cssi/SciSciGPT-SciSciNet huggingface dataset:
Understanding and Deterring Misreporting in Nonprofits: The Joint Effects of Pay Level and Penalty Type

We experimentally examine how nonprofit pay levels affect nonprofit managers’ misreporting and how different types of penalties deter such behavior. In the absence of penalties for misreporting, we find similar levels of, but different mechanisms for, misreporting by managers who select into lower- versus higher-paying nonprofits. Specifically, lower-paying nonprofits attract mission-focused managers who misreport to advance their nonprofit’s mission and justify doing so by their personal sacrifice of wealth, whereas higher-paying nonprofits attract a majority of self-focused managers who justify misreporting by focusing on their personal outcomes. Because managers who select into their nonprofit at different pay levels have different motivation and justification for misreporting, we predict and find that penalizing the nonprofit is more effective in deterring misreporting in lower-paying nonprofits, while penalizing the manager is more effective in higher-paying nonprofits. Our study contributes to theory on the behavioral drivers of nonprofit misreporting and informs practice of ways to deter it.
Economically high-order unstructured-grid methods: Clarification and efficient FSR schemes

In this paper, we clarify reconstruction-based discretization schemes for unstructured grids and discuss their economically high-order versions, which can achieve high-order accuracy under certain conditions at little extra cost. The clarification leads to one of the most economical approaches: the flux-and-solution-reconstruction (FSR) approach, where highly economical schemes can be constructed based on an extended kappa-scheme combined with economical flux reconstruction formulas, achieving up to fifth-order accuracy (sixth-order with zero dissipation) when a grid is regular. Various economical FSR schemes are presented and their formal orders of accuracy are verified by numerical experiments.
Comparing Feedback Linearization and Adaptive Backstepping Control for Airborne Orientation of Agile Ground Robots using Wheel Reaction Torque

In this paper, two nonlinear methods for stabilizing the orientation of a Four-Wheel Independent Drive and Steering (4WIDS) robot while in the air are analyzed, implemented in simulation, and compared. AGRO (the Agile Ground Robot) is a 4WIDS inspection robot that can be deployed into unsafe environments by being thrown, and can use the reaction torque from its four wheels to command its orientation while in the air. The goal of this work is to decrease the stabilization time and reject disturbances using nonlinear control methods. Model-based Feedback Linearization (FL) was added to PD control to compensate for nonlinear dynamics. However, with external disturbances, model uncertainty, and sensor noise the FL+PD controller does not guarantee stability. As an alternative, a backstepping controller was designed based on Lyapunov analysis with adaptive compensation for external disturbances, model uncertainty, and sensor offset. A simulation was written using the full nonlinear dynamics of AGRO in an isotropic steering configuration in which control authority over its pitch and roll are equalized. The PD+FL control method was compared to the backstepping control method using the same initial conditions in simulation. Both the backstepping controller and the PD+FL controller stabilized the system within 250 ms. The adaptive backstepping controller was also able to compensate for offset noisy sinusoidal disturbances through an adaptation law.
A Joint MLE Approach to Large-Scale Structured Latent Attribute Analysis

Structured latent attribute models (SLAMs) are a family of discrete latent variable models widely used in education, psychology, and epidemiology to model multivariate categorical data. A SLAM assu...
On properness of K-moduli spaces and optimal degenerations of Fano varieties

We establish an algebraic approach to prove the properness of moduli spaces of K-polystable Fano varieties and reduce the problem to a conjecture on destabilizations of K-unstable Fano varieties. Specifically, we prove that if the stability threshold of every K-unstable Fano variety is computed by a divisorial valuation, then such K-moduli spaces are proper. The argument relies on studying certain optimal destabilizing test configurations and constructing a $$\Theta $$ -stratification on the moduli stack of Fano varieties.
Perfectly-reflecting guided-mode-resonant photonic lattices possessing Mie modal memory.

Resonant periodic nanostructures provide perfect reflection across small or large spectral bandwidths depending on the choice of materials and design parameters. This effect has been known for decades, observed theoretically and experimentally via one-dimensional and two-dimensional structures commonly known as resonant gratings, metamaterials, and metasurfaces. The physical cause of this extraordinary phenomenon is guided-mode resonance mediated by lateral Bloch modes excited by evanescent diffraction orders in the subwavelength regime. In recent years, hundreds of papers have declared Fabry-Perot or Mie resonance to be the basis of the perfect reflection possessed by periodic metasurfaces. Treating a simple one-dimensional cylindrical-rod lattice, here we show clearly and unambiguously that Mie resonance does not cause perfect reflection. In fact, the spectral placement of the Bloch-mode-mediated zero-order reflectance is primarily controlled by the lattice period by way of its direct effect on the homogenized effective-medium refractive index of the lattice. In general, perfect reflection appears away from Mie resonance. However, when the lateral leaky-mode field profiles approach the isolated-particle Mie field profiles, the resonance locus tends towards the Mie resonance wavelength. The fact that the lattice fields “remember” the isolated particle fields is referred here as “Mie modal memory.” On erasure of the Mie memory by an index-matched sublayer, we show that perfect reflection survives with the resonance locus approaching the homogenized effective-medium waveguide locus. The results presented here will aid in clarifying the physical basis of general resonant photonic lattices.
Adversarial attacks in consensus-based multi-agent reinforcement learning

