cssi/SciSciGPT-SciSciNet huggingface dataset:
The Association Between Auditor Changes and Reporting Lags

. This paper examines audit report lags and earnings announcement lags for a sample of firms that switched auditors. We investigate whether audit report and earnings announcement lags are associated with the timing of auditor changes in relation to firms' fiscal year-ends. It is hypothesized that firms which replace their auditor early (late) in the fiscal year do so for positive (negative) reasons and experience shorter (longer) reporting lags. Conflicts over reporting issues can be difficult to resolve and consequently lead to reporting delays. In other cases, clients may be more concerned about adhering to customary reporting practices or improving reporting timeliness. These are likely to be considerations in auditor realignment decisions and are predictably reflected in the timing of the auditor change. Resume. Les auteurs s'interessent aux decalages dans la production des rapports des verificateurs et dans la publication des benefices, pour un echantillon d'entreprises ayant change de verificateurs. Ils se demandent si ces decalages sont relies au choix du moment du changement de verificateurs par rapport a la date de cloture de l'exercice. Selon leur hypothese, les entreprises qui remplacent leurs verificateurs tot (tard) dans l'exercice le font pour des raisons positives (negatives), et les decalages enregistres dans la production de l'information sont plus courts (plus longs). Les conflits touchant les questions relatives a l'information a fournir peuvent etre difficiles a resoudre et, en consequence, conduire a des retards dans la publication de l'information. Dans d'autres cas, les entreprises clientes peuvent etre davantage preoccupees par le respect des methodes coutumieres de presentation de l'information ou par l'acceleration de la publication de l'information. Ces facteurs sont susceptibles d'entrer en ligne de compte dans les decisions de reorientation des verificateurs, et il est a prevoir qu'ils se refleteront dans le choix du moment du changement de verificateurs.
Non‐Markovian electron dynamics in nanostructures coupled to dissipative contacts

In quasiballistic semiconductor nanostructures, carrier exchange between the active region and dissipative contacts is the mechanism that governs relaxation. In this paper, we present a theoretical treatment of transient quantum transport in quasiballistic semiconductor nanostructures, which is based on the open system theory and valid on timescales much longer than the characteristic relaxation time in the contacts. The approach relies on a model interaction between the current-limiting active region and the contacts, given in the scattering-state basis. We derive a non-Markovian master equation for the irreversible evolution of the active region’s many-body statistical operator by coarse-graining the exact dynamical map over the contact relaxation time. In order to obtain the response quantities of a nanostructure under bias, such as the potential and the charge and current densities, the non-Markovian master equation must be solved numerically t ' '
Difference in Th1 and Th17 Lymphocyte Adhesion to Endothelium

T cell subset-specific migration to inflammatory sites is tightly regulated and involves interaction of the T cells with the endothelium. Th17 cells often appear at different inflammatory sites than Th1 cells, or both subsets appear at the same sites but at different times. Differences in T cell subset adhesion to endothelium may contribute to subset-specific migratory behavior, but this possibility has not been well studied. We examined the adhesion of mouse Th17 cells to endothelial adhesion molecules and endothelium under flow in vitro and to microvessels in vivo and we characterized their migratory phenotype by flow cytometry and quantitative RT-PCR. More Th17 than Th1 cells interacted with E-selectin. Fewer Th17 than Th1 cells bound to TNF-α-activated E-selectin-deficient endothelial cells, and intravital microscopy studies demonstrated that Th17 cells engage in more rolling interactions with TNF-α-treated microvessels than Th1 cells in wild-type mice but not in E-selectin-deficient mice. Th17 adhesion to ICAM-1 was dependent on integrin activation by CCL20, the ligand for CCR6, which is highly expressed by Th17 cells. In an air pouch model of inflammation, CCL20 triggered recruitment of Th17 but not Th1 cells. These data provide evidence that E-selectin- and ICAM-1-dependent adhesion of Th17 and Th1 cells with endothelium are quantitatively different.
What Happens to the Careers of European Workers When Immigrants "Take Their Jobs"?

Following a representative longitudinal sample of native European residents over the period 1995–2001, we identify the effect of the inflows of immigrants on natives’ career, employment, and wages. We control for individual, country-year, occupation group-year, and occupation group-country heterogeneity and shocks, and construct an imputed inflow of the foreign-born population that is exogenous to local demand shocks. We find that native European workers are more likely to move to occupations associated with higher skills and status when a larger number of immigrants enters their labor market. We find no evidence of an increase in their probability of becoming unemployed.
Quadratic electro-optic effect in a novel nano-optical polymer (iodine-doped polyisoprene)

Quadratic electro-optic effect in a novel nano-optical polymer (iodine-doped polyisoprene) has been measured. The magnitude of the Kerr coefficient is large, about 66 times that of nitrobenzene at 632 nm.
A Tree System Approach for Fingerprint Pattern Recognition

