cssi/SciSciGPT-SciSciNet huggingface dataset:
Literacy traps: Society‐wide education and individual skill premia

Using a model of an O-ring production function, the present paper demonstrates how certain communities can get caught in a low-literacy trap in which each individual finds that it is not worthwhile investing in higher skills because others are not high-skilled. The model sheds light on educational policy. It is shown that policy for promoting human capital has to take the form of a mechanism for solving the coordination failure in people's choice of educational strategy.
Real-time decision aiding: aircraft guidance for wind shear avoidance

Modern estimation theory and artificial intelligence technology are applied to the Wind Shear Safety Advisor, a conceptual airborne advisory system to help flight crews avoid or survive encounter with hazardous low-altitude wind shear. Numerical and symbolic processes of the system fuse diverse, time-varying data from ground-based and airborne measurements. Simulated wind-shear-encounter scenarios illustrate the need to consider a variety of factors for optimal decision reliability. The wind-shear-encounter simulations show the potential of the Wind Shear Safety Advisor for effectively integrating the available information, highlighting the benefits of the computational techniques employed. >
Enantioselective Imidazole-Directed Allylation of Aldimines and Ketimines

A new chiral allylchlorosilane has been developed that allows the highly enantioselective allylation and crotylation of a range of 2-imidazolylaldimines and ketimines. The method may be exploited for the protecting group-free synthesis of a diverse array of imidazole-bearing chiral carbinamines and, when coupled with ring-closing metathesis reactions, allows the one-pot synthesis of unusual heterocyclic motifs with potential relevance in medicinal chemistry.
Subband coding for large-scale scientific simulation data using JPEG 2000

The ISO/IEC JPEG 2000 image coding standard is a family of source coding algorithms targeting high-resolution image communications. JPEG 2000 features highly scalable embedded coding features that allow one to interactively zoom out to reduced resolution thumbnails of enormous data sets or to zoom in on highly localized regions of interest with very economical communications and rendering requirements. While intended for fixed-precision input data, the implementation of the irreversible version of the standard is often done internally in floating point arithmetic. Moreover, the standard is designed to support high-bit-depth data. Part 2 of the standard also provides support for three-dimensional data sets such as multicomponent or volumetric imagery. These features make JPEG 2000 an appealing candidate for highly scalable communications coding and visualization of two- and three-dimensional data produced by scientific simulation software. We present results of initial experiments applying JPEG 2000 to scientific simulation data produced by the Parallel Ocean Program (POP) global ocean circulation model, highlighting both the promise and the many challenges this approach holds for scientific visualization applications.
Logarithmic Quantile Estimation for Rank Statistics

We prove an almost sure weak limit theorem for simple linear rank statistics for samples with continuous distributions functions. As a corollary, the result extends to samples with ties and to the vector version of an almost sure (a.s.) central limit theorem for vectors of linear rank statistics. Moreover, we derive such a weak convergence result for some quadratic forms. These results are then applied to quantile estimation, and to hypothesis testing for nonparametric statistical designs, here demonstrated by the c-sample problem, where the samples may be dependent. In general, the method is known to be comparable to the bootstrap and other nonparametric methods (Thangavelu 2005; Fridline 2009), and we confirm this finding for the c-sample problem.
Performance bounds for coprime factor controller reductions

This paper investigates the performance of coprime factor based controller reduction methods. We show that under some mild conditions closed-loop performance bounds can be derived for observer-based controllers. The results in this paper lay a mathematical foundation for using coprime factor controller reduction methods in certain classes of controller reduction problems.
Parents’ Preferences for Enhanced Access in the Pediatric Medical Home: A Discrete Choice Experiment

Importance Efforts to transform primary care through the medical home model may have limited effectiveness if they do not incorporate families’ preferences for different primary care services. Objective To assess parents' relative preferences for different categories of enhanced access services in primary care. Design, Setting, and Participants Internet-based survey that took place with a national online panel from December 8, 2011, to December 22, 2011. Participants included 820 parents of children aged 0 to 17 years. Hispanic and black non-Hispanic parents were each oversampled to 20% of the sample. The survey included a discrete choice experiment with questions that asked parents to choose between hypothetical primary care practices with different levels of enhanced access and other primary care services. Main Outcomes and Measures We estimated parents’ relative preferences for different enhanced access services using travel time to the practice as a trade-off and parents’ marginal willingness to travel in minutes for practices with different levels of services. Results The response rate of parents who participated in the study was 41.2%. Parents were most likely to choose primary care offices that guaranteed same-day sick visits (coefficient, 0.57 [SE, 0.05]; P P P P Conclusions and Relevance As primary care practices for children implement aspects of the medical home model, those that emphasize same-day sick care and professional continuity are more likely to meet parents’ preferences for enhanced access. Practices should seek to engage families in prioritizing changes in practice services as part of medical home implementation.
The Warm, Cold and Very Cold Dusty Universe

