to understand the behavior of ¢nancial asset prices in general, it is important to know if they are best modeled using a purely continuous process (PC), a pure jump process (PJ), or a combination of both (CJ). We develop a method to distinguish between these possibilities using options written on the asset in question. Speci¢cally, we examine the market prices of at-the-money (ATM) and out-of-the-money (OTM) options as the option’s maturity date approaches the valuation date. While the prices of all ATM and OTM options converge to zero as the time to maturity approaches zero, our theoretical work shows that the speed of convergence diiers across the three possibilities (PC, PJ, or CJ). We can thus identify the type of an asset price process by examining the convergence speeds of these option prices. The simplest approach for determining the type of process governing an asset price is to examine the time series of asset prices directly. However, the discretely sampled paths from the three types of processes look very similar unless the sampling frequency is extremely high. Furthermore, increasing the sampling frequency introduces market microstructure eiects. Since our method does not examine the sample path of the underlying asset directly, it circumvents these di⁄culties. Our method is able to distinguish the type of process governing the price of an asset because diierent types of processes have dramatically diierent implications
Broadband wireless access (BWA) over multi-channel multipoint distribution service (MMDS) frequency band

BWA is a hot technology that has emerged1 to satisfy the growing demand for fixed and mobile high speed data access, multimedia services, video streaming as well as teleconferencing applications. Fixed BWA preliminarily emerged to provide high speed data access for residential and small-medium business market segments, support evolution toward service integration (multimedia, voice), offer cost and performance that are competitive with wired DSL, ISDN an maximize leverage of existing cellular infrastructure. This paper describes a macro-cell/ micro-cell scenario, channel impairments, measurements, and validation performance for fixed-broadband applications in the licensed MMDS (2.5?2.686 GHz) frequency band.
Reporting Regulatory Environments and Earnings Management: U.S. and Non-U.S. Firms Using U.S. GAAP or IFRS

ABSTRACT: Based on data collected from 616 experienced financial officers who use U.S. GAAP or IFRS and are domiciled in the U.S., Europe, or Asia, we examine how reporting standards (U.S. GAAP versus IFRS) and domicile (U.S. versus non-U.S.) affect earnings management (real versus accrual). U.S. firms using U.S. GAAP rely more heavily on real methods than non-U.S. firms that use either IFRS or U.S. GAAP and U.S. firms using IFRS. U.S. firms using U.S. GAAP operate in an environment that encourages real over accruals methods; specifically, U.S. GAAP facilitates detection of earnings management, and enforcement is more effective in the U.S. Further, the likelihood and amount of earnings management do not differ across conditions, suggesting that firms using less accruals earnings management tend to fully compensate by increasing real methods. So stronger reporting environments do not necessarily reduce total earnings management, but instead encourage substitution of real for accruals methods.
The Effect of Human and Financial Capital on the Entrepreneurial Process: An Urban-Rural Comparison of Entrepreneurs in Indiana

Entrepreneurship is a crucial ingredient of economic growth and job creation. Small business start-ups are currently of great interest to many state and local governments including Indiana. With the growing need to stimulate small business development, it is necessary to understand the obstacles faced by entrepreneurs as they attempt to start a business. The results have implications for small business development and university related centers and how they design programs to effectively meet the needs of entrepreneurs participating in small business start-ups. More explicitly, the results show that targeting educational programs by socio-economic and demographic segments would have lead to a better chance of programming success
Probabilistic question answering on the Web

Web-based search engines such as Google and NorthernLight return documents that are relevant to a user query, not answers to user questions. We have developed an architecture that augments existing search engines so that they support natural language question answering. The process entails five steps: query modulation, document retrieval, passage extraction, phrase extraction, and answer ranking. In this article, we describe some probabilistic approaches to the last three of these stages. We show how our techniques apply to a number of existing search engines, and we also present results contrasting three different methods for question answering. Our algorithm, probabilistic phrase reranking (PPR), uses proximity and question type features and achieves a total reciprocal document rank of .20 on the TREC8 corpus. Our techniques have been implemented as a Web-accessible system, called NSIR.
Women's inheritance rights and intergenerational transmission of resources in India

