cssi/SciSciGPT-SciSciNet huggingface dataset:
Interactions of charged spin-2 fields

In light of recent progress in ghost-free theories of massive gravity and multi-gravity, we reconsider the problem of constructing a ghost-free theory of an interacting spin-2 field charged under a U(1) gauge symmetry. Our starting point is the theory originally proposed by Federbush, which is essentially Fierz–Pauli generalized to include a minimal coupling to a U(1) gauge field. We show the Federbush theory with a dynamical U(1) field is in fact ghost-free and can be treated as a healthy effective field theory to describe a massive charged spin-2 particle. It can even potentially have healthy dynamics above its strong-coupling scale. We then construct candidate gravitational extensions to the Federbush theory both by using dimensional deconstruction, and by constructing a general nonlinear completion. However, we find that the U(1) symmetry forces us to modify the form of the Einstein–Hilbert kinetic term. By performing a constraint analysis directly in the first-order form, we show that these modified kinetic terms inevitably reintroduce the Boulware–Deser ghost. As a by-product of our analysis, we present a new proof for ghost-freedom of bi-gravity in 2+1 dimensions (also known as Zwei-Dreibein gravity). We also give a complementary algebraic argument that the Einstein–Hilbert kinetic term is incompatible with a U(1) symmetry, for a finite number of gravitons.
The Relationships Among Locus Of Control, Perceptions Of Stress And Performance

This study examines the relationship among locus of control (Rotter, 1966) perceived stress, and performance of 206 newly-hired juniors (106 males and 100 females) from two Big-Six accounting firms. The data indicate that the more internal the individuals locus of control, the more that individual perceived stress as leading to higher achievements. Positive perceptions of stress were also related to higher grade point averages.
Lower bounds for clear transmissions in radio networks

We show new lower bounds for collision-free transmissions in Radio Networks. Our main result is a tight lower bound of Ω(log n log (1/e)) on the time required by a uniform randomized protocol to achieve a clear transmission with success probability 1–e in a one-hop setting. This result is extended to non-uniform protocols as well. A new lower bound is proved for the important multi-hop setting of nodes distributed as a connected Random Geometric Graph. Our main result is tight for a variety of problems.
Toward economic diversification in Trinidad and Tobago

This paper contributes to the predominant diversification debate that has been ongoing in Trinidad and Tobago for more than three decades. The paper makes a determination of the key impediments to the country's attempts at diversification. Econometric techniques are applied on panel data to identify the most significant obstacles to economic diversification for a set of 183 countries. The results indicate that openness to foreign direct investment inflows is the most fundamental driver of diversification. The findings are then applied to the specific case of Trinidad and Tobago through a detailed analysis of the links in the trends followed by foreign direct investment and diversification between 1980 and 2011. Greater openness to foreign direct investment and improving the business climate appear to be key policies the twin-island republic could implement further in order to expand the range of activities of its economic structure.
A lower bound on the value of entangled binary games

A two-player one-round binary game consists of two cooperative players who each repliesby one bit to a message that he receives privately; they win the game if both questions andanswers satisfy some predetermined property. A game is called entangled if the playersare allowed to share a priori entanglement. It is well-known that the maximum winningprobability (value) of entangled XOR-games (binary games in which the predeterminedproperty depends only on the XOR of the two output bits) can be computed by asemidefinite program. In this paper we extend this result in the following sense; if abinary game is uniform, meaning that in an optimal strategy the marginal distributionsof the output of each player are uniform, then its entangled value can be efficientlycomputed by a semidefinite program. We also introduce a lower bound on the entangledvalue of a general two-player one-round game; this bound depends on the size of theoutput set of each player and can be computed by a semidefinite program. In particular,we show that if the game is binary, ωq is its entangled value, and ωsdp is the optimumvalue of the corresponding semidefinite program, then 0.68 ωsdp < ωq ≤ ωsdp.
Classifier evasion: models and open problems

As a growing number of software developers apply machine learning to make key decisions in their systems, adversaries are adapting and launching ever more sophisticated attacks against these systems. The near-optimal evasion problem considers an adversary that searches for a low-cost negative instance by submitting a minimal number of queries to a classifier, in order to effectively evade the classifier. In this position paper, we posit several open problems and alternative variants to the near-optimal evasion problem. Solutions to these problems would significantly advance the state-of-the-art in secure machine learning.
On Cherednik-Macdonald-Mehta identities

In this note we give a proof of Cherednik’s generalization of Macdonald–Mehta identities for the root system An−1, using representation theory of quantum groups. These identities give an explicit formula for the integral of a product of Macdonald polynomials with respect to a “difference analogue of the Gaussian measure”. They were suggested by Cherednik, who also gave a proof based on representation theory of affine Hecke algberas; our proof gives a nice interpretation for these identities in terms of representations of quantum groups and seems to be simpler than that of Cherednik. Introduction In this note we give a proof of Cherednik’s generalization of Macdonald–Mehta identities for the root system An−1, using representation theory of quantum groups. These identities, suggested and proved in [Ch2], give an explicit formula for the integral of a product of Macdonald polynomials with respect to a “difference analogue of the Gaussian measure”. They can be written for any reduced root system, or, equivalently, for any semisimple complex Lie algebra g. Assuming for simplicity that g is simple and simply laced, these identities are given by the following formula: 1 |W | ∫ δkδkPλPμγ dx = q 2+(μ,μ+2kρ)Pμ(q−2(λ+kρ)) × q−2k(k−1)|R+| ∏ α∈R+ k−1 ∏
Project performance and the locus of influence in the R&D matrix