The purpose of this paper is to demonstrate how a syntactic approach and, in particular, a tree system may be used to represent and classify fingerprint patterns. The fingerprint impressions are subdivided into sampling squares which are preprocessed and postprocessed for feature extraction. A set of regular tree languages is used to describe the fingerprint patterns and a set of tree automata is used to recognize the coded patterns. In order to infer the structural configuration of the encoded fingerprints, a grammatical inference system is developed. This sytem utilizes a simple procedure to infer the numerous substructures and relies on a reachability matrix and a man-machine interactive technique for the inference of complex structures. The 92 fingerprint impressions were used to test the proposed approach. A set of 193 tree grammars was inferred from each sampling square of the 4 × 4 sampling matrix which is capable of generating about 2 × 1034 classes for the fingerprint patterns.
How the global structure of protein interaction networks evolves

Two processes can influence the evolution of protein interaction networks: addition and elimination of interactions between proteins, and gene duplications increasing the number of proteins and interactions. The rates of these processes can be estimated from available Saccharomyces cerevisiae genome data and are sufficiently high to affect network structure on short time-scales. For instance, more than 100 interactions may be added to the yeast network every million years, a fraction of which adds previously unconnected proteins to the network. Highly connected proteins show a greater rate of interaction turnover than proteins with few interactions. From these observations one can explain (without natural selection on global network structure) the evolutionary sustenance of the most prominent network feature, the distribution of the frequency P(d) of proteins with d neighbours, which is broad-tailed and consistent with a power law, that is: P(d) proportional, variant d (-gamma).
Processor verification using efficient reductions of the logic of uninterpreted functions to propositional logic

The logic of Equality with Uninterpreted Functions (EUF) provides a means of abstracting the manipulation of data by a processor when verifying the correctness of its control logic. By reducing formulas in this logic to propositional formulas, we can apply Boolean methods such as ordered Binary Decision Diagrams (BDDs) and Boolean satisfiability checkers to perform the verification. We can exploit characteristics of the formulas describing the verification conditions to greatly simplfy the propostional formulas generated. We identify a class of terms we call “p-terms” for which equality comparisons can only be used in monotonically positive formulas. By applying suitable abstractions to the hardware model, we can express the functionality of data values and instruction addresses flowing through an instruction pipeline with p-terms. A decision procedure can exploit the restricted uses of p-terms by considering only “maximally diverse” interpretations of the associated function symbols, where every function application yields a different value execept when constrainted by functional consistency. We present two methods to translate formulas in EUF into propositional logic. The first interprets the formula over a domain of fixed-length bit vectors and uses vectors of propositional variables to encode domain variables. The second generates formulas encoding the conditions under which pairs of terms have equal valuations, introducing propostional variables to encode the equality relations between pairs of terms. Both of these approaches can exploit maximal diversity to greatly reduce the number of propositional variables that need to be introduced and to reduce the overall formula sizes. We present experimental results demonstrating the efficiency of this approach when verifying pipelined processors using the method proposed by Burch and Dill. Exploiting positive equality allows us to overcome the experimental blow-up experienced previously when verifying microprocessors with load, store, and branch instructions.
Perceptions and Worry about Hazards at Work: Unions, Contract Maintenance, and Job Control in the U.S. Petrochemical Industry

Union statements and journalist accounts have tied workers' fears of accidents to the increasing use of subcontractors at U.S. petrochemical plants. In this case study of workers at a chemical facility in Louisiana, we explore who perceives and worries about chemical exposures and explosions in the work place and why. Perceptions of chemical exposures were highest among union members, contract workers, and those with low job control, whereas perception of explosions was highest among those reporting being rushed or overworked. Contract workers appear to be more worried about hazards in the industry than direct-hire employees.
Regiospecific acylation reactions of imidazo[1,5-a]pyridine

Abstract Imidazo [1,5-alpyridine ( 1 ) displays dual reactivity through two condition-dependent reaction pathways. Regiospecific acylation occurs with benzoyl chloride at the 1-position under Friedl-Crafts conditions to afford 3 or at the 3-position via a postulated, stabilized ylid 5 under thermal or triethylamine-mediated acylation conditions to give 2 .
Control engineers workbench--A methodology for microcomputer implementation of controls

The concept of the Control Engineers Workbench (CEWB) is discussed, and the Control Engineers Workbench is defined as a set of software tools that are integrated to assist with the implementation of real-time control systems. The control system is assumed to consist of both analog and microcomputer electronics (which, in part, may reside in VLSI silicon). The workbench therefore supports, most importantly, the software engineering activities. The basis for the Control Engineers Workbench is established, and a methodology based upon the concept of a design environment is proposed. Within the environment, two key tools are introduced: information management of the requirements documentation and the use of a state language [1] to describe the high-level hardware/software architecture.
Robust stability: perturbed systems with perturbed equilibria