This brief summarizes the women's inheritance rights and intergenerational transmission of resources in India for the period 1986-1994. The author use inheritance patterns over three generations of individuals to assess the impact of changes in the Hindu succession act that grant daughters equal coparcenary birth rights in joint family property that were denied to daughters in the past. The author show that the amendment significantly increased daughter's likelihood to inherit land, but that even after the amendment, substantial bias persists. Our results also indicate a robust increase in educational attainment of daughters, suggesting an alternative channel of wealth transfer.
Axial Resolution of Helical-Orbit Pinhole SPECT With Synchronized and Unsynchronized Motion

Pinhole SPECT imaging is widely used in small-animal imaging. Helical orbits provide better sampling and axial resolution compared to circular ones; however, the unsynchronized axial translation of the imaged object and the camera rotation may cause blurring in the image resulting in poorer resolution. In this study, we investigated the axial resolution for synchronized and unsynchronized motions with a small phantom (Ultra-Micro-Defrise) that closely mimics the size of a mouse. We applied angular-dependent axial mechanical shift corrections that substantially improved axial resolution in this regime. Further, we developed custom-designed electronic circuitry to achieve synchronization of the SPECT scanner and the imaged object. The results show that synchronized motion improves axial resolution especially when the angular step of the scanner's rotation is large.
Built-in self-test (BIST) design of high-speed carry-free dividers

This paper presents the built-in self-test (BIST) design of a C-testable high-speed carry-free divider which can be fully tested by 72 test patterns irrespective of the divider size. Using a graph labeling scheme, the test patterns, expected outputs, and control signals can be represented by sets of labels and generated by a simple circuitry. As a result, test patterns can be easily generated inside chips, responses to test patterns need not to be stored, and use of expensive test equipment is not necessary. Results show that the hardware cost for generating such labels is virtually constant irrespective of the circuit size. For the BIST design of a 64 b C-testable divider, its hardware overhead is less than 5%.
Sign Under the Domino Robinson-Schensted Maps

We generalize a formula obtained independently by Reifegerste and Sjostrand for the sign of a permutation under the classical Robinson-Schensted map to a family of domino Robinson-Schensted algorithms.
Would collective action clauses raise borrowing costs? - an update and additional results

This paper updates earlier findings concerning the impact of collective-action clauses on borrowing costs. It has been argued that only in recent quarters have investors focused on the presence of these provisions, and that, given the international financial institutions’ newfound resolve to bail in investors, they now regard these clauses with trepidation. Extending our data to 1999, we find no evidence of such changes but, rather, the same pattern as before: collective-action clauses raise costs of borrowing for low-rated issuers but reduce them for issuers with high credit ratings. We drop a special case -- Israel -- and show that this has no impact on the results. And we show that the same results hold for sovereign borrowers alone. We argue that these results should reassure those who regard collective action clauses as an important element in the campaign to strengthen the international financial architecture.
Nonparametric identification of positive eigenfunctions

Important objects for analysis in economics, and especially in asset pricing theory, can be expressed as positive eigenfunctions of positive linear operators on function spaces. This note provides nonparametric identification and existence conditions for positive eigenfunctions. These conditions are readily verifiable and have general application to nonparametric models in economics. Two sets of conditions are provided: one set for operators on L p (µ) spaces and a second set for operators on Banach lattices. The use of these results is illustrated by application to the decomposition of stochastic discount factors in dynamic asset pricing models into their permanent and transitory components, in both discrete- and continuous-time environments.
Will Consolidation Improve Sub-National Governments?

Local government size varies dramatically around the world. In Sudan, Cote d'Ivoire, and the United Kingdom, municipalities average more than 125,000 people. Those in many European countries have less than 10,000 people. Countries often consider consolidation of local governments as a means to lower service delivery costs, improve service quality, enhance accountability, improve equity, or expand participation in government. The authors review a number of theoretical arguments and empirical findings concerning the size of sub-national governments. Countries should not presume that amalgamation will solve problems because benefits and costs are situation specific. Success depends on many factors, including getting incentives right for the various players and managing the transition properly. The effects on costs must be examined in terms of all changes occurring with consolidation, including geographic size. Size economies appear service specific and are most likely to result for infrastructure intensive services such as water and sewerage. Size economies are less likely for services such as education that are provided in numerous small production units near the population. Also, the potential for savings depends on other factors, such as willingness to eliminate redundant workers. Consolidation reduces the potential for local government competition, which appears to enhance service quality but not necessarily overall government size. There is some evidence that citizens are more willing to be involved in larger governments, but trust may fall with government size. Larger governments can improve regional planning by handling problems with a broader geographic perspective and giving the government more influence with national policymakers.
Advanced Light Source Master Oscillator