Recently, many cooperative distributed multiagent reinforcement learning (MARL) algorithms have been proposed in the literature. In this work, we study the effect of adversarial attacks on a network that employs a consensus-based MARL algorithm. We show that an adversarial agent can persuade all the other agents in the network to implement policies that optimize an objective that it desires. In this sense, the standard consensus-based MARL algorithms are fragile to attacks.
Yang–Mills at strong vs. weak coupling: Renormalons, OPE and all that

I discuss various situations in which perturbative expansions are used in Yang–Mills theories with asymptotic freedom and establish the limits of its applicability.
Reducing subspace models for large-scale covariance regression.

We develop an envelope model for joint mean and covariance regression in the large p, small n setting. In contrast to existing envelope methods, which improve mean estimates by incorporating estimates of the covariance structure, we focus on identifying covariance heterogeneity by incorporating information about mean-level differences. We use a Monte Carlo EM algorithm to identify a low-dimensional subspace that explains differences in both means and covariances as a function of covariates, and then use MCMC to estimate the posterior uncertainty conditional on the inferred low-dimensional subspace. We demonstrate the utility of our model on a motivating application on the metabolomics of aging. We also provide R code that can be used to develop and test other generalizations of the response envelope model.
Private Linear Transformation: The Individual Privacy Case

This paper considers the single-server Private Linear Transformation (PLT) problem when individual privacy is required. In this problem, there is a user that wishes to obtain $L$ linear combinations of a D-subset of messages belonging to a dataset of $K$ messages stored on a single server. The goal is to minimize the download cost while keeping the identity of every message required for the computation individually private. We focus on the setting in which the matrix of coefficients pertaining to the required linear combinations is the generator matrix of a maximum distance separable code. We establish lower and upper bounds on the capacity of PLT with individual privacy, where the capacity is defined as the supremum of all achievable download rates. We show that our bounds are tight under certain divisibility conditions. In addition, we present lower bounds on the capacity of the settings in which the user has a prior side information about a subset of messages.
Identification of novel genetic susceptibility loci for thoracic and abdominal aortic aneurysms via genome-wide association study using the UK Biobank Cohort.

Background Thoracic aortic aneurysm (TAA) and abdominal aortic aneurysm (AAA) are known to have a strong genetic component. Methods and results In a genome-wide association study (GWAS) using the UK Biobank, we analyzed the genomes of 1,363 individuals with AAA compared to 27,260 age, ancestry, and sex-matched controls (1:20 case:control study design). A similar analysis was repeated for 435 individuals with TAA compared to 8,700 controls. Polymorphism with minor allele frequency (MAF) >0.5% were evaluated. We identified novel loci near LINC01021, ATOH8 and JAK2 genes that achieved genome-wide significance for AAA (p-value <5x10-8), in addition to three known loci. For TAA, three novel loci in CTNNA3, FRMD6 and MBP achieved genome-wide significance. There was no overlap in the genes associated with AAAs and TAAs. Additionally, we identified a linkage group of high-frequency variants (MAFs ~10%) encompassing FBN1, the causal gene for Marfan syndrome, which was associated with TAA. In FinnGen PheWeb, this FBN1 haplotype was associated with aortic dissection. Finally, we found that baseline bradycardia was associated with TAA, but not AAA. Conclusions Our GWAS found that AAA and TAA were associated with distinct sets of genes, suggesting distinct underlying genetic architecture. We also found association between baseline bradycardia and TAA. These findings, including JAK2 association, offer plausible mechanistic and therapeutic insights. We also found a common FBN1 linkage group that is associated with TAA and aortic dissection in patients who do not have Marfan syndrome. These FBN1 variants suggest shared pathophysiology between Marfan disease and sporadic TAA.
Anisotropic to Isotropic Phase Transitions in the Early Universe

Department of Physics and AstronomyUniversity of Delaware, Newark, Delaware 19716.We propose that the early Universe was not Lorentz symmetric and that a gradual transition to the Lorentzsymmetric phase occurred. An underlying form of the Dirac equation hints to such a transition for fermions.Fermions were coupled to space-time in a non-trivial mannersuch that they were massless in the Lorentz vio-lating phase. The partition function is used as a transfer matrix to model this transition on a two level thermody-namics system that describes how such a transition might have occurred. The system that models this transitionevolves, with temperature, from a state of large to negligible entropy and this is interpreted as describing thetransition to a state with Lorentz symmetry. In addition to this, analogy is created with the properties of thissystem to describe how the ﬁelds were massless and how a baryo n asymmetry can be generated in this model.I. INTRODUCTION
Windowed backoff algorithms for WiFi: theory and performance under batched arrivals