Studies robustness properties of a large class of nonlinear systems by addressing the following question: given a nonlinear system with specified asymptotically stable equilibria, under what conditions will a perturbed model of the system possess asymptotically stable equilibria which are close (in distance) to the asymptotically stable equilibria of the unperturbed system? In arriving at their results, the authors establish robustness stability results for the perturbed systems considered herein and determine conditions which ensure the existence of asymptotically stable equilibria of the perturbed system which are near the asymptotically stable equilibria of the original unperturbed system. These results involve quantitative estimates of the distance between the corresponding equilibrium points of the unperturbed and perturbed systems. The authors apply the above results in the analysis of a large class of systems which arise in VLSI implementations of nonlinear (transistor) circuits. >
Multiwavelength Observations of Pulsar Wind Nebulae

The extended nebulae formed as pulsar winds expand into their surroundings provide information about the composition of the winds, the injection history from the host pulsar, and the material into which the nebulae are expanding. Observations from across the electromagnetic spectrum provide constraints on the evolution of the nebulae, the density and composition of the surrounding ejecta, the geometry of the central engines, and the long-term fate of the energetic particles produced in these systems. Such observations reveal the presence of jets and wind termination shocks, time-varying compact emission structures, shocked supernova ejecta, and newly formed dust. Here I provide a broad overview of the structure of pulsar wind nebulae, with specific examples from observations extending from the radio band to very-high-energy γ-rays that demonstrate our ability to constrain the history and ultimate fate of the energy released in the spin-down of young pulsars.
First order symmetrizable hyperbolic formulations of Einstein's equations including lapse and shift as dynamical fields

First-order hyperbolic systems are promising as a basis for numerical integration of Einstein's equations. In previous work, the lapse and shift have typically not been considered part of the hyperbolic system and have been prescribed independently. This can be expensive computationally, especially if the prescription involves solving elliptic equations. Therefore, including the lapse and shift in the hyperbolic system could be advantageous for numerical work. In this paper, two first-order symmetrizable hyperbolic systems are presented that include the lapse and shift as dynamical fields and have only physical characteristic speeds.
CHARACTER DEGREE SUMS AND REAL REPRESENTATIONS OF FINITE CLASSICAL GROUPS OF ODD CHARACTERISTIC

sum of the dimensions of the real representations of each of these groups. We also show that if G is a classical connected group defined over Fq with connected center, with dimension d and rank r, then the sum of the degrees of the irreducible characters of G(Fq) is bounded above by (q +1 ) (d+r)/2 . Finally, we show that if G is any connected reductive group defined over Fq, for any q, the sum of the degrees of the irreducible
Sports at Work: Anticipated and Persistent Correlates of Participation in High School Athletics

Do former high school athletes make better employees than nonathletes? Two studies examine how participation in competitive youth sports appears to be relevant for early-career job prospects as well as late-in-life outcomes. In the short run, Study 1 shows that people expect former student-athletes to display significantly more leadership, self-confidence, and self-respect than those who were active outside of sports—such as being in the band or on the yearbook staff. In the long run, Study 2 uses biodata to discover that men who participated in varsity-level high school sports an average of 60 years earlier appeared to demonstrate higher levels of leadership and enjoyed higher-status careers. Surprisingly, these ex-athletes also exhibited more prosocial behavior than nonathletes—they more frequently volunteered time and donated to charity. These findings open a wide range of possibilities regarding how one’s participation in competitive youth sports might influence the development of important skills and...
A modification of Einstein–Schrödinger theory that contains both general relativity and electrodynamics

We modify the Einstein–Schrodinger theory to include a cosmological constant Λ z which multiplies the symmetric metric, and we show how the theory can be easily coupled to additional fields. The cosmological constant Λ z is assumed to be nearly cancelled by Schrodinger’s cosmological constant Λ b which multiplies the nonsymmetric fundamental tensor, such that the total Λ = Λ z + Λ b matches measurement. The resulting theory becomes exactly Einstein–Maxwell theory in the limit as |Λ z | → ∞. For |Λ z | ~ 1/(Planck length)2 the field equations match the ordinary Einstein and Maxwell equations except for extra terms which are < 10−16 of the usual terms for worst-case field strengths and rates-of-change accessible to measurement. Additional fields can be included in the Lagrangian, and these fields may couple to the symmetric metric and the electromagnetic vector potential, just as in Einstein–Maxwell theory. The ordinary Lorentz force equation is obtained by taking the divergence of the Einstein equations when sources are included. The Einstein–Infeld–Hoffmann (EIH) equations of motion match the equations of motion for Einstein–Maxwell theory to Newtonian/Coulombian order, which proves the existence of a Lorentz force without requiring sources. This fixes a problem of the original Einstein–Schrodinger theory, which failed to predict a Lorentz force. An exact charged solution matches the Reissner–Nordstrom solution except for additional terms which are ~10−66 of the usual terms for worst-case radii accessible to measurement. An exact electromagnetic plane-wave solution is identical to its counterpart in Einstein–Maxwell theory.
Optimized emission in nanorod arrays through quasi-aperiodic inverse design