The Master Oscillator of the Advanced Light Source (ALS) operates at a frequency of 499.654 MHz, which is the 328th harmonic of the storage ring. The oscillator is capable of providing up to a maximum of +or-500-kHz frequency deviation for various experimental purposes. Provisions for external signal injection as well as using an external signal source have been designed into the unit. A power distribution system has also been included to provide signals for various parts of the ALS machine and user requirements. The Master Oscillator is made of modules housed in a Euro chassis. >
Weight Control Behaviors among Emerging Adults with Type 1 Diabetes

PurposeThe purpose of this study was to examine the association of weight control behaviors (WCBs) with living and educational situations among emerging adults with type 1 diabetes during the first year after high school graduation.MethodsAmong 184 emerging adults with type 1 diabetes, data were collected every 3 months for 12 months on WCBs, body mass index (BMI), living and educational situations; at baseline and 12 months, on impulse control; and at baseline, on sex, depressive symptoms, and glycemic control. Generalized linear models incorporated repeated measures (0, 3, 6, 9, and 12 months).ResultsNo significant associations existed between WCBs and living or educational situations, when controlling for covariates. More depressive symptoms and higher BMIs were associated with a greater likelihood of involvement in unhealthy WCBs, whereas more depressive symptoms—not higher BMI—were associated with higher odds for involvement in very unhealthy WCBs. Although healthy WCBs were also associated with more...
Core–Shell Catalysts of Metal Nanoparticle Core and Metal–Organic Framework Shell

Encapsulating well-defined nanoparticle catalysts into porous materials to form a core–shell nanostructure can enhance the durability, selectivity, or reactivity of the catalysts and even provide additional functionalities to the catalysts. Using metal–organic frameworks (MOFs) as the encapsulating porous materials has drawn great interest recently because MOFs, as a class of crystalline nanoporous materials, have well-defined pore structures and unique chemical properties. Also, the structures and properties of MOFs are tunable. In this perspective review, we examine recent progress in the development of synthetic methods for metal@MOF core–shell nanostructures as catalysts. Potential directions in the field are also discussed.
PREMIER — PRobabilistic error-correction using Markov inference in errored reads

In this work we present a flexible, probabilistic and reference-free method of error correction for high throughput DNA sequencing data. The key is to exploit the high coverage of sequencing data and model short sequence outputs as independent realizations of a Hidden Markov Model (HMM). We pose the problem of error correction of reads as one of maximum likelihood sequence detection over this HMM. While time and memory considerations rule out an implementation of the optimal Baum-Welch algorithm (for parameter estimation) and the optimal Viterbi algorithm (for error correction), we propose low-complexity approximate versions of both. Specifically, we propose an approximate Viterbi and a sequential decoding based algorithm for the error correction. Our results show that when compared with Reptile, a state-of-the-art error correction method, our methods consistently achieve superior performances on both simulated and real data sets.
Fair Scheduling in Networks Through Packet Election

We consider the problem of designing a fair scheduling algorithm for discrete-time constrained queuing networks. Each queue has dedicated exogenous packet arrivals. There are constraints on which queues can be served simultaneously. This model effectively describes important special instances like network switches, interference in wireless networks, bandwidth sharing for congestion control and traffic scheduling in road roundabouts. Fair scheduling is required because it provides isolation to different traffic flows; isolation makes the system more robust and enables providing quality of service. Existing work on fairness for constrained networks concentrates on flow based fairness. As a main result, we describe a notion of packet based fairness by establishing an analogy with the ranked election problem: packets are voters, schedules are candidates, and each packet ranks the schedules based on its priorities. We then obtain a scheduling algorithm that achieves the described notion of fairness by drawing upon the seminal work of Goodman and Markowitz (1952). This yields the familiar Maximum Weight (MW) style algorithm. As another important result, we prove that the algorithm obtained is throughput optimal. There is no reason a priori why this should be true, and the proof requires nontraditional methods.
Geostatistical Quantification of Geological Information for a Fluvial-Type North Sea Reservoir