Binary exponential backoff (BEB) is a decades -old algorithm for coordinating access to a shared channel. In modern networks, BEB plays a crucial role in WiFi and other wireless communication standards. Despite this track record, well-known theoretical results indicate that under bursty traffic, BEB yields poor makespan, and superior algorithms are possible. To date, the degree to which these findings impact performance in wireless networks has not been examined. Here, we investigate a challenging case for BEB: a single burst (batch) of packets that simultaneously contend for access to a wireless channel. Using Network Simulator 3, we incorporate into IEEE 802.11g several newer algorithms that have theoretically-superior makespan guarantees. Surprisingly, we discover that these newer algorithms underperform BEB. Investigating further, we identify as the culprit a common abstraction regarding the cost of collisions. Our experimental results are complemented by analytical arguments that the number of collisions—and not solely makespan—is an important metric to optimize. We propose a new theoretical model that accounts for the cost of collisions, and derive new asymptotic bounds on the makespan for BEB and the newer backoff algorithms that align with our experimental findings. Finally, we argue that these findings have implications for the design of backoff algorithms in wireless networks.
ac Susceptometry of 2D van der Waals Magnets Enabled by the Coherent Control of Quantum Sensors

A novel function for quantum sensing is demonstrated, in which NV magnetometry is extended to the dynamic character of magnetism, enabling ac and dc study of spintronic materials at the nanoscale.
Autonomous Navigation for Quadrupedal Robots with Optimized Jumping through Constrained Obstacles

Quadrupeds are strong candidates for navigating challenging environments because of their agile and dynamic designs. This paper presents a methodology that extends the range of exploration for quadrupedal robots by creating an end-to-end navigation framework that exploits walking and jumping modes. To obtain a dynamic jumping maneuver while avoiding obstacles, dynamically-feasible trajectories are optimized offline through collocation-based optimization where safety constraints are imposed. Such optimization schematic allows the robot to jump through window-shaped obstacles by considering both obstacles in the air and on the ground. The resulted jumping mode is utilized in an autonomous navigation pipeline that leverages a search-based global planner and a local planner to enable the robot to reach the goal location by walking. A state machine together with a decision making strategy allows the system to switch behaviors between walking around obstacles or jumping through them. The proposed framework is experimentally deployed and validated on a quadrupedal robot, a Mini Cheetah, to enable the robot to autonomously navigate through an environment while avoiding obstacles and jumping over a maximum height of 13 cm to pass through a window-shaped opening in order to reach its goal. (Video11Experimental videos can be found at https://youtu.be/5pzJ8U7YvGc.)
Pointwise ergodic theorems for higher levels of mixing

We prove strengthenings of the Birkhoff Ergodic Theorem for weakly mixing and strongly mixing measure preserving systems. We show that our pointwise theorem for weakly mixing systems is strictly stronger than the Wiener-Wintner Theorem. We also show that our pointwise Theorems for weakly mixing and strongly mixing systems characterize weakly mixing systems and strongly mixing systems respectively. The methods of this paper also allow one to prove an enhanced pointwise ergodic theorem for other levels of the ergodic hierarchy such as ergodicity and mild mixing but not K-mixing. The author plans to include these additional pointwise ergodic theorems in his thesis.
Distinct "driving" versus "modulatory" influences of different visual corticothalamic pathways.

Summary Higher-order (HO) thalamic nuclei interact extensively and reciprocally with the cerebral cortex. These corticothalamic (CT) interactions are thought to be important for sensation and perception, attention, and many other important brain functions. CT projections to HO thalamic nuclei, such as the visual pulvinar, originate from two different excitatory populations in cortical layers 5 and 6, whereas first-order nuclei (such as the dorsolateral geniculate nucleus; dLGN) only receive layer 6 CT input. It has been proposed that these layer 5 and layer 6 CT pathways have different functional influences on the HO thalamus, but this has never been directly tested. By optogenetically inactivating different CT populations in the primary visual cortex (V1) and recording single-unit activity from V1, dLGN, and pulvinar of awake mice, we demonstrate that layer 5, but not layer 6, CT projections drive visual responses in the pulvinar, even while both pathways provide retinotopic, baseline excitation to their thalamic targets. Inactivating the superior colliculus also suppressed visual responses in the same subregion of the pulvinar, demonstrating that cortical layer 5 and subcortical inputs both contribute to HO visual thalamic activity—even at the level of putative single neurons. Altogether, these results indicate a functional division of “driver” and “modulator” CT pathways from V1 to the visual thalamus in vivo.
Strong solutions to a fourth order exponential PDE describing epitaxial growth

Abstract In this paper we prove the global existence of a strong solution to the initial boundary value problem for the exponential partial differential equation ∂ t u − Δ e − Δ u + e − Δ u − 1 = 0 . The equation was proposed as a continuum model for epitaxial growth of crystal surfaces on vicinal surfaces with evaporation and deposition effects [6] . Our investigations reveal that we must control the size of both ‖ e − Δ u ( x , 0 ) ‖ W 2 , 2 ( Ω ) and ‖ e Δ u ( x , 0 ) ‖ ∞ , Ω suitably to achieve our results. Related results in [8] , [10] were established via the Weiner algebra framework. Here we offer a totally new approach, which seems to shed more light on the nature of exponential nonlinearity.
Learning Generative Deception Strategies in Combinatorial Masking Games.