We are living in a dusty universe: dust is ubiquitously seen in a wide variety of astrophysical environments, ranging from circumstellar envelopes around cool red giants to supernova ejecta, from diffuse and dense interstellar clouds and star-forming regions to debris disks around main-sequence stars, from comets to interplanetary space to distant galaxies and quasars.
Emerging Technology in Head and Neck Ultrasonography

Increased use of ultrasonography of the head and neck by clinicians has resulted from more compact, higher resolution ultrasound machines that can be more readily used in the office setting. Palm-sized machines are already used for vascular access and bladder assessment. As the resolution of these machines becomes adequate for head and neck assessment, ultrasonography is likely to become a routine adjunct to the office physical examination. Further techniques to reduce artifact beyond spatial compounding, second harmonics, and broadband inversion techniques are likely to be developed to improve ultrasound images. Manual palpation using the ultrasound transducer or "sound palpation," using sound to recreate vibration provides information on tissue "stiffness," which has been successfully used to distinguish between benign and malignant lesions in the head and neck (particularly thyroid nodules). Microbubble contrast-enhanced ultrasound provides improved resolution of ultrasound images. Three- and four-dimensional ultrasonography provides for more accurate diagnosis. The ability of microbubbles with ligands affixed to their outer surface to target specific tissue makes them excellent delivery vehicles. DNA plasmids, chemotherapy agents, and therapeutic drugs can be released at a specific anatomic site. The motion of microbubbles stimulated by ultrasound can be used to increase drug penetration through tissues and has been shown to be effective in breaking up clots in stroke patients (without increased risk). High-intensity focused ultrasound can be used to create coagulation necrosis without significant damage to adjacent tissue. It has been effectively used in neurosurgery and urology, but its effectiveness in the head and neck is still being determined. A prototype for surgical navigation with ultrasound has been developed for the head and neck, which allows real-time imaging of anatomic surgical changes.
The Second Order Upper Bound for the Ground Energy of a Bose Gas

Consider N bosons in a finite box Λ=[0,L]3⊂R3 interacting via a two-body smooth repulsive short range potential. We construct a variational state which gives the following upper bound on the ground state energy per particle $$\overline{\lim}_{\rho\to0}\overline{\lim}_{L\to\infty,\,N/L^3\to \rho}\biggl(\frac{e_0(\rho)-4\pi a\rho}{(4\pi a)^{5/2}(\rho)^{3/2}}\biggr )\leq\frac{16}{15\pi^2},$$ where a is the scattering length of the potential. Previously, an upper bound of the form C16/15π2 for some constant C>1 was obtained in (Erdos et al. in Phys. Rev. A 78:053627, 2008). Our result proves the upper bound of the prediction by Lee and Yang (Phys. Rev. 105(3):1119–1120, 1957) and Lee et al. (Phys. Rev. 106(6):1135–1145, 1957).
The Mexico-China Sourcing Game: Teaching Global Dual Sourcing

We describe a three-hour class on global dual sourcing built around a game that demonstrates the challenges in making operational decisions, and transfers recent academic insights to the classroom. Student teams manage a firm with access to a responsive but expensive supply source Mexico and a cheap but remote source China. Each team must determine a sourcing strategy to satisfy random demand that is revealed throughout the game. In each period, teams place orders to both sources and manage two assets: inventory and their bank account. The goal is to maximize each team's value final bank balance. During the debriefings, we analyze the policies used by different teams along both financial and operational metrics, present the optimal strategy, and summarize the experiential learning points.
Electronic structure of Fe-based superconductors

The electronic structure of the Fe-based superconductors is discussed, mainly from the point of view of first principles calculations in relation to experimental data. Comparisons and contrasts with cuprates are made. The problem of reconciling experiments indicating an s symmetry gap with experiments indicating line nodes is discussed and a possible resolution is given.
The Long-Term Economic Impact of In Utero and Postnatal Exposure to Malaria

This paper examines the long-term economic impact of in utero and postnatal exposure to malaria using historical data from the United States. Recent research shows that individuals who were exposed to early-life health shocks have worse outcomes as adults, all else being equal. Because malaria has an acute impact on in utero and postnatal health conditions, such exposure may have significant economic effects over the life cycle. To test this conjecture, I match adults in the 1960 Decennial Census to the malaria death rate in their state-year of birth. Because malaria death rates are potentially correlated with important omitted variables and measured with error, I employ a novel identification strategy that uses variation in interacted hot and rainy weather conditions to instrument for malaria exposure. The IV estimates indicate that adults exposed to malaria around the time of birth had significantly lower levels of educational attainment.
New technetium-99m generator technologies utilizing polyethylene glycol-based aqueous biphasic systems