This study examines the relationship between project performance and the relative influence of project and functional managers in 86 R&D teams in nine technology-based organizations. Performance re...
Bounding the CRRA Utility Functions

The constant-relative-risk-aversion (CRRA) utility function is now predominantly used in quantitative macroeconomic studies. This function, however, is not bounded and thus creates problems when applying the standard tools of dynamic programming. This paper devises a method for "bounding" the CRRA utility functions. The proposed method is based on a set of conditions that can establish boundedness among a broad class of utility functions. These results are then used to construct a bounded utility function that is identical to a CRRA utility function except when consumption is very small or very large. It is shown that the constructed utility function also satisfies the Inada condition and is consistent with balanced growth.
Power-Law Signatures and Patchiness in Genechip Oligonucleotide Microarrays

Genechip oligonucleotide microarrays have been used widely for transcriptional profiling of a large number of genes in a given paradigm. Gene expression estimation precedes biological inference and is given as a complex combination of atomic entities on the array called probes. These probe intensities are further classified into perfect-match (PM) and mismatch (MM) probes. While former is a measure of specific binding, the latter is a measure of non-specific binding. The behavior of the MM probes has especially proven to be elusive. The present study investigates qualitative similarities in the distributional signatures and local correlation structures/patchiness between the PM and MM probe intensities. These qualitative similarities are established on publicly available microarrays generated across laboratories investigating the same paradigm. Persistence of these similarities across raw as well as background subtracted probe intensities is also investigated. The results presented raise fundamental concerns in interpreting Genechip oligonucleotide microarray data.
Infiltration into fractured bedrock

experiment performed on fractured ash flow tuff. Water was released from a 3 � 4m 2 infiltration plot (divided into 12 square subplots) with a head of � 0.04 m, over a period of � 800 days. This experiment revealed peculiar infiltration patterns not amenable to current infiltration models, which were originally developed for infiltration into soils over a short duration. In particular, we observed that in part of the infiltration plot, the infiltration rate abruptly increased a few weeks into the infiltration tests. We suggest that these anomalies result from increases in fracture permeability during infiltration, which may be caused by swelling of clay fillings and/or erosion of infill debris. Interaction of the infiltration water with subsurface natural cavities (lithophysal cavities) could also contribute to such anomalies. This paper provides a conceptual model that partly describes the observed infiltration patterns in fractured rock and highlights some of the pitfalls associated with direct extension of soil infiltration models to fractured rock over a long period.
Energy landscape for large average submatrix detection problems in Gaussian random matrices

The problem of finding large average submatrices of a real-valued matrix arises in the exploratory analysis of data from a variety of disciplines, ranging from genomics to social sciences. In this paper we provide a detailed asymptotic analysis of large average submatrices of an $$n \times n$$ Gaussian random matrix. The first part of the paper addresses global maxima. For fixed k we identify the average and the joint distribution of the $$k \times k$$ submatrix having largest average value. As a dual result, we establish that the size of the largest square sub-matrix with average bigger than a fixed positive constant is, with high probability, equal to one of two consecutive integers that depend on the threshold and the matrix dimension n. The second part of the paper addresses local maxima. Specifically we consider submatrices with dominant row and column sums that arise as the local optima of iterative search procedures for large average submatrices. For fixed k, we identify the limiting average value and joint distribution of a $$k \times k$$ submatrix conditioned to be a local maxima. In order to understand the density of such local optima and explain the quick convergence of such iterative procedures, we analyze the number $$L_n(k)$$ of local maxima, beginning with exact asymptotic expressions for the mean and fluctuation behavior of $$L_n(k)$$ . For fixed k, the mean of $$L_{n}(k)$$ is $$\Theta (n^{k}/(\log {n})^{(k-1)/2})$$ while the standard deviation is $$\Theta (n^{2k^2/(k+1)}/(\log {n})^{k^2/(k+1)})$$ . Our principal result is a Gaussian central limit theorem for $$L_n(k)$$ that is based on a new variant of Stein’s method.
On Modeling and Estimation for the Relative Risk and Risk Difference

ABSTRACTA common problem in formulating models for the relative risk and risk difference is the variation dependence between these parameters and the baseline risk, which is a nuisance model. We address this problem by proposing the conditional log odds-product as a preferred nuisance model. This novel nuisance model facilitates maximum-likelihood estimation, but also permits doubly-robust estimation for the parameters of interest. Our approach is illustrated via simulations and a data analysis. An R package implementing the proposed methods is available on CRAN. Supplementary materials for this article are available online.
The topology of competitively constructed graphs