Deception is a crucial tool in the cyberdefence repertoire, enabling defenders to leverage their informational advantage to reduce the likelihood of successful attacks. One way deception can be employed is through obscuring, or masking, some of the information about how systems are configured, increasing attacker’s uncertainty about their targets. We present a novel game-theoretic model of the resulting defender-attacker interaction, where the defender chooses a subset of attributes to mask, while the attacker responds by choosing an exploit to execute. The strategies of both players have combinatorial structure with complex informational dependencies, and therefore even representing these strategies is not trivial. First, we show that the problem of computing an equilibrium of the resulting zero-sum defender-attacker game can be represented as a linear program with a combinatorial number of system configuration variables and constraints, and develop a constraint generation approach for solving this problem. Next, we present a novel highly scalable approach for approximately solving such games by representing the strategies of both players as neural networks. The key idea is to represent the defender’s mixed strategy using a deep neural network generator, and then using alternating gradient-descent-ascent algorithm, analogous to the training of Generative Adversarial Networks. Our experiments, as well as a case study, demonstrate the efficacy of the proposed approach.
Predictive Representations in Hippocampal and Prefrontal Hierarchies.

As we navigate the world, we use learned representations of relational structures to explore and to reach goals. Studies of how relational knowledge enables inference and planning are typically conducted in controlled small-scale settings. It remains unclear, however, how people use stored knowledge in continuously unfolding navigation, e.g., walking long distances in a city. We hypothesized that multiscale predictive representations guide naturalistic navigation in humans, and these scales are organized along posterior-anterior prefrontal and hippocampal hierarchies. We conducted model-based representational similarity analyses of neuroimaging data collected while male and female participants navigated realistically long paths in virtual reality. We tested the pattern similarity of each point-along each path-to a weighted sum of its successor points within predictive horizons of different scales. We found that anterior PFC showed the largest predictive horizons, posterior hippocampus the smallest, with the anterior hippocampus and orbitofrontal regions in between. Our findings offer novel insights into how cognitive maps support hierarchical planning at multiple scales.Significance StatementWhenever we navigate the world, we represent our journey at multiple horizons: from our immediate surroundings to our distal goal. How are such cognitive maps at different horizons simultaneously represented in the brain? Here, we applied a reinforcement learning-based analysis to neuroimaging data acquired while participants virtually navigated their hometown. We investigated neural patterns in the hippocampus and prefrontal cortex (PFC), key cognitive map regions. We uncovered predictive representations with multi-scale horizons in prefrontal and hippocampal gradients, with the longest predictive horizons in anterior PFC, and the shortest in posterior hippocampus. These findings provide empirical support for the computational hypothesis that multiscale neural representations guide goal-directed navigation. This advances our understanding of hierarchical planning in everyday navigation of realistic distances.
Maximum principle preserving finite difference scheme for 1-D nonlocal-to-local diffusion problems

Abstract In a recent paper (Du et al., 2018), a quasi-nonlocal coupling method was introduced to seamlessly bridge a nonlocal diffusion model with the classical local diffusion counterpart in a one-dimensional space. The proposed coupling framework removes interfacial inconsistency, preserves the balance of fluxes, and satisfies the maximum principle of diffusion problem. However, the numerical scheme proposed in that paper does not maintain all of these properties on a discrete level. In this paper we resolve this issue by proposing a new finite difference scheme that ensures the balance of fluxes and the discrete maximum principle. We rigorously prove these results and provide the stability and convergence analyses accordingly. In addition, we provide the Courant–Friedrichs–Lewy (CFL) condition for the new scheme and test a series of benchmark examples which confirm the theoretical findings.
Phase locking and noise-driven dynamics in a Josephson-junction electronic analog

We present an electronic circuit whose dynamical properties emulate those of a resistively and capacitively shunted Josephson junction (RCSJ). We show how it reproduces the switching properties of a shunted junction and its dependence on the quality factor. A thermal noise source is then used to characterize the temperature dependence of the phase dynamics. In the presence of an AC drive, phase locking is observed at integer and rational multiples of the drive frequency, and it competes with chaotic behavior when the quality factor of the junction exceeds unity. We characterize the stability of phase-locked and chaotic states in the presence of thermal noise.
Malignin, Anti-Malignin Antibody and Scantag