Abstract Two new schemes for TcO4 −/MoO4 2− separations from OH− and MoO4 2− media using polyethylene glycol (PEG)-based aqueous biphasic systems (ABS) have been developed. The two most important salt solutions in current 99mTc-generator technologies, OH− and MoO4 2−, also salt out PEG to form ABS. In liquid/liquid PEG-ABS, pertechnetate can be separated from molybdate with separation factors as high as 10,000. Stripping is accomplished by reduction of the TcO4 − and back extraction into a salt solution. The strip solution can be the salt of an imaging agent (e.g., Na4HEDPA) and thus may, under the appropriate conditions, be injected directly into the human body. 99mTcO4 − can also be concentrated from a dilute load solution of 99MoO4 2− in NaOH using an aqueous biphasic extraction chromatographic technique (ABEC). A rinse with K2CO3 assures that all 99MoO4 2− is removed from the column, and this is confirmed by a rapid drop in 99Mo activity by the fourth free column volume (fcv) of rinse. The 99mTcO4 − i...
Interleaver design for high speed turbo decoders

Recently some efficient parallel architectures for turbo decoder have been proposed. In these architectures the bottleneck for the parallelization of the decoder is the interleaver. On the other hand, turbo codes achieve a very impressive near Shannon-capacity performance in which the interleaver plays a crucial role. Therefore, it is of great interest to design interleaves that are good from both performance and parallelization point of views. In this paper we propose an interleaver structure that is very suitable for parallelization of turbo decoders. It is shown that such an interleaver can be designed to have good BER performance as well. By this structure not only fast decoders with very low latency can be built, but also the regularity of the decoder and the simplicity of the interleaver structure make them very promising for VLSI implementation. We also present a fast algorithm to design such an interleaver, which can be used to design S-random interleavers as well. Such interleavers have been designed and the performances are compared to that of S-random interleavers by simulations.
A High-Availability, Distributed Hardware Control System Using Java

Two independent coronagraph experiments that require 24/7 availability with different optical layouts and different motion control requirements are commanded and controlled with the same Java software system executing on many geographically scattered computer systems interconnected via TCP/IP. High availability of a distributed system requires that the computers have a robust communication messaging system making the mix of TCP/IP (a robust transport), and XML (a robust message) a natural choice. XML also adds the configuration flexibility. Java then adds object-oriented paradigms, exception handling, heavily tested libraries, and many third party tools for implementation robustness. The result is a software system that provides users 24/7 access to two diverse experiments with XML files defining the differences.
B-L mediated supersymmetry breaking

Abstract I present a realistic model of dynamical supersymmetry breaking, in which a U (1) B - L gauge interaction communicates supersymmetry breaking to the standard fields. A distinctive superpartner spectrum is predicted in this model.
Healthy convenience: nudging students toward healthier choices in the lunchroom

Background In the context of food, convenience is generally associated with less healthy foods. Given the reality of present-biased preferences, if convenience was associated with healthier foods and less healthy foods were less convenient, people would likely consume healthier foods. This study examines the application of this principle in a school lunchroom where healthier foods were made more convenient relative to less healthy foods. Methods One of two lunch lines in a cafeteria was arranged so as to display only healthier foods and flavored milk. Trained field researchers collected purchase and consumption data before and after the conversion. Mean comparisons were used to identify differences in selection and consumption of healthier foods, less healthy foods and chocolate milk. Results Sales of healthier foods increased by 18% and grams of less healthy foods consumed decreased by nearly 28%. Also, healthier foods’share of total consumption increased from 33 to 36%. Lastly, we find that students increased their consumption of flavored milk, but flavored milk’s share of total consumption did not increase.
On the Conformal Field Theory of the Higgs Branch

We study 1+1-dimensional theories of vector and hypermultiplets with (4,4) supersymmetry. Despite strong infrared fluctuations, these theories flow in general to distinct conformal field theories on the Coulomb and Higgs branches. In some cases there may be a quantum Higgs theory even when there is no classical Higgs branch. The Higgs branches of certain such theories provide a framework for a matrix model of Type IIA fivebranes and the associated exotic six-dimensional string theories. Proposals concerning the interactions of these string theories are evaluated.
Changes in local energy spectra with SPECT rotation for two Anger cameras

We investigated the shift of local energy spectra with SPECT rotation for the GE 400 AT and the Picker Prism 3006 tomographs. A Co-57 flood source was taped to the parallel-beam collimator of the GE 400 AT; a Tc-99m line source was placed at the focus of the fan-beam collimator of one head of the Picker Prism. The count-based method, which employs a narrow window (about 4 keV) on the maximum slope of the photopeak, was used with both systems. Non-linear, polynomial spectral fitting was applied to x-y-E data acquisitions with the GE camera. The fitting yielded either shifts or shifts and width changes. Results show: 1) the shifts are pseudo-sinusoidal with angle and similar for different spatial locations, 2) the average of their absolute value is 0.71 keV and 0.13 keV for the GE and Picker cameras, respectively, 3) width changes for the GE camera are small and appear random, 4) the calculated shifts from the count-based method for the central part of the GE camera are correlated with those from the spectral fitting method. They are 12% smaller. The conclusion is that energy shifts with angle may be present with many rotating cameras although they may be smaller with newer cameras. It might be necessary to account for them in schemes designed for high-accuracy compensation of Compton-scattered gamma rays although they possibly could be ignored for newer cameras. >
The Economics of Desecration: Flag Burning and Related Activities