We investigate a new class of quasi-aperiodic nanorod structures for emission enhancement. Using inverse design we identify one optimized structure which produces a 1.48X.
KLEINIAN GROUPS IN HIGHER DIMENSIONS

This is a survey of higher-dimensional Kleinian groups, i.e., discrete isometry groups of the hyperbolic n-space ℍ n for n ≥ 4. Our main emphasis is on the topological and geometric aspects of higher-dimensional Kleinian groups and their contrast with the discrete groups of isometry of ℍ3.
A combined direct, indirect, and variable structure method for robust adaptive control

Direct methods and indirect methods for the adaptive control of linear plants with unknown parameters are currently well known. Methods for combining direct and indirect methods have also been suggested. In the paper the latter method is combined with the variable structure method. New adaptive laws are suggested which overcome the principal drawbacks of the variable structure method. While the direct and indirect components of the new method assure stability, the variable structure component improves the transient response of the system. Simulation results are presented to show that the overall system is asymptotically stable in the ideal case, and exhibits robustness and improved performance in the presence of perturbations. >
INFORMATION, DUOPOLY AND COMPETITIVE MARKETS: A SENSITIVITY ANALYSIS*

Abstract : Implicit in the discussion of markets and competition are differing conditions on information as the number of competitors changes. In particular the market with many competitors has long been considered as an entity with relatively low levels of information. People react to the average market price and aggregate inventories. Personalities disappear each individual adjusts to the impersonal market that supplies him aggregate information. In contrast with the many person market, duopolistic behavior, bilateral monopoly bargaining and oligopolistic behavior in general appears to depend upon detailed information. The other individuals in the market cannot be safely regarded as part of an anonymous aggregate. Specific information about individuals may be of importance. The paper is devoted to exploring the variations of information conditions for an extremely simple set of duopoly models. (Author)
Complete deletion of Apc results in severe polyposis in mice

The adenomatous polyposis coli (APC) gene product is mutated in the vast majority of human colorectal cancer. APC negatively regulates the WNT pathway by aiding in the degradation of βCatenin, the transcription factor activated downstream of WNT signaling. APC mutations result in β-Catenin stabilization and constitutive WNT pathway activation leading to aberrant cellular proliferation. APC mutations associated with colorectal cancer commonly fall in a region of the gene termed the mutation cluster region and result in expression of an N-terminal fragment of the APC protein. Biochemical and molecular studies have revealed localization of APC/Apc to different sub-cellular compartments and various proteins outside of the WNT pathway that associate with truncated APC/Apc. These observations and genotypephenotype correlations have led to the suggestion that truncated APC bears neomorphic and/or dominant-negative function that support tumor development. To investigate this possibility, we have generated a novel allele of Apc in the mouse that yields complete loss of Apc protein. Our studies reveal that whole-gene deletion of Apc results in more rapid tumor development than the Apc Min truncation. Furthermore, we found that adenomas bearing truncated Apc had increased β-catenin activity compared to tumors lacking Apc protein, which could lead to context-dependent inhibition of tumorigenesis.
Generating hard satisfiable formulas by hiding solutions deceptively

To test incomplete search algorithms for constraint satisfaction problems such as 3- SAT, we need a source of hard, but satisfiable, benchmark instances. A simple way to do this is to choose a random truth assignment A, and then choose clauses randomly from among those satisfied by A. However, this method tends to produce easy problems, since the majority of literals point toward the "hidden" assignment A. Last year, Achlioptas, Jia and Moore proposed a problem generator that cancels this effect by hiding both A and its complement A (Achlioptas, Jia, & Moore, 2004). While the resulting formulas appear to be just as hard for DPLL algorithms as random 3-SAT formulas with no hidden assignment, they can be solved by WalkSAT in only polynomial time. Here we propose a new method to cancel the attraction to A, by choosing a clause with t > 0 literals satisfied by A with probability proportional to q>t for some q < 1. By varying q, we can generate formulas whose variables have no bias, i.e., which are equally likely to be true or false; we can even cause the formula to "deceptively" point away from A. We present theoretical and experimental results suggesting that these formulas are exponentially hard both for DPLL algorithms and for incomplete algorithms such as WalkSAT.
Combined oral contraceptives and body weight: do oral contraceptives cause weight gain? A primate model

background: The aim of this study was to determine if oral contraceptive (OC) use affects body weight, body composition and metabolism in primates. methods: Reproductive-age female rhesus monkeys of normal and obese BMI were studied to document baseline weight stability, then treated continuously with an OC (dosed to achieve equivalent human serum levels for a 30 mg ethinyl estradiol/150 mg levonorgestrel preparation) for 237 days. Monkeys were monitored for changes in body weight, levels of physical activity (measured by a triaxial Actical accelerometer), food/caloric intake, percent body fat (dual energy X-ray absorptiometry, DEXA) and metabolism (24 h metabolic rate and serum metabolic substrate and hormone concentrations). results: All 10 monkeys completed the study protocol with no adverse events. While body weight (20.73% change) and percent body fat (21.78% change) of the normal BMI group did not significantly decrease from baseline, obese monkeys showed a significant decrease in body weight (28.58% change, P , 0.01) and percent body fat (212.13% change P ¼ 0.02) with OC treatment. In both the obese (P ¼ 0.03) and the normal BMI (P ¼ 0.01) groups, there was a significant increase in basal metabolic rate with OC use. No changes were seen in food intake, activity level or % lean muscle mass with OC use for either BMI-based group.
Energy-Efficient Communication via Feedback