Abstract The antibody to Malignin, a cancer cell 10, 000 Dalton polypeptide of known composition, was quantitatively determined blind by specific immunoadsorption in 1, 094 serum specimens from 1, 026 cancer patients and controls. Anti-malignin antibody, known to be cytotoxic to cancer cells in vitro, was elevated in 92.7% of sera from patients with clinically and pathologically active cancer (mean 273.7 ± 156.7 micrograms/ml) compared with healthy normal subjects (mean 59.1 ± 27.0 micrograms/ml) in a broad range of types of malignancy in support of the hypothesis that Malignin is a general transformation antigen. The antibody was in the normal range (0-134 micrograms/ml) in 100% of sera of healthy normal subjects (first control group), in 94.6% of sera of out-patient hospital non-cancer controls (mean 64.3 ± 46.3 micrograms/ml) (second control group) and in 91.2% of sera of in-patient medical-surgical disorder non-cancer patients (mean 81.2 ± 67.3 micrograms/ml) (third control group). That only an active cancer state appears to be associated with elevated antibody levels is supported by the finding that the antibody was in the normal range in 94.2% of sera from cancer patients who had been successfully treated and clinico-pathologically showed ‘no evidence of disease’ at the time of the determination (fourth control group) (mean 70.1 ± 36.7 micrograms/ml). None of the four control groups was statistically significantly different from the others, but each control group differed from the active cancer group at a level of P in vitro for the selective staining of cancer cells, and in vivo for their localization. Monoclonal Anti-malignin antibodies have now been produced.
The Sacrificial Goat

The Sacrificial Goat It is said he moaned quietly, but did not fight when the knife pierced his breast. Doped by the villagers' dancing, having watched his brother paraded on their shoulders, crowned with fresh flowers, he might have expected similar celebration. The village was like that: a group of them always preparing for some festival. The women scrubbed pots until they shone, then prepared vats of chocolate and cinnamon. The men chopped wood, hammered scaffolding. Even the children, who loved to pat his neck or climb his back before he knocked them off, beheaded dozens of marigolds and strung them into garlands. Had he learned to distinguish the scratch of the sharpening-stone, the smell of oil?but not even the straw mats, laid end to end to hold the slaughtered, or the old women, lined up with their mugs, frightened him. Who
Influence of Seismic History on Liquefaction of Sands

It is shown both analytically and experimentally that deposits of sand subjected to low magnitude earthquakes that are not sufficiently strong to cause liquefaction will develop an increased resistance to liquefaction in subsequent earthquakes even though they may undergo no significant change in density. Accordingly, in order to determine the liquefaction characteristics of a sand it is necessary to perform tests on samples having the same density and structure as the in-situ material and conduct the tests, whenever possible, with the correct in-situ value of K sub 0. The study also indicates that the standard penetration resistance (or any in-situ measure of penetration resistance) is likely to provide a reasonable index of the liquefaction characteristics of a saturated sand deposit. Available data on field performance have been summarized to develop a correlation between penetration resistance and the cyclic stress ratio at which liquefaction has been found to occur in the field. /ASCE/
Building and Positioning Successful Study-Abroad Programs

Abstract The growth in importance of international education is inescapable. The ability to effectively compete in the global environment is linked to many factors -one of which is a knowledge and understanding of the cultures involved. The traditional classroom approach to international business education, while useful, is limited in scope and impact. We approach the issue of international business education from a hands-on, action-oriented immersion approach -the study-abroad program. This paper examines the specifics of developing and implementing such a program, as well as pitfalls to avoid.
Using shade to propagate Canadian wild ginger (Asarum canadense L.) and other woodland forbs

Canadian wild ginger ( Asarum canadense L. [Aristolochiaceae]) is found in a variety of deciduous and moist coniferous forests throughout eastern Canada and the US. Because of the recalcitrant nature of Asarum seeds, we vegetatively propagate this species by divisions under natural shade at the Lake County Forest Preserve nursery in Illinois. This method yields plants suitable for outplanting in 3 y. We also use natural shade under established oak trees for native seed production, and an artificial shade bed system to produce 75 native woodland species found in the midwestern US.
A half century of development

Development as a global policy objective dates from the 1940s. Relative to expectations then, the world economy performed outstandingly well during the second half of the 20th century. One country after another achieved social stability, created the right incentives for effort and risk-taking, and engaged constructively with the world economy, which facilitated economic growth. Those that lagged failed to meet one or more of these conditions. Civil and political liberties also spread during this period, although less certainly and less securely. On the whole, it was a good half century for mankind. The substantial poverty and misery that still exists should not lead to neglect or even denial of these achievements.
Method for calculating risk associated with family history of a disease

A method is described for estimating excess relative risks of a disease from familial factors. Beginning with population-based series of cases and controls, a cohort of each subject's relatives is formed and checked for disease against a population based registry. The disease experience of the cohort formed from each subject's relatives is summarized as a kinship-weighted familial standardized incidence ratio (FSIR). The FSIR's are used as exposure estimates in conditional linear excess relative risk models, which may be used not only to screen for significant familial disease aggregations, but also to estimate relative risks, population attributable risks, and gene-environment interactions. The method is demonstrated on 4083 breast cancer cases from Utah and a set of matched controls.
Management of Renal Arterial Disease