Accurate prediction of petroleum reservoir performance requires reliable models of the often complex reservoir heterogeneity. Geostatistical simulation techniques generate multiple realizations of the reservoir model, all equally likely to be drawn. Traditional to geostatistics, geological continuity is represented through the variogram. The variogram is limited in describing complex geological structures as it measures correlation between rock properties at two locations only: it is a two-point statistic. Reservoir analogs such as outcrops can serve as training images depicting the interpreted geological structure. Due to scarcity of well data, the variogram models are often borrowed from such training sets. However, the same training images could be utilized to extract more complex information in the form of multiple-point statistics measuring the joint dependency between multiple locations. This paper compares a traditional variogram-based geostatistical model vs. a novel geostatistical method utilizing multiplepoint statistics borrowed from training images. The comparison is made on the basis of flow performance for a typical North Sea reservoir. To obtain such comparison a ‘‘true’’ reference reservoir is generated using object-based simulation that depicts the complex intertwining of fluvial channels. Next, a different but similar reservoir is generated, termed the ‘‘training reservoir.’’ The latter is used to extract the necessary structural information, be it variograms or multiple-point statistics, to build multiple geostatistical models of the true reservoir conditioned to sparse well data. A waterflood flow scenario with an inverted five-spot pattern is simulated using ECLIPSE on the true reference and the various geostatistical models. Water breakthrough characteristics and water saturation distributions are used for comparison.
Multi-taper transfer function estimation for stimulation artifact removal from neural recordings

The ability to simultaneously stimulate and record from neural tissue is paramount to the creation of a feedback-enabled control system. This stimulation creates additional electrical potential as seen by the recording system. This artifact can be approximated by a linear transfer function of the stimulus current. The computation of the transfer function is complicated by measurement noise and the bias and variance inherent in spectral estimation. We reduce bias and variance by using multi-taper techniques. We demonstrate the use of this transfer function as a method to remove stimulation artifact in the context of neural modulation with applied low-frequency (≪ 100Hz) electric fields in chronically instrumented animals.
Probabilistic key block analysis of a mine ventilation shaft stability – a case study

In this study, the probabilistic key block analysis was applied to evaluate the stability of a mine ventilation shaft developed in a rock mass of granite. The key blocks were identified based on the block theory. The variations of discontinuity orientations were fitted with the Beta distribution and taken into consideration. The key block forming probabilities were analyzed. For simplification of calculations the first-order second-moment (FOSM) approximation was employed for probability estimation. With the considerations of the rock properties as random variables and applications of several statistical analysis tools, the key block failure probabilities, the probabilistic distribution of safety factors, and the probabilistic distribution of potential maximum key block volumes were analyzed. The analysis indicated that although the safety factor calculated based on the mean values of the variables was above 1.0 for the stability of the most critical key block, the block had a considerable probability of ...
Comparison of alternative functional forms in production

Abstract In this paper, a Bayesian approach to choosing between two non-nested multivariate regression systems is developed. The Bayesian approach involves the calculation of the posterior probabilities of alternative hypotheses and formation of a posterior odds ratio. Specific results are obtained for the comparison of a multivariate regression and seemingly unrelated regression model. These odds ratio results are applied to the choice between translog and Fourier flexible form cost share equation systems. When calculated for aggregate U.S. manufacturing cost data, the odds ratios favor the Fourier flexible form over the translog form. Even in small samples, the Fourier series expansion appears to be an effective approximation technique.
Dynamic soil pressures on rigid cylindrical vaults

A critical evaluation is made of the dynamic pressures and the associated forces induced by ground shaking on an upright, circular, rigid vault that is embedded in a uniform viscoelastic stratum of constant thickness and infinite extent in the horizontal plane. Both the vault and the stratum are presumed to be supported on a non- deformable base undergoing a space-invariant, uniform horizontal motion. The effects of both harmonic and earthquake-induced excitations are examined. Simple approximate expressions for the responses of the system are formulated, and comprehensive numerical data are presented which elucidate the underlying response mechanisms and the effects and relative importance of the various parameters involved. The parameters investigated include the height to radius ratio for the vault, the conditions at the vault-medium interface, and the material properties of the stratum. In addition to valuable insights into the response of the particular system being examined, the results presented provide a conceptual framework for the analysis and interpretation of solutions for more involved systems as well.
The Reddest Quasars. II. A Gravitationally Lensed FeLoBAL Quasar