We propose a feedback optimization framework to minimize the total energy consumption in point-to-point wireless communication links. The energy cost of both the forward link and the feedback link are taken into account. Given the energy consumption profile of both links, we minimize error probability subject to the total energy budget and a delay constraint. The proposed framework is based on a multi-phase feedback scheme in which a transmission, if decoded incorrectly, is followed by a retransmission with boosted energy. We use this framework to show that the gain of utilizing feedback is highly dependent on the energy consumption profile of the links and the total available energy. In particular, we identify scenarios in which the use of feedback significantly increases the energy efficiency, as well as scenarios where, surprisingly, the use of feedback is strictly suboptimal as compared to communication without feedback.
A convenient set of comoving cosmological variables and their application

We present a set of cosmological variables, called "supercomoving variables," which are particularly useful for describing the gas dynamics of cosmic structure formation. For ideal gas with gamma=5/3, the supercomoving position, velocity, density, temperature, and pressure are constant in time in a uniform, isotropic, adiabatically expanding universe. Expressed in terms of these supercomoving variables, the cosmological fluid conservation equations and the Poisson equation closely resemble their noncosmological counterparts. This makes it possible to generalize noncosmological results and techniques to cosmological problems, for a wide range of cosmological models. These variables were initially introduced by Shandarin for matter-dominated models only. We generalize supercomoving variables to models with a uniform component corresponding to a nonzero cosmological constant, domain walls, cosmic strings, a nonclumping form of nonrelativistic matter (e.g. massive nettrinos), or radiation. Each model is characterized by the value of the density parameter Omega0 of the nonrelativistic matter component in which density fluctuation is possible, and the density parameter OmegaX of the additional, nonclumping component. For each type of nonclumping background, we identify FAMILIES within which different values of Omega0 and OmegaX lead to fluid equations and solutions in supercomoving variables which are independent of Omega0 and OmegaX. We also include the effects of heating, radiative cooling, thermal conduction, viscosity, and magnetic fields. As an illustration, we describe 3 familiar cosmological problems in supercomoving variables: the growth of linear density fluctuations, the nonlinear collapse of a 1D plane-wave density fluctuation leading to pancake formation, and the Zel'dovich approximation.
Old and New Fields on Super Riemann Surfaces

The `new fields' or `superconformal functions' on N = 1 super Riemann surfaces introduced recently by Rogers and Langer are shown to coincide with the Abelian differentials (plus constants), viewed as a subset of the functions on the associated N = 2 super Riemann surface. We confirm that, as originally defined, they do not form a super vector space.
CSMA/CN: carrier sense multiple access with collision notification

A wireless transmitter learns of a packet loss and infers collision only after completing the entire transmission. If the transmitter could detect the collision early [such as with carrier sense multiple access with collision detection (CSMA/CD) in wired networks], it could immediately abort its transmission, freeing the channel for useful communication. There are two main hurdles to realize CSMA/CD in wireless networks. First, a wireless transmitter cannot simultaneously transmit and listen for a collision. Second, any channel activity around the transmitter may not be an indicator of collision at the receiver. This paper attempts to approximate CSMA/CD in wireless networks with a novel scheme called CSMA/CN (collision notification). Under CSMA/CN, the receiver uses PHY-layer information to detect a collision and immediately notifies the transmitter. The collision notification consists of a unique signature, sent on the same channel as the data. The transmitter employs a listener antenna and performs signature correlation to discern this notification. Once discerned, the transmitter immediately aborts the transmission. We show that the notification signature can be reliably detected at the listener antenna, even in the presence of a strong self-interference from the transmit antenna. A prototype testbed of 10 USRP/GNU Radios demonstrates the feasibility and effectiveness of CSMA/CN.
The congenital bicuspid aortic valve can experience high-frequency unsteady shear stresses on its leaflet surface