Severe atherosclerotic renal artery stenosis can manifest as treatment-resistant hypertension, ischemic nephropathy and/or cardiac disturbance syndromes of recurrent flash pulmonary edema and refractory angina. Renal artery revascularization can dramatically impact patient outcome. However, patient selection for revascularization can be challenging. Renal artery stenting is most commonly used for renal revascularization and is a safe procedure when performed in carefully selected patients. This review addresses the pathophysiology of renal artery stenosis and the data supporting revascularization in such patients.
Farnesyl Phosphatase, a Corpora allata Enzyme Involved in Juvenile Hormone Biosynthesis in Aedes aegypti

Background The juvenile hormones (JHs) are sesquiterpenoid compounds that play a central role in insect reproduction, development and behavior. The late steps of JH III biosynthesis in the mosquito Aedes aegypti involve the hydrolysis of farnesyl pyrophosphate (FPP) to farnesol (FOL), which is then successively oxidized to farnesal and farnesoic acid, methylated to form methyl farnesoate and finally transformed to JH III by a P450 epoxidase. The only recognized FPP phosphatase (FPPase) expressed in the corpora allata (CA) of an insect was recently described in Drosophila melanogaster (DmFPPase). In the present study we sought to molecularly and biochemically characterize the FPP phosphatase responsible for the transformation of FPP into FOL in the CA of A. aegypti. Methods A search for orthologs of the DmFPPase in Aedes aegypti led to the identification of 3 putative FPPase paralogs expressed in the CA of the mosquito (AaFPPases-1, -2, and -3). The activities of recombinant AaFPPases were tested against general phosphatase substrates and isoprenoid pyrophosphates. Using a newly developed assay utilizing fluorescent tags, we analyzed AaFPPase activities in CA of sugar and blood-fed females. Double-stranded RNA (dsRNA) was used to evaluate the effect of reduction of AaFPPase mRNAs on JH biosynthesis. Conclusions AaFPPase-1 and AaFPPase-2 are members of the NagD family of the Class IIA C2 cap-containing haloalkanoic acid dehalogenase (HAD) super family and efficiently hydrolyzed FPP into FOL. AaFPPase activities were different in CA of sugar and blood-fed females. Injection of dsRNAs resulted in a significant reduction of AaFPPase-1 and AaFPPase-2 mRNAs, but only reduction of AaFPPase-1 caused a significant decrease of JH biosynthesis. These results suggest that AaFPPase-1 is predominantly involved in the catalysis of FPP into FOL in the CA of A. aegypti.
Positron Production and PET Scanning

A new program to study anatomical and physiological aspects of the brain that use positron emission tomographic (PET) techniques was instituted at the University of Michigan. A complete laboratory was constructed to facilitate the production of radiotracers, their incorporation into viable radiopharmaceuticals and the detection of their regional localization. The Cyclotron Corporation (TCC) CS-30 compact cyclotron is used to provide various short-lived s + nuclides. Targets for C-11, N-13, O-15 and F-18 are accomodated on three external beam lines. Steady-state production of several simple physiological tracers are possible and include 15O2, H215O, C15O, 11CO, C15O2 and 11CO2. These gases are purified and available to the chemist in the laboratory or may be diverted to the clinical imaging area for direct inhalation. A F-18 labeled compound, 2-deoxy-2-fluoro-D-glucose (2FDG), is used for determining the level of brain metabolic activity and requires long irradiation/synthesis times. The incorporation of 18F2 into 2FDG is an involved process and has been automated to reduce radiation exposure to the chemist and enhance overall yields. Once the purity of the radiopharmaceuticals is verified it is then injected or inhaled by the patient. The TCC 4600A Neuro Positron Camera Tomograph is used to obtain transaxial images of the brain derived from the annihilation photons of the s+ tracers. The scanner resolution is 1.0 cm by 1.0 cm within the slice and 1.0 cm between slices. The tomograph is capable of simultaneously acquiring 5 slices in 5 seconds at the maximum spatial resolution.
Early Outcome Comparison Between the Direct Anterior Approach and the Mini-Incision Posterior Approach for Primary Total Hip Arthroplasty: 150 Consecutive Cases

This study evaluated early postoperative results of 150 consecutive primary total hip arthroplasties performed by a single surgeon; 50 from mini-incision posterior approach, 50 during the learning curve for the direct anterior approach, and 50 subsequent cases when the approach was routine. The anterior approach groups had significantly reduced hospital length of stays (2.9 and 2.7 days versus 3.9 days for the posterior group; P < 0.0001) and discharge to home versus rehab was more likely (80% and 84% in anterior groups, 56% in posterior group; P = 0.0028). In the anterior groups, there was significantly less use of assistive devices and narcotics at 6 weeks, and pain was significantly lower. Primary total hip arthroplasty using the anterior approach allows for superior recovery in a matched cohort of patients.
Cutaneous larva migrans infection in the pediatric foot. A review and two case reports

Cutaneous larva migrans is the result of infestation of human skin by helminth larvae, which burrow through the epidermis. This route of infestation makes the foot a typical site for origination of this infection. Children, who frequently play barefoot in locations where the most common of the helminth larvae, the dog and cat hookworms, are endemic, are at particular risk for this disorder. This article reviews the differential diagnosis of cutaneous larva migrans and current concepts in management. Two cases of related children who presented to their pediatricians with this condition are reported.
Benthos of adjacent mangrove, seagrass and non-vegetated habitats in Rookery Bay, Florida, U.S.A.