Abstract When a symbol is desecrated, the desecrator obtains benefits while other people incur costs. Negative externalities are intrinsic to desecration, suggesting a case for government regulation if the costs exceed the benefits. The case for restrictions is especially strong because of the impracticality of Coasean bargaining and the possibility of efficient lawbreaking. In addition, desecration reduces the incentive for the creation and maintenance of symbols, which, like other goods, need property‐rights protection for efficient production.
Novel extension of MSSM and “TeV scale” coupling unification

Abstract Motivated by the coupling unification problem, we propose a novel extension of the Minimal Supersymmetric Standard Model. One of the predictions of this extension is the existence of new states neutral under SU (3) c ⊗ SU (2) w but charged under U (1) y . The mass scale for these new states can be around the mass scale of the electroweak Higgs doublets. This suggests the possibility of their detection in the present or near future collider experiments. Unification of gauge couplings in this extension is as precise (at one loop) as in the MSSM, and can occur in the TeV range.
A novel desymmetrization reaction of an acetogenin precursor: A formal synthesis of trilobacin and asimicin

Abstract A two-directional strategy which is based on the haloetherification reaction of a bis-5,6-O-isopropylidene alkene, is applied to the synthesis of a versatile relay compound for the bis-THF containing acetogenins.
Hyperspectral texture classification using generalized Markov fields

We present a generalized random field model in a random environment to classify hyperspectral textures. The model generalizes traditional random field models by allowing the spatial interaction parameters of the field to be random variables. Principal component analysis is used to reduce the dimensionality of the data set to a small number of spectral bands that capture almost all of the energy in the original hyperspectral textures. Using the model we obtain a compact feature vector that efficiently computes within- and between-band information. Using a set of hyperspectral samples, we evaluate the performance of this model for classifying textures and compare the results with other approaches that consider different kinds of spatial, spectral, and intensity distribution information.
Fedora: an architecture for complex objects and their relationships

The Fedora architecture is an extensible framework for the storage, management, and dissemination of complex objects and the relationships among them. Fedora accommodates the aggregation of local and distributed content into digital objects and the association of services with objects. This allows an object to have several accessible representations, some of them dynamically produced. The architecture includes a generic Resource Description Framework (RDF)-based relationship model that represents relationships among objects and their components. Queries against these relationships are supported by an RDF triple store. The architecture is implemented as a web service, with all aspects of the complex object architecture and related management functions exposed through REST and SOAP interfaces. The implementation is available as open-source software, providing the foundation for a variety of end-user applications for digital libraries, archives, institutional repositories, and learning object systems.
CMS: Present Status, Limitations, and Upgrade Plans

Abstract An overview of the CMS upgrade plans will be presented. A brief status of the CMS detector will be given, covering some of the issues we have so far experienced. This will be followed by an overview of the various CMS upgrades planned, covering the main motivations for them, and the various R&D efforts for the possibilities under study.
Sources of ethical conflict in medical housestaff training: a qualitative study.

Abstract Purpose Despite increased emphasis on medical ethics and professionalism in medical education, concern about unethical and unprofessional behavior by physicians is widespread. This study sought to identify and classify the range of work-related ethical conflicts experienced by medical house officers. Methods We performed a qualitative study using data from in-depth interviews conducted in 2001 with 31 internal medicine residents in one traditional and one primary care residency. Using the constant comparative method, we explored work-related experiences during housestaff training that involved ethical conflict with patients or colleagues. Results The interviews revealed five categories of ethical conflict: concern over telling the truth, respecting patients' wishes, preventing harm, managing the limits of one's competence, and addressing performance of others that is perceived to be inappropriate. Conflicts occurred between residents and attending physicians, patients or families, and other residents. Many of the conflicts were exacerbated by the function of the hierarchical structure in residency training. Conclusions This study provides a classification of work-related ethical conflicts that houseofficers experience, which may be used to improve the working environment for residents and support their professional development. By attending to the challenges that residents face, particularly previously underemphasized conflicts concerning competence and performance, this framework can be used to enhance education in ethics and professionalism.
Segregation of molecules at cell division reveals native protein localization

We introduce a nonintrusive method exploiting single-cell variability after cell division to validate protein localization. We found that Clp proteases, widely reported to form biologically relevant foci, were uniformly distributed in Escherichia coli cells, and that many commonly used fluorescent proteins caused severe mislocalization when fused to homo-oligomers. Retagging five other reportedly foci-forming proteins with the most monomeric fluorescent protein tested suggests that the foci were caused by the fluorescent tags.
The Ages of Stars