The bicuspid aortic valve (BAV) is a common congenital malformation of the aortic valve (AV) affecting 1% to 2% of the population. The BAV is predisposed to early degenerative calcification of valve leaflets, and BAV patients constitute 50% of AV stenosis patients. Although evidence shows that genetic defects can play a role in calcification of the BAV leaflets, we hypothesize that drastic changes in the mechanical environment of the BAV elicit pathological responses from the valve and might be concurrently responsible for early calcification. An in vitro model of the BAV was constructed by surgically manipulating a native trileaflet porcine AV. The BAV valve model and a trileaflet AV (TAV) model were tested in an in vitro pulsatile flow loop mimicking physiological hemodynamics. Laser Doppler velocimetry was used to make measurements of fluid shear stresses on the leaflet of the valve models using previously established methodologies. Furthermore, particle image velocimetry was used to visualize the flow fields downstream of the valves and in the sinuses. In the BAV model, flow near the leaflets and fluid shear stresses on the leaflets were much more unsteady than for the TAV model, most likely due to the moderate stenosis in the BAV and the skewed forward flow jet that collided with the aorta wall. This additional unsteadiness occurred during mid- to late-systole and was composed of cycle-to-cycle magnitude variability as well as high-frequency fluctuations about the mean shear stress. It has been demonstrated that the BAV geometry can lead to unsteady shear stresses under physiological flow and pressure conditions. Such altered shear stresses could play a role in accelerated calcification in BAVs.
Bringing natural products into the fold – exploring the therapeutic lead potential of secondary metabolites for the treatment of protein-misfolding-related neurodegenerative diseases

Covering: up to June 2010 This review, citing 187 references, is an account of natural products exhibiting bioactive properties relevant to the treatment of protein aggregation-related neurodegenerative diseases (e.g., Huntington's, Parkinson's, and prion diseases). We have compared the chemical properties of secondary metabolite leads to compounds that are in current clinical use for treating central nervous system targets. This comparison revealed that natural products possess many of the desirable traits found in central nervous system-acting agents. It was also observed that the discovery of secondary metabolite leads from marine and microbial sources lags far behind the substantial discoveries emerging from plants. We have concluded this review by providing details concerning many of the most promising secondary metabolite leads that have been identified with therapeutic applications specific to the treatment of Huntington's, Parkinson's and prion diseases. We have also summarized compounds that have more generalized bioactivities that are favorable for treating a broad range of neurodegenerative disorders (i.e., anti-inflammatory, prevention of glutamate-induced neurotoxicity, neurotrophic activity, and inhibition of monoamine oxidase activity).
Linear algebraic groups as parameterized Picard-Vessiot Galois groups

We show that a linear algebraic group is the Galois group of a parameterized Picard-Vessiot extension of k(x), x ′ = 1, for certain differential fields k, if and only if its identity component has no one dimensional quotient as a linear algebraic group.
THE DIFFIE-HELLMAN KEY EXCHANGE PROTOCOL AND NON-ABELIAN NILPOTENT GROUPS

In this paper we study a key exchange protocol similar to the Diffie-Hellman key exchange protocol, using abelian subgroups of the automorphism group of a non-abelian nilpotent group. We also generalize group no. 92 of the Hall-Senior table [16] to an arbitrary prime p and show that, for those groups, the group of central automorphisms is commutative. We use these for the key exchange we are studying.
The Seed-Fungus of Lolium temulentum, L., the Darnel

It has long been known that the grains of the Darnel contain a poisonous body (Lolium), which can be extracted by ether. This substance has marked toxic action on rabbits and certain carnivorous animals, and is said to induce vomiting and other unpleasant symptoms in man, but to affect pigs, cattle, and geese but little, or not at all. In 18981 attention was drawn to the fact that a large percentage (80-100 per cent.) of the grains of this grass contain a definite fungus-mycelium, always situated in a definite layer of the seed, i. e. , in the remains of the nucellus, just outside the aleurone-layer of the endosperm.
Does the market recognize IT-enabled competitive advantage?

There is a belief that the payoffs from investments in information technology (IT) are difficult to recognize, and therefore a sustained competitive advantage from an IT-enabled strategy is difficult to distinguish from a temporary competitive advantage. We develop a model to test whether market participants are able to recognize a sustained competitive advantage due to an IT-enabled strategy, and test the model empirically. We find that a competitive advantage due to an IT-enabled strategy is discernable by market participants, and as apparent as a competitive advantage obtained through other means.
Grain contracting strategies: the case of durum wheat

One of the impacts of higher prices along with greater volatility in futures, basis, and spreads is that there is pressure for greater use of cash contracts for grain. There is a wide array of cash contracts with varying terms that pose strategic alternatives for buyers, particularly as they seek to use contracting as an element of risk mitigation. Durum is a crop where many issues and challenges are apparent. Durum is more risky than competing crops with greater price, yield, and quality risk. In contrast to competing crops, futures do not exist, cross hedging is poor, and forward contracting has been used minimally. The purpose of this study is to develop a model to analyze alternative contracting strategies in the case of durum wheat. The authors introduce alternative pricing features, and explore contract terms and analyze them in terms of risk and return to growers using stochastic efficiency with respect to a function. Results indicate that contracts reduce risks to growers, and are preferred to no contracting of durum. In general, the results varied across grower risk aversions. [EconLit classifications: Q120; C150; D800]. © 2010 Wiley Periodicals, Inc.
PNEUMOTHORAX AND POSTURE.