We report the discovery of a z = 2.65 low-ionization iron broad absorption line quasar, FIRST J100424.9+122922, which is gravitationally lensed by a galaxy at z ≈ 0.95. The object was discovered as part of a program to find very red quasars by matching the FIRST radio survey with the Two Micron All Sky Survey in the near-infrared. J100424.9+122922 is the second lensed system to be found in this program, suggesting that many gravitational lenses are probably missed from conventional optical quasar surveys. We have made a simple lens model and a rough estimate of the reddening in the immediate environment of the quasar which suggests that the quasar is intrinsically very luminous and is accreting at close to the Eddington limit of its ~109 M⊙ black hole. The lensing galaxy has a small amount of dust, which is responsible for some excess reddening observed in the fainter image of the quasar, but is otherwise a fairly typical massive elliptical galaxy. We model the selection effects working against the detection of red quasars in both lensed and unlensed samples. We show that these selection effects are very effective at removing even lightly reddened high-redshift quasars from magnitude-limited samples, whether they are lensed or not. This suggests that the red quasar population in general could be very large, and in particular the class of iron broad absorption line quasars of which J100424.9+122922 is a member may be much larger than their rarity in magnitude-limited samples would suggest.
Incentives and creativity: evidence from the academic life sciences

Despite its presumed role as an engine of economic growth, we know surprisingly little about the drivers of scientific creativity. We exploit key differences across funding streams within the academic life sciences to estimate the impact of incentives on the rate and direction of scientific exploration. Specifically, we study the careers of investigators of the Howard Hughes Medical Institute (HHMI), which tolerates early failure, rewards long-term success, and gives its appointees great freedom to experiment, and grantees from the National Institutes of Health (NIH), who are subject to short review cycles, predefined deliverables, and renewal policies unforgiving of failure. Using a combination of propensity-score weighting and difference-in-differences estimation strategies, we find that HHMI investigators produce high-impact articles at a much higher rate than a control group of similarly accomplished NIH-funded scientists. Moreover, the direction of their research changes in ways that suggest the program induces them to explore novel lines of inquiry.
Forward and non-forward symplectic integrators in solving classical dynamics problems

Forward time step integrators are splitting algorithms with only positive splitting coefficients. When used in solving physical evolution equations, these positive coefficients correspond to positive time steps. Forward algorithms are essential for solving time-irreversible equations that cannot be evolved using backward time steps. However, forward integrators are also better in solving time-reversible equations of classical dynamics by tracking as closely as possible the physical trajectory. This work compares in detail various forward and non-forward fourth-order integrators using three, four, five and six force evaluations. In the case of solving the 2D Kepler orbit, all non-forward integrators are optimized by simply minimizing the size of their backward time steps
Enlargement of the liver in diabetes mellitus.

Medical textbooks are brief in their reference to the enlargement of the liver that is now and then found in cases of diabetes mellitus. Friedrich Umber 1 says: "The liver in diabetic patients ordinarily is enlarged when the disease is of long duration. Whether hyperemia, fat infiltration or incipient cirrhosis is the cause often cannot be settled intra vitam." Von Noorden and Isaac 2 refer to the symptom in the following words: "Doubtless, in many diabetic patients there is a moderate enlargement of the liver. Slight tenderness and increased consistency of the organ is most often demonstrated in these patients." However, von Noorden further states that in 25 per cent of the cases the enlarged liver was accompanied by other signs of circulatory disturbances, and he considers the hard and enlarged liver an accidental complication in diabetes mellitus. Joslin 3 makes no mention whatever of enlarged liver as a symptom
The Effects of the Tax Deduction for Postsecondary Tuition: Implications for Structuring Tax-Based Aid

Abstract The tax deduction for tuition potentially increases investments in education at minimal administrative cost. We assess whether it actually does this using regression discontinuity on the income cutoffs that govern eligibility. Although many eligible households take the maximum, we find no evidence that it affects attending college, attending full-time, attending four-year college, the resources experienced, the amount paid, or student loans. Our analysis suggests that the deduction's inefficacy may be due to salience, timing, and the method of receipt. We argue that the deduction might increase college-going if it were modified in simple ways that would not increase potential costs but would make it more likely to relax liquidity constraints and be perceived as a price change (which it is) as opposed to an income change. We find that households who would be just above a cut-off manage their incomes to fall slightly below it. Such income management generates bias due to reverse causality. We choose optimal “doughnut-holes” that trade-off bias and statistical power.
The insurance sector in the Middle East and North Africa : challenges and development agenda