We consider a simple game, the $ k$ -regular graph game, in which players take turns adding edges to an initially empty graph subject to the constraint that the degrees of vertices cannot exceed $ k$ . We show a sharp topological threshold for this game: for the case $ k = 3$ a player can ensure the resulting graph is planar, while for the case $ k = 4$ , a player can force the appearance of arbitrarily large clique minors.
Natural history of paroxysmal nocturnal hemoglobinuria clones in patients presenting as aplastic anemia

Objective Investigate the natural history of PNH clones in patients with acquired aplastic anemia (AA).
Introduction: Environmental Sustainability Symposium

The issue of environmental sustainability is a controversial and extremely diverse multi-faceted topic that ranges from questions as to how to ensure that adequate investment in energy R&D and infrastructure will be undertaken, to state level renewable portfolio standards, to the impact of pollution havens on legislation that would enhance industrial greenhouse gas emission standards, to economic resilience to hurricane hazards, and to EPA policies. This paper summarizes seven studies that are devoted to exploring various aspects of the remarkably complex and diverse dimensions of environmental sustainability.
Incidence, case fatality and genotypes causing Clostridium difficile infections, Finland, 2008*

Since 2000, the epidemiology of C. difficile infections (CDI) has changed in the US and Europe. Few population-based assessments of both incidence and case fatality of CDI have been performed. In this study, the Finnish nationwide laboratory-based surveillance data from the year 2008 were analysed to assess the incidence and case fatality of CDI, and to detect regional differences in relation to molecular epidemiology. A total of 6201 episodes of CDI were identified (118.3/100 000 population; range by regions, 57.2-189.1). The incidence increased by age and was highest in persons aged >84 years (1286.0). Of the CDI episodes, 711 (11.5%; range by regions, 2.2-15.0%) led to death within 30 days. The 30-day case fatality was highest (22.0%) in persons aged >84 years. In total, 334 (5% of all episodes) isolates from 13/21 regions were sent for genotyping: 120 (36%) were of PCR ribotype 027, and it was found in 6/13 regions. Among the rest of the isolates, 53 (16%) were of type 001, and 19 (6%) of 002 and 014. The incidence and case fatality were highest in elderly persons and varied regionally. This may be explained by uneven spread of hypervirulent PCR ribotypes, such as 027, but also differences in diagnostic activity or the patient populations among which the outbreaks are occurring.
Information capacity of nonlinear fiber-optical systems

We develop information-theoretical description of nonlinear optical communication systems. We present a non-perturbative calculation of the information capacity for different modulation formats, and demonstrate that fiber nonlinearity leads to exponential suppression of the channel capacity.
Adaptive control of partially known systems

First presents modified parametrizations for model reference adaptive control of linear plants with partial knowledge of stable zero or pole dynamics. The modified adaptive controllers reduce the closed-loop system order by 2n/sub r/ where n/sub r/ is the order of the known dynamics. The author then applies such parametrizations to adaptive inverse control of plants with unknown nonsmooth nonlinearities such as a dead-zone, backlash or hysteresis at the input or output of a linear part whose stable zero or pole dynamics are partially known. The modified designs for nonlinear plants achieve an order reduction 2n/sub r/p where p is the number of parameters of the input or output nonlinearity.
Firm-level survey provides data on Asia's corporate crisis and recovery

Researchers have decried the limited supply of objective, comparable firm-level data from developing countries. The author describes a new database that helps fill this information gap. The database has detailed records on 4000 firms operating in Indonesia, the Republic of Korea, Malaysia, the Philippines, and Thailand. A comparable survey instrument and sampling methodology was used in each country, and all five studies were carried out simultaneously. The data cover three years (1996-98), allowing for measurements of firm performance before and immediately after the East Asian financial crisis. The questionnaire focused on measuring the impact of the regional financial crisis at the microeconomic level and understanding the longer-run determinants of productivity, employment practices, and financial structure. This database--the first step in the important Firm Analysis and Competitiveness Surveys initiative that the World Bank is spearheading--will be joined by additional country databases. The aim is to fill the gap in much-needed microeconomic evidence using comparable instruments.
Persistent topology for cryo-EM data analysis.