The last mentioned fact may perhaps find its explanation in the following statements: the two pleural cavities are separated by the layers of the anterior and posterior mediastinal septa. Between the two lies the heart. In the dog, the posterior seems to be somewhat tougher than the anterior septum, and somewhat more fixed and tense. With violent respiratory movements, it is the anterior septum which more especially flaps to and fro and bulges when an opening in the pleura has been made, and it is the anterior septum which is so apt to rupture and thus cause double pneumothorax and the death of the animal. When the dog is on its back, the heart falls backward and the bulging of the anterior mediastinal septum is made more easy. It is different when the animal is on its belly. The heart falls toward the anterior chest wall and thus supports the anterior septum: hence the flapping of the septum, the interference with the respiration of the lung on the sound side, the bulging on expiration on the open side, can not so readily occur. The danger of the open pneumothorax is greatly lessened when the animal is in the prone position. In the supine position the danger of the pneumothorax is due to the falling back of the heart and thus facilitating the rupture of the fragile anterior mediastinal septum; the danger is therefore obviated by fixing the pericardium to the anterior wall of the thorax.
Stigma as related to mental disorders.

Individuals with mental illness receive harsh stigmatization, resulting in decreased life opportunities and a loss of independent functioning over and above the impairments related to mental disorders themselves. We begin our review with a multidisciplinary discussion of mechanisms underlying the strong propensity to devalue individuals displaying both deviant behavior and the label of mental illness. Featured is the high potential for internalization of negative perceptions on the part of those with mental disorders—i.e., self-stigmatization. We next focus on several issues of conceptual and practical relevance: (a) stigma against less severe forms of mental disorder; (b) the role of perceptions of dangerousness related to mental illness; (c) reconciliation of behavioral research with investigations of explicit and implicit attitudes; (d) evolutionary models and their testability; (e) attributional accounts of the causes of mental illness, especially to personal control versus biogenetic factors; and (f)...
Analytical Solutions for Steady and Transient Temperatures in Oil Pipelines

Abstract: This paper presents three analytical solutions to the heat transfer problem where an insulated pipe transports fluids in an environment with a longitudinal temperature gradient. The first solution is for steady fluid flow condition. Closed form equations for temperature profile in the longitudinal direction and total heat transfer across the insulation are presented. The second solution is for fluid flow start-up process. A transient solution for temperature distribution in the pipe is presented. The third solution is for the process of changing flow rate (shutting-down is a special case). Again a transient solution for temperature distribution in the pipe is presented. An example application of the steady fluid flow solution is also shown in this paper. In this case, the mathematical model was used for prediction of temperature distribution in an oxidation reactor installed in a space station.
Two-level power combining using a lens amplifier

A two-level quasi-optical power combiner is presented. The combiner consists of a grid oscillator which feeds a transmission amplifier at its focal point. The focal-point feed improves power coupling efficiency over that of a plane-wave feed. A linear 7-element lens amplifier array demonstrates 29 dB of isolation and a 30/spl deg/ continuous scan angle with less than 1 dB power variation at 9.7 GHz. A 23-element two-dimensional lens amplifier array fed by a grid oscillator demonstrates 5.7 dB gain and a 30/spl deg/ scan angle with less than 2 dB power variation at 10.25 GHz. When horn-fed, the 24-element lens has an isolation of 17-21 dB over a 3% bandwidth. The grid oscillator, as well as receive and transmit sections of the lens amplifiers, are each fabricated on single substrates, making monolithic millimeter-wave integration of each component possible. >
Politics, Economics, and Politics Again

This essay reconsiders the meaning of politics. It argues that economics offers theory and language that can contribute to the understanding and fulfillment of political life by facilitating analysis of the public interest. However, economics does not provide an escape from political disagreement, whether based on inevitable differences of interest or of belief, or on self-serving efforts to advance one cause at the expense of another. As a language of discourse, economics is shown to be compatible with a broader conception of human nature than is sometimes claimed by its practitioners or acknowledged by its critics.
The Significance of Tax Law Asymmetries: An Empirical Investigation

This study uses tax return data for U. S. nonfinancial corporations for the period 1971–1982 to estimate the importance of restrictions on the ability of firms to use tax credits and to obtain refunds for tax losses. Our results suggest that the incidence of such unused tax benefits increased substantially during the early 1980s, though we do not find these increases attributable to increased investment incentives during that period. We present estimates of the marginal tax rate on interest payments which take into account unused tax benefits and emphasize the importance of distinguishing current tax payments from marginal tax rates in estimating the incentive to invest.
Symmetry of Bound and Antibound States in the Semiclassical Limit

Motivated by a recent numerical observation we show that in one dimensional scattering a barrier separating the interaction region from infinity implies approximate symmetry of bound and antibound states. We also outline the numerical procedure used for an efficient computation of one dimensional resonances.
What Have We Learned from the Deepwater Horizon Disaster? An Economist’s Perspective