Abstract Benthic faunal abundances and biomasses in adjacent mangrove, seagrass and non-vegetated mud habitats were compared in Rookery Bay, Florida, U.S.A. Although all habitats were intertidal, mangroves received the shortest duration of flooding, and non-vegetated mud received the longest. Replicate cores were taken at high tide in each habitat in July, September and December 1988, and in April 1989. Seagrass substrates were low organic content sands, whereas mangrove and non-vegetated substrates were high organic content sandy clays. Over 300 taxa were recorded, most of them relatively rare, and only 32 taxa were considered dominant (averaging ≥636 individuals m−2or five core−1in any habitat at a given time). Seagrass and non-vegetated mud faunas were more diverse than those of mangrove substrates. Total densities were always higher in red mangrove (Rhizophora mangle) peat than elsewhere, averaging 22 591 to 52 914 individuals m−2. Densities in mixed seagrasses ranged between 6347 and 23 545 individuals m−2, while those in non-vegetated mud ranged between 3611 and 22 465 individuals m−2. Biomasses, however, were always higher in either seagrasses (15·7–87·4 g wet weight m−2) or non-vegetated mud (11·9–26·2 g m−2) than in mangroves (3·6–8·2 g m−2). Tanaids and annelids were the numerical dominants, reaching maximum densities of 35 127 and 31 388 m−2, respectively, in mangroves. Annelids were also the dominant biomass in most habitats each month. Variation in densities of most of the 32 dominant taxa were related to habitat not time. Each habitat harboured four to eight taxa that were significantly more abundant there than in alternate habitats. Feeding guild analysis indicated few differences among habitats, as surface deposit feeders and carnivores were predominant. Red mangrove appear capable of functioning in a manner similar to intertidal marsh habitats by providing high densities of small prey items for mobile consumers able to exploit the intertidal zone during high tide. Experimental verification of this function remains necessary.
Formal Specification of User Interfaces: A Comparison and Evaluation of Four Axiomatic Approaches

Few examples of formal specification of the semantics of user interfaces exist in the literature. This paper presents a comparison of four axiomatic approaches which we have applied to the specification of a commercial user interface–the line editor for the Tandy PC-1 Pocket Computer. These techniques are shown to result in complete and relatively concise descriptions. A number of useful and nontrivial properties of the interface are formally deduced from one of the specifications. In addition, a direct implementation of the interface is constructed from a formal specification. Limitations of these specification examples are discussed along with future research work.
Doubly differential cross sections of secondary electrons ejected from atomic hydrogen by electron impact.

We have measured the doubly differential cross sections, in angle and energy, of secondary electrons ejected from atomic hydrogen by electron impact. The incident energies used were from 25 to 250 eV. The energy and angular range of secondary electrons measured were from 1.0 eV to one-half of the difference between the incident energy and the ionization potential of hydrogen atom and from 12{degree} to 156{degree}, respectively. Singly differential cross sections and total-ionization cross sections were obtained from the doubly differential cross sections. The present total-ionization cross sections were compared with previous measurements and theoretical results. Discrepancies have been found between the present results and those measurements and theoretical results.
The effects of propranolol on cholesterol-induced atheromatous lesions.

Abstract The effects of propranolol on cholesterol-induced atheromatous lesions in rabbits and on the calcium content of the vascular tissue of these animals were studied. The calcium content of normal rabbit aortae was significantly lower than that of the aortae of rabbits receiving a 2% cholesterol supplemented diet. The calcium content from rabbit aortae which had received a 2% by weight cholesterol diet was significantly higher than that of the aortae of rabbits which received propranolol plus cholesterol, and of the aortae of rabbits which received a normal diet plus propranolol. Histological results showed atheromatous plaques within the intimal layer of the aortae of the cholesterol group. Some of the rabbits which received propranolol plus cholesterol had lesions, but these were less severe than those of the cholesterol group. These results indicate that propranolol affects fat and calcium metabolism in the aorta.
Sensitivity of specific immune function tests to acute nutrient deprivation as indicators of nutritional status in a feline model

The sensitivity of monocyte phagocytic activity, major histocompatibility complex (MHC) class II expression, and fibronectin concentration were studied in 23 healthy cats during a 7-day fast followed by a 7-day refeeding period. Immune cell function tests, and body weight were determined on days 0, 4, 7, 11, and 14. Phagocytic activity, weight, lymphocyte number, white blood cell (WBC) number, MHC class II expression, and percent lymphocytes decreased (p<0.05) during the starvation period. Fibronectin concentration increased (p<0.05) by day 4 of starvation then decreased by day 7. During refeeding there was an increase (p<0.05) in MHC class II, fibronectin, weight, lymphocyte number, percent lymphocytes, and WBC number when compared to day 7. Macrophage phagocytic activity decreased (p<0.05) on day 11, followed by an increase on day 14. There was a positive correlation (p<0.05, r=0.3588) between monocyte number and MHC class II expression, and monocyte number and WBC number (p<0.05, r=0.3506). There was a positive correlation (p<0.05, r=0.2682) between weight change and phagocytic activity. In conclusion, MHC class II expression and phagocytosis were found to be reliable indicators of nutritional status during acute nutritional deprivation; however, fibronectin was not found to be a reliable indicator of nutritional status as it lacked consistency in its response to nutritional depletion and repletion.
A comparative study of some rank tests for interaction