Summary In this work, we introduce persistent homology for the analysis of cryo-electron microscopy (cryo-EM) density maps. We identify the topological fingerprint or topological signature of noise, which is widespread in cryo-EM data. For low signal-to-noise ratio (SNR) volumetric data, intrinsic topological features of biomolecular structures are indistinguishable from noise. To remove noise, we employ geometric flows that are found to preserve the intrinsic topological fingerprints of cryo-EM structures and diminish the topological signature of noise. In particular, persistent homology enables us to visualize the gradual separation of the topological fingerprints of cryo-EM structures from those of noise during the denoising process, which gives rise to a practical procedure for prescribing a noise threshold to extract cryo-EM structure information from noise contaminated data after certain iterations of the geometric flow equation. To further demonstrate the utility of persistent homology for cryo-EM data analysis, we consider a microtubule intermediate structure Electron Microscopy Data (EMD 1129). Three helix models, an alpha-tubulin monomer model, an alpha-tubulin and beta-tubulin model, and an alpha-tubulin and beta-tubulin dimer model, are constructed to fit the cryo-EM data. The least square fitting leads to similarly high correlation coefficients, which indicates that structure determination via optimization is an ill-posed inverse problem. However, these models have dramatically different topological fingerprints. Especially, linkages or connectivities that discriminate one model from another, play little role in the traditional density fitting or optimization but are very sensitive and crucial to topological fingerprints. The intrinsic topological features of the microtubule data are identified after topological denoising. By a comparison of the topological fingerprints of the original data and those of three models, we found that the third model is topologically favored. The present work offers persistent homology based new strategies for topological denoising and for resolving ill-posed inverse problems. Copyright © 2015 John Wiley & Sons, Ltd.
Astrometric application of the photoelectric scanning technique

A new photoelectric area scanner, designed primarily for observations of double stars, has been put into routine use at the Lowell Observatory. A description of the scanner and of the associated data acquisition system is given. The procedure of measuring the relative positions of double star components is described and the accuracy obtainable by this method is discussed.
Machine Tool Chatter Suppression by Multi-Level Random Spindle Speed Variation

This paper presents a new method for varying the spindle speed to suppress chatter in machining. The spindle speed is varied in a pseudo-random fashion within the bandwidth of the spindle system. Both implementation issues and spindle system responses to such signals are investigated. A new method to analyze the stability of machining systems with varying spindle speed is also introduced. The effectiveness and advantages of the random spindle speed variation in chatter suppression is verified using numerical simulations and experiments.
A New Synthetic Approach to Salmeterol

Abstract In the present work a short and convenient route for the synthesis of salmeterol from salicylaldehyde has been developed.
Enantioselective Pd(II)-Catalyzed Aerobic Oxidative Amidation of Alkenes and Insights into the Role of Electronic Asymmetry in Pyridine-Oxazoline Ligands

Enantioselective intramolecular oxidative amidation of alkenes has been achieved using a (pyrox)Pd(II)(TFA)2 catalyst (pyrox = pyridine-oxazoline, TFA = trifluoroacetate) and O2 as the sole stoichiometric oxidant. The reactions proceed at room temperature in good-to-excellent yields (58–98%) and with high enantioselectivity (ee = 92–98%). Catalyst-controlled stereoselective cyclization reactions are demonstrated for a number of chiral substrates. DFT calculations suggest that the electronic asymmetry of the pyrox ligand synergizes with steric asymmetry to control the stereochemical outcome of the key amidopalladation step.
Synthesis of methyl α-d-glucopyranosyl-(1→4)-α-d-galactopyranoside and methyl α-d-xylo-hex-4-ulopyranosyl-(1→4)-α-d-galactopyranoside

The syntheses of methyl alpha-D-glucopyranosyl-(1-->4)-alpha-D-galactopyranoside (1) and methyl alpha-D-xylo-hex-4-ulopyranosyl-(1-->4)-alpha-D-galactopyranoside (4) are reported. The keto-disaccharide 4 is of interest in our design, synthesis, and study of pectate lyase inhibitors. The key step in the syntheses was the high-yielding, stereospecific formation of methyl 4,6-O-benzylidene-2',3'-di-O-benzyl-alpha-D-glucopyranosyl-(1-->4)-2,3,6-tri-O-benzyl-alpha-D-galactopyranoside (15), which was accomplished by reacting 2,3-di-O-benzyl-4,6-O-benzylidene-D-glucopyranosyl trichloroacetimidate (10) with methyl 2,3,6-tri-O-benzyl-alpha-D-galactopyranoside (14) in the presence of a catalytic amount of tert-butyldimethylsilyl trifluoromethane sulfonate (TMSOTF). Compound 15 was either hydrogenolyzed to yield disaccharide 1 or treated with NaBH3CN-HCl in 1:1 tetrahydrofuran-ether to yield methyl 2,3,6-tri-O-benzyl-alpha-D-glucopyranosyl-(1-->4)-2,3,6-tri-O-benzyl-alpha-D-galactopyranoside (2). The free 4'-OH of compound 2 was oxidized to a carbonyl group by a Swern oxidation, and the protecting groups were removed by hydrogenolysis to yield keto-disaccharide 4. These synthetic pathways were simple, yet high yielding.
Stereotactic radiosurgery for patients with acth-producing pituitary adenomas after prior adrenalectomy