Follow this and additional works at: http://cbe.miis.edu/joce Part of the Agricultural and Resource Economics Commons, Economic Policy Commons, Economics Commons, Energy Policy Commons, Environmental Policy Commons, Natural Resource Economics Commons, Natural Resources and Conservation Commons, Natural Resources Management and Policy Commons, Nature and Society Relations Commons, and the Water Resource Management Commons
Transforming Insect Electromyograms into Pneumatic Muscle Control

Biological inspiration has a history of advancing the field of robotics. Increasingly, robots are also being used in the modeling of biological systems. In this paper, we use recorded cockroach electromyograms (EMGs) to drive artificial muscle (braided pneumatic actuator) activation and thereby robot joint motion, in an effort to model the transformation from EMG to behavior in the animal. A muscle activation model was developed that transforms EMGs recorded from behaving cockroaches into appropriate commands for the robot. The transform is implemented by multiplying the EMG by an input gain thus generating an input pressure signal, which is used to drive a one-way closed-loop pressure controller. The actuator then can be modeled as a capacitance with input rectification. The actuator exhaust valve is given a leak rate, making the transform a leaky integrator for air pressure, which drives the output force of the actuator. We find parameters of this transform by minimizing the difference between the robot motion produced and that observed in the cockroach. Results from evaluation on reduced-amplitude cockroach angle data strongly suggest that braided pneumatic actuators can be used as part of a physical model of a biological system.
The Policy Elasticity

Executive SummaryThis paper illustrates how one can use causal effects of a policy change to measure its welfare impact without decomposing them into income and substitution effects. Often, a single causal effect suffices: the impact on government revenue. Because these responses vary with the policy in question, I term them policy elasticities to distinguish them from Hicksian and Marshallian elasticities. The model also formally justifies a simple benefit-cost ratio to measure the marginal value of public funds corresponding to non-budget neutral policies. Using existing causal estimates, I apply the framework to five policy changes: top income tax rate, Earned Income Tax Credit (EITC) generosity, food stamps, job training, and housing vouchers.
The reasonable effectiveness of mathematics in the natural sciences

Mathematics and its relation to the physical universe have been the topic of speculation since the days of Pythagoras. Several different views of the nature of mathematics have been considered: Realism—mathematics exists and is discovered; Logicism—all mathematics may be deduced through pure logic; Formalism—mathematics is just the manipulation of formulas and rules invented for the purpose; Intuitionism—mathematics comprises mental constructs governed by self evident rules. The debate among the several schools has major importance in understanding what Eugene Wigner called, The Unreasonable Effectiveness of Mathematics in the Natural Sciences. In return, this ‘Unreasonable Effectiveness’ suggests a possible resolution of the debate in favor of Realism. The crucial element is the extraordinary predictive capacity of mathematical structures descriptive of physical theories.
Inheritance of Interorganizational Workflows: How to Agree to Disagree Without Loosing Control?

Internet-based technology, E-commerce, and the rise of networked virtual enterprises have fueled the need for interorganizational workflows. Although XML allows trading partners to exchange information, it cannot be used to coordinate activities in different organizational entities. Business-to-business processes are hindered by the lack of a common language to support collaboration. This paper describes the P2P (Public-To-Private) approach which addresses one of the most notorious problems in this domain: How to design an interorganizational workflow such that there is local autonomy without compromising the consistency of the overall process. The approach uses a notion of inheritance and consists of three steps: (1) create a common understanding of the interorganizational workflow by specifying the shared public workflow, (2) partition the public workflow over the organizational entities involved, and (3) for each organizational entity: create a private workflow which is a subclass of the relevant part of the public workflow. This paper shows that this approach avoids typical anomalies in business-to-business collaboration (e.g., deadlocks and livelocks) and yields an interorganizational workflow which is guaranteed to realize the behavior specified in the public workflow.
Progress towards intersubband quantum-box lasers for highly efficient continuous wave operation in the mid-infrared

Intersubband quantum-box (IQB) lasers, which are devices consisting of 2-D arrays of ministacks (i.e., 2-4 stages) intersubband QB emitters have been proposed as alternatives to 30-stage quantum-cascade (QC) devices, for efficient room-temperature (RT) emission in the mid-infrared (4-6 µm) wavelength range. Preliminary results include: 1) the design of devices for operation with 50% wallplug efficiency at RT; 2) realization of a novel type of QC device: the deep-well (DW) QC laser, that has demonstrated at λ µm low temperature sensitivity of the threshold current, a clear indication of suppressed carrier leakage; 3) the formation of 2-D arrays at nanopoles by employing nanopatterning and dry etching; 4) the formation of 40 nm-diameter, one-stage IQB structures on 100 nm centers by preferential regrowth via metal-organic vapor phase epitaxy (MOVPE).