The age of an individual star cannot be measured, only estimated through mostly model-dependent or empirical methods, and no single method works well for a broad range of stellar types or for a full range in age. This review presents a summary of the available techniques for age-dating stars and ensembles of stars, their realms of applicability, and their strengths and weaknesses. My emphasis is on low-mass stars because they are present from all epochs of star formation in the Galaxy and because they present both special opportunities and problems. The ages of open clusters are important for understanding the limitations of stellar models and for calibrating empirical age indicators. For individual stars, a hierarchy of quality for the available age-dating methods is described. Although our present ability to determine the ages of even the nearest stars is mediocre, the next few years hold great promise as asteroseismology probes beyond stellar surfaces and starts to provide precise interior properties o...
SIMULATIONS OF MAGNETOROTATIONAL TURBULENCE WITH A HIGHER-ORDER GODUNOV SCHEME

We apply a new, second-order Godunov code, Athena, to studies of the magnetorotational instability (MRI) using unstratified shearing box simulations with a uniform net vertical field and a sinusoidally varying zero net vertical field. The Athena results agree well with similar studies that used different numerical algorithms, including the observation that the turbulent energy decreases with increasing resolution in the zero net field model. We conduct analyses to study the flow of energy from differential rotation to turbulent fluctuations to thermalization. A study of the time correlation between the rates of change of different volume-averaged energy components shows that energy injected into turbulent fluctuations dissipates on a timescale of Ω–1, where Ω is the orbital frequency of the local domain. Magnetic dissipation dominates over kinetic dissipation, although not by as great a factor as the ratio of magnetic to kinetic energy. We Fourier-transform the magnetic and kinetic energy evolution equations and, using the assumption that the time-averaged energies are constant, determine the level of numerical dissipation as a function of length scale and resolution. By modeling numerical dissipation as if it were physical in origin, we characterize numerical resistivity and viscosity in terms of effective Reynolds and Prandtl numbers. The resulting effective magnetic Prandtl number is ~2, independent of resolution or initial field geometry. MRI simulations with effective Reynolds and Prandtl numbers determined by numerical dissipation are not equivalent to those where these numbers are set by physical resistivity and viscosity. These results serve, then, as a baseline for future shearing box studies where dissipation is controlled by the inclusion of explicit viscosity and resistivity.
Development of a decarboxylative palladation reaction and its use in a Heck-type olefination of arene carboxylates.

The development of a palladium-catalyzed decarboxylative coupling reaction of arene carboxylates with olefinic substrates is described. The optimized procedure for decarboxylative palladation employs Pd(O2CCF3)2 as catalyst (0.2 equiv) in the presence of Ag2CO3 (3 equiv) in the solvent 5% DMSO-DMF and proceeds at temperatures of 80−120 °C with a wide range of arene carboxylates and alkenes as substrates. The process is proposed to proceed by an initial Ar-SE reaction involving ipso attack of an electrophilic Pd(II) intermediate on an arene carboxylate to form an arylpalladium(II) species with loss of carbon dioxide. This intermediate is then proposed to react with an olefinic substrate by steps common to the Heck coupling process. Reoxidation of the liberated Pd(0) in situ is proposed to establish the catalytic cycle.
Extended Linial Hyperplane Arrangements for Root Systems and a Conjecture of Postnikov and Stanley

A hyperplane arrangement is said to satisfy the “Riemann hypothesis” if all roots of its characteristic polynomial have the same real part. This property was conjectured by Postnikov and Stanley for certain families of arrangements which are defined for any irreducible root system and was proved for the root system A_n − 1. The proof is based on an explicit formula [1, 2, 11] for the characteristic polynomial, which is of independent combinatorial significance. Here our previous derivation of this formula is simplified and extended to similar formulae for all but the exceptional root systems. The conjecture follows in these cases.
Broadly-tunable resonant-cavity light-emitting diode

Microelectromechanical wavelength tuning is demonstrated for the first time in a resonant-cavity light-emitting diode. The device utilizes a deformable-membrane top mirror suspended by an air gap above a diode-active region and bottom mirror. Applied membrane-substrate bias produces an electrostatic force which reduces the air-gap thickness, and therefore, the resonant wavelength. We report broad tunability of nearly 40 nm and spectral linewidths as narrow as 1.9 nm (2.6 meV) for operation near 950 nm. >
Structure–activity relationships in supported Au catalysts

Au-based catalysts have great potential because of their unique activity and selectivity for a variety of important reactions. The special catalytic properties of supported Au nano-particles depend critically upon the particle morphology, i.e. size, shape and thickness, as well as support effects. This paper reviews the current understanding of CO oxidation on supported Au catalysts. The electronic structure of Au particles at various nucleation sites and on different supports is summarized, and the effect these changes have on catalytic performance is discussed. Recent results from our laboratories have demonstrated the synthesis of well-ordered Au mono- and bi-layer films on a titanium oxide support and show that the active Au structure for CO oxidation is an electron-rich, Au bi-layer. In contrast, the monolayer structure, which may involve the TiOx support, is significantly less active (by less than an order of magnitude) than the Au bi-layer. The oxidation state of the Au and how this relates to the catalytic activity are also discussed. # 2005 Elsevier B.V. All rights reserved.
Exploring three-dimensional higher-spin supergravity based on sl(N|N − 1) Chern-Simons theories