Abstract Purpose : To review the results of stereotactic radiosurgery for patients with adrenocorticotropic hormone (ACTH)-producing pituitary adenomas after bilateral adrenalectomy. Methods and Materials : Eleven patients with ACTH-producing pituitary adenomas after bilateral adrenalectomy underwent radiosurgery between 1990 and 1999. Nine patients had documented tumor growth, hyperpigmentation, and elevated ACTH levels (median 920 ng/mL) at the time of radiosurgery. Five of these patients had tumor enlargement despite prior fractionated radiotherapy (median dose 50 Gy). Two patients were treated prophylactically within 1 month of their adrenalectomies to prevent future tumor growth. The median follow-up was 37 months (range 22–74). Results : Tumor growth control was achieved in 9 patients (82%); 2 patients had had continued tumor growth after radiosurgery. The ACTH levels decreased a median of 66% (range −99% to +27%); 4 patients had normal ACTH levels. Three patients had radiation-related complications, including diplopia (n = 2), ipsilateral blindness (n = 1), testosterone/growth hormone deficiency (n = 1), and asymptomatic temporal lobe radiation necrosis (n = 1): all had received prior radiotherapy. One patient who had undergone three prior resections and radiotherapy died 59 months after radiosurgery despite two additional attempts at tumor resection. Conclusion : Although our experience is limited, it appears that radiosurgery provides tumor control for most patients with ACTH-producing pituitary adenomas who have undergone bilateral adrenalectomy.
Strategic manipulability without resoluteness or shared beliefs: Gibbard-Satterthwaite generalized

The Gibbard-Satterthwaite Theorem on the manipulability of social-choice rules assumes resoluteness: there are no ties, no multi-member choice sets. Generalizations based on a familiar lottery idea allow ties but assume perfectly shared probabilistic beliefs about their resolution. We prove a more straightforward generalization that assumes almost no limit on ties or beliefs about them.
Domain knowledge and the design process

Abstract During the past 10 or 12 years, Artificial Intelligence researchers have explored techniques for bringing large amounts of domain knowledge to bear in solving ill-structured problems. Several programs that make use of these knowledge-based techniques are currently being developed to assist in various design tasks. This paper introduces one technique — rule-based programming — and illustrates its use with two programs, R1 and XSEL, which are used by Digital Equipment Corporation in the design of computer system configurations.
Surviving on the slope: Supersymmetric vacuum in the theories where it is not supposed to be

Abstract In supersymmetric models with the run-away vacua or with the stable but non-supersymmetric ground state there exist stable field configurations which restore one half of supersymmetry and are characterized by constant positive energy density. We call these solutions “vacua” since they are stable with respect to local deformations of the fields. The energy-momentum tensor for these configurations is proportional to diag{1,−1,−1,0}, i.e. they break (spontaneously) the Lorentz and rotational invariances. The formal foundation for such vacua is provided by the central extension of the N =1 superalgebra with the infinite central charge.
Novel formulation strategies for improving oral bioavailability of drugs with poor membrane permeation or presystemic metabolism

The oral route is most preferred for chronic drug therapy. Poor oral bioavailability has the consequences of more variable and poorly controlled plasma concentrations and drug effects, in addition to possibly increased product cost. In this review, the most common causes of low oral bioavailability are categorized, and formulation strategies to improve bioavailability are summarized. Various methods that can be used to help identify the cause of low bioavailability are discussed. The focus of this article is on poor membrane permeation and presystemic degradation problems; solubility/dissolution rate problems are discussed only briefly. Poor membrane permeation and presystemic degradation problems are typically encountered in the efforts to develop oral proteins, peptides, and peptide mimics. Formulation strategies reviewed include the use of metabolism inhibitors, membrane permeation enhancers, ion pairing and complexation, and particulate carriers. Also reviewed are lipid and surfactant formulations, which have been shown to increase bioavailability by various mechanisms and which are only beginning to be understood and optimized.
A short chemoenzymatic synthesis of (+)-narciclasine

Abstract The title alkaloid has been synthesized in eight operations from dibromobenzene and o -vanillin, via enzymatic oxidation of the former compound, Suzuki coupling and a Bischler-Napieralski type cyclization as the key transformations.
Effect of structured workshop training on subsequent performance of journal peer reviewers

Abstract Study objective: We sought to determine whether peer reviewers who attend a formal interactive training session produce better reviews. Methods: Peer reviewers were invited to attend a formal, 4-hour, highly interactive workshop on peer review. Attendees received a sample manuscript to read and review in writing in advance. The workshop included presentations on analyzing a study and the journal's expectations for a quality review, discussion of the sample manuscript's flaws and how to address them in a review, discussion of the reviews written by the attendees, and discussion of real reviews of other manuscripts illustrating key points. The performance of attendees on the basis of standard editor quality ratings (1 to 5) was assessed for the 2 years after workshop attendance. Control reviewers matched for previous review quality and volume were selected from nonattendees of the workshop. In study 1, all average reviewers received a standard written invitation. In study 2, 75 randomly selected average reviewers were personally and actively recruited with intensive follow-up by means of e-mail and telephone calls in an effort to reduce self-selection bias. Results: In study 1, 25 reviewers volunteered for the course, were eligible for study, attended, and were compared with 25 matched control reviewers. Of attendees filling out evaluations, 19% thought it somewhat and 81% thought it very helpful. All thought it would improve their subsequent reviews, and 85% thought it would improve their review ratings. The mean change in rating after the workshop was 0.11 (95% confidence interval [CI] −0.25 to 0.48) for control reviewers and 0.10 (95% CI −0.20 to 0.39) for attendees. In study 2, of 75 reviewers intensively recruited, only 12 (41%) of those who said they would attend did. All of the participants thought the workshop would improve their performance and ratings. Test scores at the end of the workshop improved in 73% of participants compared with scores on pretests. The control reviewers' average rating changed by −0.10 (95% CI −0.49 to 0.29) versus 0.06 (95% CI −0.34 to 0.23) for attendees. Conclusion: Among invited peer reviewers, voluntary attendance at a highly structured and interactive workshop was low and did not improve the quality of subsequent reviews, contrary to the predictions of attendees. Efforts to aggressively recruit average reviewers to a second workshop were time consuming, had low success rates, and showed a similar lack of effect on ratings, despite improvement in scores on a test instrument. Workshop teaching formats, although traditional, are of unproven efficacy. [ Ann Emerg Med. 2002;40:323-328.] Author contributions: MLC conceived and designed the study, collected data, drafted the manuscript, and takes responsibility for the paper as a whole. DLS designed the study, analyzed the data, and revised the manuscript. Both authors designed and conducted the workshop.
Impaired heart rate recovery is associated with new-onset atrial fibrillation: a prospective cohort study