Abstract Statistical methods based on ranking after alignment are known to be versatile and powerful techniques. Although the theoretical properties of these methods are well-known, no empirical results are available on these procedures. Two versions of the F -statistic analogue of the aligned rank method for interaction in two-way layouts are studied along with the classical F -test and the rank transform test that has been the focus of several studies in recent years. Based on extensive simulation studies we conclude that the aligned rank tests should generally be preferred in application. We further show that none of these tests performs well for the Cauchy distribution. We show that the problem with inflation in the Type I error rate of the rank transform statistic (Blair et al., 1987), can be overcome by the use of the normal scores.
Trust in People Among Hispanic Americans

There is a dearth of reliable information about the attitudes of the largest minority, Hispanic Americans. The attitudes that were reliably examined were practically identical to the larger population of non-Hispanic Whites, at least for those who speak English very well. This study of English-speaking Hispanic Americans (n=971) and non-Hispanic White respondents (n=16,202) to 18 recent nationwide public-opinion surveys produced an anomalous result. On a generalized attitude toward human nature widely used to reflect trust in people, misanthropy, and social capital, Hispanic Americans of both sexes were significantly less likely to say they believe people can be trusted, try to be fair, and try to be helpful. These significant differences existed across many control variables. Doubt was cast on the possibility that the differences were explained by economic status, feelings of being discriminated against, or acculturation.
Consistent Parametric Estimation of the Intensity of a Spatial-temporal Point Process

Abstract We consider conditions under which parametric estimates of the intensity of a spatial–temporal point process are consistent. Although the actual point process being estimated may not be Poisson, an estimate involving maximizing a function that corresponds exactly to the log-likelihood if the process is Poisson is consistent under certain simple conditions. A second estimate based on weighted least squares is also shown to be consistent under quite similar assumptions. The conditions for consistency are simple and easily verified, and examples are provided to illustrate the extent to which consistent estimation may be achieved. An important special case is when the point processes being estimated are in fact Poisson, though other important examples are explored as well.
The effect of hydrogen passivation on Si nanocrystals: Surface and spin states

Abstract In this paper hybrid density functional theory has been used to study the electronic properties of silicon nanocrystals (SiNCs) having 75, 150 and 300 silicon atoms with and without hydrogen passivation. Wurtzite structure has been found to be more stable than the diamond structure irrespective of the passivation at the sizes considered here. In addition to the HOMO–LUMO gap broadening, the hydrogen passivation was found to affect the orbital distribution of the passivated SiNC. It has been also found that, the stability of the higher spin-state structures, even with hydrogen passivation, are very close to the lowest energy singlet structure and have very small gaps at these size levels.
Horizontal Gene Transfer on Surfaces in Natural Porous Media: Conjugation and Kinetics

The transfer of genetic material among bacteria in the environment has been linked to a range of important phenomena related to bacterial adaptation and evolution, including bioremediation capability, metal tolerance, antibiotic resistance by pathogens in the environment, and gene flow from genetically modified microorganisms. Transfer of genetic material can occur among microorganisms present in both the planktonic and attached states. Given the propensity of organisms to exist in sessile communities under oligotrophic conditions, and that such conditions typify the subsurface, study of subsurface gene transfer phenomena should include processes and kinetics for a range of sessile community structures, from reversibly attached single cells to mature biofilms, as well as planktonic communities. This study very briefly reviewed horizontal, primarily conjugative, gene transfer in natural porous media, and the kinetics used to date to describe conjugative gene transfer in both planktonic (aqueous suspension) and sessile (surface associated) communities. The mathematics so far used to describe the kinetics of conjugation have developed largely from experimental observations of planktonic gene transfer, and are absent of time lags that occur between gene transfer events or plasmid stability that appear experimentally. We develop a novel formulation of delay-difference equations for gene transfer for attached-state microbes using an exposure-time approach to account for lags.
Roles for CCN2 in normal physiological processes

CCN2, also known as connective tissue growth factor, is a member of the CCN (CCN1-6) family of modular matricellular proteins. Analysis of CCN2 function in vivo has focused primarily on its key role as a mediator of excess ECM synthesis in multiple fibrotic diseases. However, CCN2 and related family members are widely expressed during development. Recent studies using new genetic models are revealing that CCN2 has essential roles in the development of many tissues. This review focuses on current and emerging data on CCN2 and its functions in chondrogenesis and angiogenesis, and on new studies showing that CCN2 has essential functions during embryonic and postnatal development in a number of epithelial tissues.