We investigate various aspects of higher-spin anti-de Sitter supergravity in three dimensions as described by Chern-Simons theory based on the finite-dimensional superalgebra sl(N|N − 1), with the particular case of N = 3 as our prime example. This class of theories serves as a natural supersymmetrization of the higher-spin gravity theory based on sl(N) Chern-Simons theories. We demonstrate explicitly that the asymptotic symmetry algebra contains the $ \mathcal{N}=2 $ superconformal algebra in each sector. The appropriate Killing spinor equations are derived and used to classify existing and new classical solutions. We also discuss holonomy conditions, higher-spin black holes and conical defect spacetimes in this class of theories.
Expansion of hydrogen arcs driven by oscillating currents

Calculations of the arc channel radius using the arc current as the independent variable are presented and discussed. Previously reported experimental results for the expansion of approximately 300-A to approximately 3000-A discharges in 460-torr hydrogen are compared with the theoretical radius calculations presented. Errors introduced in the calculated channel radius are investigated by first assuming the channel conductivity to vary according to the Spitzer conductivity, and then assuming the channel conductivity to be constant and comparing the numerical results of these two methods with the experimentally measured values of channel radius. It is shown that according to Hugoniot adiabatics, the apparent relationship between the arc channel pressure and the directed energy of the shock front is given by the pressure-velocity relationship of the gas leaving the shock front instead of the more commonly used pressure-velocity relationship for the gas entering the shock front. >
Disruption of Kif3a in osteoblasts results in defective bone formation and osteopenia

We investigated whether Kif3a in osteoblasts has a direct role in regulating postnatal bone formation. We conditionally deleted Kif3a in osteoblasts by crossing osteocalcin (Oc; also known as Bglap)-Cre with Kif3a(flox/null) mice. Conditional Kif3a-null mice (Kif3a(Oc-cKO)) had a 75% reduction in Kif3a transcripts in bone and osteoblasts. Conditional deletion of Kif3a resulted in the reduction of primary cilia number by 51% and length by 27% in osteoblasts. Kif3a(Oc-cKO) mice developed osteopenia by 6 weeks of age unlike Kif3a(flox/+) control mice, as evidenced by reductions in femoral bone mineral density (22%), trabecular bone volume (42%) and cortical thickness (17%). By contrast, Oc-Cre;Kif3a(flox/+) and Kif3a(flox/null) heterozygous mice exhibited no skeletal abnormalities. Loss of bone mass in Kif3a(Oc-cKO) mice was associated with impaired osteoblast function in vivo, as reflected by a 54% reduction in mineral apposition rate and decreased expression of Runx2, osterix (also known as Sp7 transcription factor 7; Sp7), osteocalcin and Dmp1 compared with controls. Immortalized osteoblasts from Kif3a(Oc-cKO) mice exhibited increased cell proliferation, impaired osteoblastic differentiation, and enhanced adipogenesis in vitro. Osteoblasts derived from Kif3a(Oc-cKO) mice also had lower basal cytosolic calcium levels and impaired intracellular calcium responses to fluid flow shear stress. Sonic hedgehog-mediated Gli2 expression and Wnt3a-mediated β-catenin and Axin2 expression were also attenuated in Kif3a(Oc-cKO) bone and osteoblast cultures. These data indicate that selective deletion of Kif3a in osteoblasts disrupts primary cilia formation and/or function and impairs osteoblast-mediated bone formation through multiple pathways including intracellular calcium, hedgehog and Wnt signaling.
Scope and Scale Economies for Multi-Product Farms: Firm-Level Panel Data Analysis

This study used the flexible fixed cost quadratic function to analyze the cost structure of multi- product farms using farm-level panel data. The robustness of estimated parameters are examined using four panel data estimators. Results suggest that scale economies remain significant in Illinois farming. An increase in soybean acreage reduces the marginal cost of producing corn. Firm-specific effects, that indicate the levels of fixed costs, are found to be positive and significant.
Endostitch-assisted endoscopic Zenker's diverticulostomy: a tried approach for difficult cases.