Autonomic dysfunction appears to play a significant role in the development of atrial fibrillation (AF), and impaired heart rate recovery (HRR) during exercise treadmill testing (ETT) is a known marker for autonomic dysfunction. However, whether impaired HRR is associated with incident AF is unknown. We studied the association of impaired HRR with the development of incident AF, after controlling for demographic and clinical confounders. We studied 8236 patients referred for ETT between 2001 and 2004, and without a prior history of AF. Patients were categorized by normal or impaired HRR on ETT. The primary outcome was the development of AF. Cox proportional hazards modeling was used to control for demographic and clinical characteristics. Secondary analyses exploring a continuous relationship between impaired HRR and AF, and exploring interactions between cardiac medication use, HRR, and AF were also conducted. After adjustment, patients with impaired HRR were more likely to develop AF than patients with normal HRR (HR 1.43, 95% confidence interval (CI) 1.06, 1.93). In addition, there was a linear trend between impaired HRR and AF (HR 1.05 for each decreasing BPM in HRR, 95% CI 0.99, 1.11). No interactions between cardiac medications, HRR, and AF were noted. Patients with impaired HRR on ETT were more likely to develop new-onset AF, as compared to patients with normal HRR. These findings support the hypothesis that autonomic dysfunction mediates the development of AF, and suggest that interventions known to improve HRR, such as exercise training, may delay or prevent AF.
The Puzzle of Falling Enrolments in Physics and Chemistry Courses: Putting Some Pieces Together

This paper reports and discusses the principal findings of an Australian study exploring the decisions of high achieving Year 10 students about taking physics and chemistry courses (Lyons, 2003). The study used a ‘multiple worlds’ framework to explore the diverse background characteristics that previous quantitative research had shown were implicated in these decisions. Based on analyses of questionnaire and interview data, the study found that the students’ decisions involved the complex negotiation of a number of cultural characteristics within their school science and family worlds. Many of the students regarded junior high school science as irrelevant, uninteresting and difficult, leaving them with few intrinsic reasons for enrolling in senior science courses. The study found that decisions about taking physical science courses were associated with the resources of cultural and social capital within their families, and the degree to which these resources were congruent with the advantages of choosing these courses. The paper concludes that the low intrinsic value of school science and the erosion of its strategic value contribute to the reluctance of students to choose physical science courses in the senior school.
Whitehead products in function spaces: Quillen model formulae

We study Whitehead products in the rational homotopy groups of a general component of a function space. For the component of any based map f : X → Y , in either the based or free function space, our main results express the Whitehead product directly in terms of the Quillen minimal model of f . These results follow from a purely algebraic development in the setting of chain complexes of derivations of differential graded Lie algebras, which is of interest in its own right. We apply the results to study the Whitehead length of function space components.
Sterilization-associated deaths: A global survey

Except for data from several geographically limited studies, little is known globally about the number and causes of death associated with surgical sterilization. To identify clinical characteristics and problems leading to deaths related to the procedures, the International Planned Parenthood Federation (IPPF) and the Centers for Disease Control (CDC) in the United States collaborated in a global mail survey of 4642 physicians. Usable responses were received from 1298 physicians (28%) in 80 countries. Fifty-five sterilization-associated deaths which occurred from January 1, 1980 to June 30, 1982 were reported. The most frequently reported causes of death were infection, anesthetic complications, and hemorrhage. There were some regional differences in the relative frequencies of these causes. Most cases did not involve surgical accident. The characteristics most frequently associated with the reported fatal procedures were: interval sterilizations, minilaparotomy incision, tubal ligation and general anesthesia. Most deaths were attributable to the surgical sterilization procedure.
The Influence of Intensity of Egg Production Upon Infertility in the Domestic Fowl