This paper studies the causes of the low development of the insurance sector in the Middle East and North African (MENA) region, particularly for long term insurance. The paper shows that life and non-life premiums, as well as assets, are very low relative to expected levels given per capita income and demographic characteristics, and examines the causes of such poor performance. There is a wide range of factors constraining the development of the industry, including the absence of mandatory insurance in key areas, the predominant presence of the state in some countries, gaps in regulation and supervision, unsupportive tax regimes, fragmented market structures, a chronic lack of suitably skilled people, as well as the absence of products that conform with cultural/religious preferences, especially in the case of life insurance. The lack of development of the insurance sector is a matter of concern, as research shows that the sector can contribute to both financial and economic development. Key recommendations to accelerate the development of the sector include wider introduction of mandatory insurance lines that have clear positive externalities, continuing the privatization process for government owned insurers, employing non capital techniques to force rationalization of insurance sectors with too many small and inefficient players, removing tax distortions, taking steps to stabilize motor third party liability markets (typically the largest line of business), strengthening reporting and disclosure, regulating banc-assurance, improving consumer protection, further developing Takaful long term insurance ('Family Insurance'), and establishing regional centers of excellence for skills development.
THE STEPPENWOLF: A PROPOSAL FOR A HABITABLE PLANET IN INTERSTELLAR SPACE

Rogue planets have been ejected from their planetary system. We investigate the possibility that a rogue planet could maintain a liquid ocean under layers of thermally insulating water ice and frozen gas as a result of geothermal heat flux. We find that a rogue planet of Earth-like composition and age could maintain a subglacial liquid ocean if it were ≈3.5 times more massive than Earth, corresponding to ≈8 km of ice. Suppression of the melting point by contaminants, a layer of frozen gas, or a larger complement of water could significantly reduce the planetary mass that is required to maintain a liquid ocean. Such a planet could be detected from reflected solar radiation, and its thermal emission could be characterized in the far-IR if it were to pass within O(1000) AU of Earth.
Ethical Issues in the Field of Probation

The present paper is an attempt to discuss some of the important ethical issues confronting the field of probation. Special attention is focussed on the potential conflicts that arise from the two major roles that traditionally are assigned to probation officers: that of helping agent, and that of enforcer of legal conditions. Other ethical problems arise from the pressures placed on the probation officer as a result of the organizational structure of a given department and the level of government in which it is located. Those located on the national level must deal with ethical issues that differ from those on the state level, which in turn are different from those found on the local levels.In addition, the influence of contemporary conditions on daily decisions made by probation officers raise important ethical considerations. Such factors as lack of adequate resources in a period of recession, the increased incidence of violent offenders in the population of probationers, and caseloads that prohibit ad...
Mechanisms of Stereopsis in Monkey Visual Cortex

A substantial proportion of neurons in the striate and prestriate cortex of monkeys have stereoscopic properties; that is, they respond differentially to binocular stimuli that are known in humans to provide cues for stereoscopic depth perception. Stereoscopic neurons, as these cells may be called, are selective for horizontal positional disparity (i.e., display disparity selectivity) and for the textural correlation between images over their receptive fields (i.e., they show correlation selectivity). Many neurons have tuned disparity response profiles that collectively cover the entire range of physiological disparities. Neurons with peak responses at or about the zero disparity ("tuned zero neurons," excitatory or inhibitory) have narrow and symmetrical profiles. Neurons that are tuned to larger disparities, either crossed ("tuned near neurons") or uncrossed ("tuned far neurons"), have broader excitatory profiles that are asymmetrically wider toward the smaller disparities, and commonly include an inhibitory component about the zero disparity. Other stereoscopic neurons have reciprocal profiles ("near" or "far" neurons, respectively) in the sense that they respond with excitation to crossed or uncrossed disparities, and with suppression to disparities of opposite sign. Stereoscopic neurons can also signal the textural correlation between paired retinal images by giving different responses to random-dot patterns that have, and to those that do not have, the same dot distribution over the neuron's left and right receptive fields. Tuned-zero excitatory neurons characteristically respond to uncorrelation with suppression; tuned-zero inhibitory neurons, with excitation; and both types give the opposite responses to correlated stereopatterns. Neurons selective for nonzero disparities, both tuned and reciprocal, also give excitatory responses to uncorrelated stimuli, but these responses are smaller and more variable than those evoked by correlated patterns at the effective disparities. These findings suggest that stereoscopic neurons in the visual cortex of the macaque comprise three operational systems: (1) a zero-disparity system that is involved in fine depth discrimination with the obligatory singleness of vision, and the maintenance of vergence; and (2) a near-, and (3) a far-disparity system that together signal qualitative estimates of depth with double vision, and vergence responses to large disparities.
Knightian Analysis of the Vickrey Mechanism