SUMMARY The aim was to describe a tried approach to endoscopic Zenker's diverticulostomy, especially in those patients with unfavorable anatomy or smaller pouches who may otherwise be relegated to open repair. The study design was a retrospective case series The setting was an urban, tertiary care university medical center There were seven patients, both inpatient and outpatient, with chief complaints of dysphagia. All had a documented Zenker's diverticulum (ZD) on barium swallow. All of the patients were deemed by the primary surgeon to have some anatomic factor that limited exposure of the diverticulum. The patients underwent Endostitch-assisted endoscopic Zenker's diverticulostomy. Records were retrospectively reviewed, including preoperative and postoperative swallowing status, radiographic findings, operative findings, and follow-up results. Seven patients were reviewed, each of whom had successful endoscopic treatment of ZD. Notably, in each case, an anatomical factor precluded the seating of the gastrointestinal anastomosis (GIA) stapler on the cricopharyngeal bar without the use of endoscopic retention sutures. The majority of the patients were discharged on postoperative day one. All but one patient noted a marked improvement in swallowing function immediately following the procedure and at their outpatient follow-up visit. Endoscopic Zenker's diverticulostomy has been well-described and established as a reliable technique in a majority of cases. We report on our experience using a previously described technique specifically for difficult, unfavorable, or contraindicated cases and suggest the employment of this technique as an alternative method to facilitate endoscopic repair and possibly limit the need for an open approach.
Maximally reliable spatial filtering of steady state visual evoked potentials

Abstract Due to their high signal-to-noise ratio (SNR) and robustness to artifacts, steady state visual evoked potentials (SSVEPs) are a popular technique for studying neural processing in the human visual system. SSVEPs are conventionally analyzed at individual electrodes or linear combinations of electrodes which maximize some variant of the SNR. Here we exploit the fundamental assumption of evoked responses – reproducibility across trials – to develop a technique that extracts a small number of high SNR, maximally reliable SSVEP components. This novel spatial filtering method operates on an array of Fourier coefficients and projects the data into a low-dimensional space in which the trial-to-trial spectral covariance is maximized. When applied to two sample data sets, the resulting technique recovers physiologically plausible components (i.e., the recovered topographies match the lead fields of the underlying sources) while drastically reducing the dimensionality of the data (i.e., more than 90% of the trial-to-trial reliability is captured in the first four components). Moreover, the proposed technique achieves a higher SNR than that of the single-best electrode or the Principal Components. We provide a freely-available MATLAB implementation of the proposed technique, herein termed “Reliable Components Analysis”.
Diverse information integration and visualization

This paper presents and explores a technique for visually integrating and exploring diverse information. Researchers and analysts seeking knowledge and understanding of complex systems have increasing access to related, but diverse, data. These data provide an opportunity to consider entities of interest from multiple informational perspectives not available from any single, data or information type. These multiple perspectives are derived from diverse, but related data and integrated for simultaneous analysis. Our approach visualizes multiple entities across multiple perspectives where each perspective, or dimension, is an alternate partitioning of the entities. The partitioning may be based on inherent or assigned attributes such as meta-data or prior knowledge captured in annotations. The partitioning may also be directly derived from entity data; for example, clustering, or unsupervised classification, can be applied to multi-dimensional vector entity data to partition the entities into groups, or clusters. The same entities may be clustered on data from different experiment types or processing approaches. This reduction of diverse data/information on an entity to a series of partitions, or discrete (and unit-less) categories, allows the user to view the entities across diverse data without concern for data types and units. Parallel coordinate plots typically visualize continuous data across multiple dimensions. We adapt parallel coordinate plots for discrete values such as partition names to allow the comparison of entity patterns across multiple dimension for identifying trends and outlier entities. We illustrate this approach through a prototype, Juxter (short for Juxtaposer).
The Dangers of Extreme Counterfactuals

We address the problem that occurs when inferences about counterfactuals—predictions, ‘‘what-if’’ questions, and causal effects—are attempted far from the available data. The danger of these extreme counterfactuals is that substantive conclusions drawn from statistical models that fit the data well turn out to be based largely on speculation hidden in convenient modeling assumptions that few would be willing to defend. Yet existing statistical strategies provide few reliable means of identifying extreme counterfactuals. We offer a proof that inferences farther from the data allow more model dependence and then develop easyto-apply methods to evaluate how model dependent our answers would be to specified counterfactuals. These methods require neither sensitivity testing over specified classes of models nor evaluating any specific modeling assumptions. If an analysis fails the simple tests we offer, then we know that substantive results are sensitive to at least some modeling choices that are not based on empirical evidence. Free software that accompanies this article implements all the methods developed.
Small-signal amplification of period-doubling bifurcations in smooth iterated maps

Various authors have shown that, near the onset of a period-doubling bifurcation, small perturbations in the control parameter may result in much larger disturbances in the response of the dynamical system. Such amplification of small signals can be measured by a gain defined as the magnitude of the disturbance in the response divided by the perturbation amplitude. In this paper, the perturbed response is studied using normal forms based on the most general assumptions of iterated maps. Such an analysis provides a theoretical footing for previous experimental and numerical observations, such as the failure of linear analysis and the saturation of the gain. Qualitative as well as quantitative features of the gain are exhibited using selected models of cardiac dynamics.
Formal anti-Markovnikov hydroamination of terminal olefins