Abstract INTRODUCTION The eggs produced by breeding flocks of apparently normal hens under systems of good management include various proportions which are infertile, the number sometimes ranging as high as 30 percent (15) 2 of the total incubated. With small numbers of birds or under adverse conditions much larger proportions of the eggs laid may be infertile. The causes of much, perhaps most, of this infertility remain unknown and additional knowledge concerning their control is essential to an adequate understanding of avian reproduction and to the diminution of such economic losses as now result from the incubation of infertile eggs. The objects of the present experiment were (1) to determine whether degree of infertility is influenced by the intensity of egg production in the fowl, and (2) to stud y the bases for such a relationship if it exists. MATERIALS AND METHODS During the 5-year period, 1935 to 1939, more than 1,200 . . .
Theory of current-drive in plasmas

The continuous operation of a tokamak fusion reactor requires, among other things, a means of providing continuously the toroidal current. Such operation is preferred to the conventional pulsed operation, where the plasma current is induced by a time-varying magnetic field. A variety of methods have been proposed to provide continuous current, including methods that utilize particle beams or radio-frequency waves in any of several frequency regimes. Currents as large as half a mega-amp have now been produced in the laboratory by such means, and experimentation in these techniques has now involved major tokamak facilities worldwide.
A new electrocardiographic classification for post-myocardial infarction clinical trials.

Abstract A new electrocardiographic code was developed for clinical trials involving patients with acute myocardial infarction (AMI). In the Multicenter Post-Infarction Program (MPIP), the electrocardiogram, classified by the Minnesota code, was not useful as a clinical predictor and played almost no role in subsequent analysis. To test its value the new code was applied to the electrocardiograms of 653 of the 866 patients in the MPIP data base who had sustained a first AMI. The MPIP code identifies AMI by region and severity. The 4 regions are anterior, lateral, inferior and posterior, defined by traditional criteria. Severity codes include Q-wave and non-Q-wave AMI, ST depression and no ischemic changes. The interpretation for each of 4 regions results in a 4-digit location severity code that is amenable to sorting and analysis. Fourteen separate and mutually exclusive groups were identified. Mortality gradients were found within the inferior AMI groups, but not within the anterior AMI groups. Mean ejection fraction was 50% for patients with isolated anterior infarction and decreased progressively (p
Mechanical alloying and reactive milling in a high energy planetary mill

Powder refinement in a planetary mill (Retsch PM 400-MA) is investigated experimentally and analyzed using discrete element modeling (DEM). Refinement is defined as the average size of the individual components in a composite powder. The specific milling dose, defined as the product of charge ratio and milling time, is used as an experimental parameter tracking the progress of the material refinement. This parameter is determined experimentally for milling of boron and titanium powders, for which the time of initiation of a self-sustained reaction is measured under different milling conditions. It is assumed that the reaction becomes self-sustaining when the same powder refinement is achieved. The DEM calculations established that the milling balls primarily roll along the milling container's perimeter. The inverse of the rate of energy dissipation resulting from this rolling motion is used as the DEM analog of the specific milling dose. The results correlate well with experimental observations.
Conformal collider physics: energy and charge correlations

We study observables in a conformal field theory which are very closely related to the ones used to describe hadronic events at colliders. We focus on the correlation functions of the energies deposited on calorimeters placed at a large distance from the collision. We consider initial states produced by an operator insertion and we study some general properties of the energy correlation functions for conformal field theories. We argue that the small angle singularities of energy correlation functions are controlled by the twist of non-local light-ray operators with a definite spin. We relate the charge two point function to a particular moment of the parton distribution functions appearing in deep inelastic scattering. The one point energy correlation functions are characterized by a few numbers. For = 1 superconformal theories the one point function for states created by the R-current or the stress tensor are determined by the two parameters a and c characterizing the conformal anomaly. Demanding that the measured energies are positive we get bounds on a/c. We also give a prescription for computing the energy and charge correlation functions in theories that have a gravity dual. The prescription amounts to probing the falling string state as it crosses the AdS horizon with gravitational shock waves. In the leading, two derivative, gravity approximation the energy is uniformly distributed on the sphere at infinity, with no fluctuations. We compute the stringy corrections and we show that they lead to small, non-gaussian, fluctuations in the energy distribution. Corrections to the one point functions or antenna patterns are related to higher derivative corrections in the bulk.
Sub-discretized surface model with application to contact mechanics in multi-body simulation