We analyze the Vickrey mechanism for auctions of multiple identical goods when the players have both Knightian uncertainty over their own valuations and incomplete preferences. In this model, the Vickrey mechanism is no longer dominant-strategy, and we prove that all dominant-strategy mechanisms are inadequate. However, we also prove that, in undominated strategies, the social welfare produced by the Vickrey mechanism in the worst case is not only very good, but also essentially optimal
Real exchange rate targeting and macroeconomic instability

Abstract Using an optimizing model of a small open economy, this paper studies the macroeconomic effects of PPP rules whereby the government increases the devaluation rate when the real exchange rate—defined as the price of tradables in terms of nontradables—is below its long-run level and reduces the devaluation rate when the real exchange rate is above its long-run level. The paper shows that the mere existence of such a rule can generate aggregate instability due to self-fulfilling expectations. The result is shown to obtain in both flexible- and sluggish-price environments.
Genes, peoples, and languages

The genetic history of a group of populations is usually analyzed by reconstructing a tree of their origins. Reliability of the reconstruction depends on the validity of the hypothesis that genetic differentiation of the populations is mostly due to population fissions followed by independent evolution. If necessary, adjustment for major population admixtures can be made. Dating the fissions requires comparisons with paleoanthropological and paleontological dates, which are few and uncertain. A method of absolute genetic dating recently introduced uses mutation rates as molecular clocks; it was applied to human evolution using microsatellites, which have a sufficiently high mutation rate. Results are comparable with those of other methods and agree with a recent expansion of modern humans from Africa. An alternative method of analysis, useful when there is adequate geographic coverage of regions, is the geographic study of frequencies of alleles or haplotypes. As in the case of trees, it is necessary to summarize data from many loci for conclusions to be acceptable. Results must be independent from the loci used. Multivariate analyses like principal components or multidimensional scaling reveal a number of hidden patterns and evaluate their relative importance. Most patterns found in the analysis of human living populations are likely to be consequences of demographic expansions, determined by technological developments affecting food availability, transportation, or military power. During such expansions, both genes and languages are spread to potentially vast areas. In principle, this tends to create a correlation between the respective evolutionary trees. The correlation is usually positive and often remarkably high. It can be decreased or hidden by phenomena of language replacement and also of gene replacement, usually partial, due to gene flow.
Electronic structure calculations for LaNi5 and LaNi5H7: energetics and elastic properties

Abstract Density functional calculations of the electronic structure and enthalpy of formation Δ H of LaNi 5 and LaNi 5 H 7 are reported. Single-crystal elastic constants and Voigt–Reuss–Hill polycrystalline moduli were calculated for both materials using a stress-based least-squares fitting methodology. We obtain Δ H (0 K)=−40 kJ/mol H 2 for the hydride at zero temperature. Incorporating a Debye estimate of the phonon contribution we find Δ H (298 K)∼−39 kJ/mol/H 2 , a value that compares favorably with experimental determinations of −32 to −35 kJ/mol/H 2 . Our results indicate that the H–Ni and H–La interactions in the hydride are primarily metallic with a small ionic component. The calculated elastic moduli are in excellent accord with single-crystal measurements on LaNi 5 and with available data for polycrystalline samples of the parent and hydride.
On the modular invariance of mass eigenstates and CP violation

We investigate the modular transformation properties of observable (light) flelds in heterotic orbifolds, in the light of recent calculations of CP-violating quantities. Measurable quantities must be modular invariant functions of string moduli, even if the light flelds are not invariant. We show that physical invariance may arise by patching smooth functions that are separately noninvariant. CP violation forhTi on the unit circle, which requires light and heavy states to mix under transformation, is allowed in principle, although the Jarlskog parameter JCP(T) must be amended relative to previous results. However, a toy model of modular invariant mass terms indicates that the assumption underlying these results is unrealistic. In general the mass eigenstate basis is manifestly modular invariant and coupling constants are smooth invariant functions of T, thus CP is unbroken on the unit circle. We also discuss the status of CP-odd quantities when CP is a discrete gauge symmetry, and point out a link with baryogenesis.
Noise Performance of a Cross-Product AFC with Decision Feedback for DPSK Signals

This paper presents a derivation of the noise performance of the cross-product AFC with decision feedback (CPAFCDF). This is an AFC loop configured for use with differentially phase-shift-keyed (DPSK) signals and gives excellent performance in noise.