A new strategy to access linear amines from terminal olefin precursors is reported. This two-step, one-pot hydroamination methodology employs sequential oxidation and reduction catalytic cycles. The formal hydroamination transformation proceeds with excellent regioselectivity, and only the anti-Markovnikov product is observed. Up to 70% yield can be obtained from styrenes or aliphatic olefins and either primary or secondary aromatic amines. Additionally, the scope is broad with respect to the olefin and accommodates a variety of functionalities; we demonstrate that amines with removable aryl protecting groups may be utilized to allow access to a more diverse array of hydroamination adducts.
A machine-learning apprentice for the completion of repetitive forms

A non-intrusive assistant or apprentice is described that provides viable default values for blank fields in a form and highlights possible inconsistencies in completed fields. The focus is on the intermediate processing stage of form-filling, so the existence of an electronically reproduced on-screen form is assumed. The learning apprentice can be used for repetitious form-filling tasks. The authors establish the need for learning apprentices, describe a framework for such a system, and explain the difficulties of form-filling. Empirical results show that the system significantly reduced the number of keystrokes required to fill out repetitious forms by 87%, and correctly predicted nearly 90% of the values on the form. >
Nanomagnetic Structures: Fabrication and Interactions

Magnetic nanostructures with desirable properties such as monodispersed size and crystallographic texturing can be fabricated by a number of synthetic techniques. In this paper, we discuss methods for creating nanoclusters with fine control of individual propertiesand their interactions, as well as a promising chemical technique that provides control of several properties simultaneously. Current and potential applications also will be addressed.
Cluster galaxy dynamics and the effects of large-scale environment

Advances in observational capabilities have ushered in a new era of multi-wavelength, multi-physics probes of galaxy clusters and ambitious surveys are compiling large samples of cluster candidates selected in different ways. We use a high-resolution N-body simulation to study how the influence of large-scale structure in and around clusters causes correlated signals in different physical probes and discuss some implications this has for multi-physics probes of clusters (e.g. richness, lensing, Compton distortion and velocity dispersion). We pay particular attention to velocity dispersions, matching galaxies to subhaloes which are explicitly tracked in the simulation. We find that not only do haloes persist as subhaloes when they fall into a larger host, but groups of subhaloes retain their identity for long periods within larger host haloes. The highly anisotropic nature of infall into massive clusters, and their triaxiality, translates into an anisotropic velocity ellipsoid: line-of-sight galaxy velocity dispersions for any individual halo show large variance depending on viewing angle. The orientation of the velocity ellipsoid is correlated with the large-scale structure, and thus velocity outliers correlate with outliers caused by projection in other probes. We quantify this orientation uncertainty and give illustrative examples. Such a large variance suggests that velocity dispersion estimators will work better in an ensemble sense than for any individual cluster, which may inform strategies for obtaining redshifts of cluster members. We similarly find that the ability of substructure indicators to find kinematic substructures is highly viewing angle dependent. While groups of subhaloes which merge with a larger host halo can retain their identity for many Gyr, they are only sporadically picked up by substructure indicators. We discuss the effects of correlated scatter on scaling relations estimated through stacking, both analytically and in the simulations, showing that the strong correlation of measures with mass and the large scatter in mass at fixed observable mitigate line-of-sight projections.
Afterglow Observations Shed New Light on the Nature of X-Ray Flashes

X-ray flashes (XRFs) and X-ray rich gamma-ray bursts (XRGRBs) share many observational characteristics with long duration ({approx}> 2 s) GRBs, but the reason for which the spectral energy distribution of their prompt emission peaks at lower photon energies, E{sub p}, is still a subject of debate. Although many different models have been invoked in order to explain the lower values of E{sub p}, their implications for the afterglow emission were not considered in most cases, mainly because observations of XRF afterglows have become available only recently. Here we examine the predictions of the various XRF models for the afterglow emission, and test them against the observations of XRF 030723 and XRGRB 041006, the events with the best monitored afterglow light curves in their respective class. We show that most existing XRF models are hard to reconcile with the observed afterglow light curves, which are very flat at early times. Such light curves are, however, naturally produced by a roughly uniform jet with relatively sharp edges that is viewed off-axis (i.e. from outside of the jet aperture). This type of model self consistently accommodates both the observed prompt emission and the afterglow light curves of XRGRB 041006 and XRF 030723, implyingmore » viewing angles {theta}{sub obs} from the jet axis of ({theta}{sub obs}-{theta}{sub 0}) {approx} 0.15 {theta}{sub 0} and ({theta}{sub obs}-{theta}{sub 0}) {approx} {theta}{sub 0}, respectively, where {theta}{sub 0} {approx} 3{sup o} is the half-opening angle of the jet. This suggests that GRBs, XRGRBs and XRFs are intrinsically similar relativistic jets viewed from different angles. It is then natural to identify GRBs with {gamma}({theta}{sub obs} - {theta}{sub 0}) {approx} a few, where {gamma} is the Lorentz factor of the outflow near the edge of the jet from which most of the observed prompt emission arises. Future observations with Swift could help test this unification scheme in which GRBs, XRGRBs and XRFs share the same basic physics and differ only by their orientation relative to our line of sight.« less