Abstract The mechanics of contact between rough and imperfectly spherical adhesive powder grains are often complicated by a variety of factors, including several which vary over sub-grain length scales. These include several traction factors that vary spatially over the surface of the individual grains, including high energy electron and acceptor sites (electrostatic), hydrophobic and hydrophilic sites (electrostatic and capillary), surface energy (general adhesion), geometry (van der Waals and mechanical), and elasto-plastic deformation (mechanical). For mechanical deformation and reaction, coupled motions, such as twisting with bending and sliding, as well as surface roughness add an asymmetry to the contact force which invalidates assumptions for popular models of contact, such as the Hertzian and its derivatives [H. Hertz, Uber die Beruhrung fester elastische korper. Journal fur die reine und angewandte Mathematik 1882; 92: 156-171; R.D. Mindlin, Compliance of elastic bodies in contact. Journal of Applied Mechanics 1949; 71: 259-268; R.D. Mindlin, H. Deresiewicz, Elastic spheres in contact under varying oblique forces. Journal of Applied Mechanics 1953; 20: 269-286], for the non-adhesive case, and the JKR [K.L. Johnson, K. Kendall, A.D. Roberts, Surface energy and the contact of elastic solids. Proceedings of the Royal Society of London 1971; 324: 301-313] and DMT [B.V. Derjaguin, V.M. Muller, Y.P. Toporov, Effect of contact deformations on the adhesion of particles. Journal of Colloid and Interface Science 1975; 53: 314-326] models for adhesive contacts. Though several contact laws have been offered to ameliorate these drawbacks, they are often constrained to particular loading paths (most often normal loading) and are relatively complicated for computational implementation. This paper offers a simple and general computational method for augmenting contact law predictions in multi-body simulations through characterization of the contact surfaces using a hierarchically-defined surface sub-discretization. For the case of adhesive contact between powder grains in low-stress regimes, this technique can allow a variety of existing contact laws to be resolved across scales, allowing for moments and torques about the contact area as well as normal and tangential tractions to be resolved. This is especially useful for multi-body simulation applications where the modeler desires statistical distributions and calibration for parameters in contact laws commonly used for resolving near-surface contact mechanics. The approach is verified against analytical results for the case of rough, elastic spheres.
Well-defined (N-heterocyclic carbene)–Ag(I) complexes as catalysts for A3 reactions

The use of well-defined (N-heterocyclic carbene)-Ag(I) complexes for the A(3) reaction allows for the coupling of unactivated aldehydes at room temperature and very short reaction times.
Particle size, magnetic field, and blood velocity effects on particle retention in magnetic drug targeting.

Purpose: A physics-based model of a general magnetic drug targeting (MDT) system was developed with the goal of realizing the practical limitations of MDT when electromagnets are the source of the magnetic field. Methods: The simulation tracks magnetic particles subject to gravity, drag force, magnetic force, and hydrodynamic lift in specified flow fields and external magnetic field distributions. A model problem was analyzed to determine the effect of drug particle size, blood flow velocity, and magnetic field gradient strength on efficiency in holding particles stationary in a laminar Poiseuille flow modeling blood flow in a medium-sized artery. Results: It was found that particle retention rate increased with increasing particle diameter and magnetic field gradient strength and decreased with increasing bulk flow velocity. Conclusions: The results suggest that MDT systems with electromagnets are unsuitable for use in small arteries because it is difficult to control particles smaller than about 20 μ m in diameter.
Suzuki Cross‐coupling Method to Prepare 4,4″‐Diamino‐p‐terphenyl

The synthesis of 4,4″‐dinitro‐p‐terphenyl is accomplished by double Suzuki cross‐coupling. The product was reduced catalytically to give 4,4″‐diamino‐p‐terphenyl in 75% overall yield.
Design and synthesis of (E)-1-((3-ethyl-2,4,4-trimethylcyclohex-2-enylidene)methyl-4-substituted benzenes from 1-(2,6,6-trimethylcyclohex-1-enyl)ethanol

A novel strategy for synthesizing (E)-1-((3-ethyl-2,4,4-trimethylcyclohex-2-enylidene)methyl-4-substituted benzenes from 1-(2,6,6-trimethylcyclohex-1-enyl)ethanol3 has been developed; the allylicalcohol3 was treated with PPh3·HBr in methanol followed by aldehydes in the presence of a base and furnished the 1,3-dienes in moderate to good yields (79–86%).
Flight Testing of a Reconfigurable Control System on an Unmanned Aircraft

A radio-controlled aircraft was built and equipped with air-data and inertial sensors. A radio frequency link was added to transmit data and receive commands from a ground station. Data from several flight tests were used to characterize the dynamic response of the aircraft. Despite the high level of noise associated with the low-cost sensor suite, consistent identification of critical aircraft parameters was obtained. Flight tests were also conducted with actuator failures induced on one elevator, one aileron, and one engine. Recursive parameter identification produced parameters tracking the effects of the failures, such as reduced effectiveness of pitch commands due to a locked elevator, or roll and sideslip due to engine failure. The identified parameters were also used in reconfigurable control experiments, where knowledge of the aircraft parameters was used to compensate for the effect of failures, reducing the pilot's workload. Overall, the paper demonstrates that recursive identification and reconfigurable control algorithms are implementable in real-time, even in low-cost platforms. They can be designed to effectively compensate for actuator failures and aircraft damage.
Diels-Alder reactions of 2-alkenylboranes and cis-1-alkenylboranes. Anomalous selectivity that allows a choice of regiochemistry

Abstract 2-Alkenyl- and cis -1-alkenylboranes are highly reactive Diels-Alder dienophiles which display unusual selectivity patters. By taking advantage of a reversal of regiochemistry of reaction with alkenyldihalo- versus alkenyldialkylboranes, any desired regioisomeric product may be favored, usually with very high selectivity.