cssi/SciSciGPT-SciSciNet huggingface dataset:
The geometry of relative arbitrage

Consider an equity market with n stocks. The vector of proportions of the total market capitalizations that belong to each stock is called the market weight. The market weight defines the market portfolio which is a buy-and-hold portfolio representing the performance of the entire stock market. Consider a function that assigns a portfolio vector to each possible value of the market weight, and we perform self-financing trading using this portfolio function. We study the problem of characterizing functions such that the resulting portfolio will outperform the market portfolio in the long run under the conditions of diversity and sufficient volatility. No other assumption on the future behavior of stock prices is made. We prove that the only solutions are functionally generated portfolios in the sense of Fernholz. A second characterization is given as the optimal maps of a remarkable optimal transport problem. Both characterizations follow from a novel property of portfolios called multiplicative cyclical monotonicity.
The Acceptability of War and Support for Defense Spending Evidence from Fourteen Democracies, 2004-2013

We study the factors that influence citizen support for defense spending in fourteen democracies over the period 2004–2013. We pose two research questions. First, what factors influence citizen support for war and military force? We refer to this as the acceptability of war. Second, in addition to the acceptability of war, what other factors affect support for defense spending? Our principal finding is that citizen acceptance of war and support for defense spending are most influenced by basic beliefs and values. Gender also has a strong negative influence on attitudes toward war and thus indirectly lowers support for defense spending among women. Attitudes toward war and defense spending are also sometimes influenced by short-term threats and by alliance considerations, but the effects are not as substantively meaningful. We conclude with a summary of the results and a discussion of the implications for theory and policy.
Fast matrix multiplication using coherent configurations

We introduce a relaxation of the notion of tensor rank, called s-rank, and show that upper bounds on the s-rank of the matrix multiplication tensor imply upper bounds on the ordinary rank. In particular, if the "s-rank exponent of matrix multiplication" equals 2, then ω = 2. This connection between the s-rank exponent and the ordinary exponent enables us to significantly generalize the group-theoretic approach of Cohn and Umans, from group algebras to general algebras. Embedding matrix multiplication into general algebra multiplication yields bounds on s-rank (not ordinary rank) and, prior to this paper, that had been a barrier to working with general algebras.We identify adjacency algebras of coherent configurations as a promising family of algebras in the generalized framework. Coherent configurations are combinatorial objects that generalize groups and group actions; adjacency algebras are the analogue of group algebras and retain many of their important features. As with groups, coherent configurations support matrix multiplication when a natural combinatorial condition is satisfied, involving triangles of points in their underlying geometry.Finally, we prove a closure property involving symmetric powers of adjacency algebras, which enables us to prove nontrivial bounds on ω using commutative coherent configurations and suggests that commutative coherent configurations may be sufficient to prove ω = 2. Altogether, our results show that bounds on ω can be established by embedding large matrix multiplication instances into small commutative coherent configurations.
Microtubule Flux and Sliding in mitotic spindles of Drosophila Embryos

We proposed that spindle morphogenesis in Drosophila embryos involves progression through four transient isometric structures in which a constant spacing of the spindle poles is maintained by a balance of forces generated by multiple microtubule (MT) motors and that tipping this balance drives pole-pole separation. Here we used fluorescent speckle microscopy to evaluate the influence of MT dynamics on the isometric state that persists through metaphase and anaphase A and on pole-pole separation in anaphase B. During metaphase and anaphase A, fluorescent punctae on kinetochore and interpolar MTs flux toward the poles at 0.03 μm/s, too slow to drive chromatid-to-pole motion at 0.11 μm/s, and during anaphase B, fluorescent punctae on interpolar MTs move away from the spindle equator at the same rate as the poles, consistent with MT-MT sliding. Loss of Ncd, a candidate flux motor or brake, did not affect flux in the metaphase/anaphase A isometric state or MT sliding in anaphase B but decreased the duration of the isometric state. Our results suggest that, throughout this isometric state, an outward force exerted on the spindle poles by MT sliding motors is balanced by flux, and that suppression of flux could tip the balance of forces at the onset of anaphase B, allowing MT sliding and polymerization to push the poles apart.
Einstein manifolds and contact geometry

We show that every K-contact Einstein manifold is SasakianEinstein and discuss several corollaries of this result.
Parameter inference and model selection in deterministic and stochastic dynamical models via approximate Bayesian computation: modeling a wildlife epidemic

We consider the problem of selecting deterministic or stochastic models for a biological, ecological, or environmental dynamical process. In most cases, one prefers either deterministic or stochastic models as candidate models based on experience or subjective judgment. Because of the complex or intractable likelihood in most dynamical models, likelihood-based approaches for model selection are not suitable. We use approximate Bayesian computation for parameter estimation and model selection to gain further understanding of the dynamics of two epidemics of chronic wasting disease in mule deer. The main novel contribution of this work is that, under a hierarchical model framework, we compare three types of dynamical models: ordinary differential equation, continuous-time Markov chain, and stochastic differential equation models. To our knowledge, model selection between these types of models has not appeared previously. Because the practice of incorporating dynamical models into data models is becoming more common, the proposed approach may be very useful in a variety of applications. Copyright © 2015 John Wiley & Sons, Ltd.
HiFive: a tool suite for easy and efficient HiC and 5C data analysis

The chromatin interaction assays 5C and HiC have advanced our understanding of genomic spatial organization, but analysis approaches for these data are limited by usability and flexibility. The HiFive tool suite provides efficient data handling and a variety of normalization approaches for easy, fast analysis and method comparison. Integration of MPI-based parallelization allows scalability and rapid processing time. In addition to single-command analysis of an entire experiment from mapped reads to interaction values, HiFive has been integrated into the open-source, web-based platform Galaxy to connect users with computational resources and a graphical interface. HiFive is open-source software available from http://taylorlab.org/software/hifive/.
Financial Services and Preferential Trade Agreements: Lessons from Latin America

This book deals with financial liberalization issues in the context of trade negotiations. The liberalization of trade and investment in financial services is only a subset of the broader financial liberalization agenda. The purpose of trade and investment liberalization is to increase financial market access and remove discriminatory and other access-impeding barriers to foreign competition. By contrast, the main purpose of financial liberalization is to remove distortions in domestic financial systems that impede competition and the allocation of capital to its most productive and profitable uses. In turn, financial liberalization can be divided into domestic financial reform and capital account opening, and there is a rich literature on its appropriate speed and sequencing. The first part of the book covers the fundamental principles that affect trade liberalization in financial services at both the multilateral and the regional levels. It analyzes the various models of preferential trade agreements (PTAs) used by negotiators and the architectural differences of these models. The second part of this book provides concrete examples of how countries have negotiated these agreements by focusing on the specific country experiences of Chile, Colombia, and Costa Rica. These case studies provide the reader with a thorough understanding of how countries strategize, negotiate, and implement regional trade agreements in financial services.
Geographic Dispersion of Economic Shocks: Evidence from the Fracking Revolution

Abstract We track the geographic and temporal propagation of local economic shocks from new oil and gas production generated by hydrofracturing. Each million dollars of new production produces $80,000 in wage income and $132,000 in royalty and business income within a county. Within 100 miles, one million dollars of new production generates $257,000 in wages and $286,000 in royalty and business income. Roughly two-thirds of the wage income increase persists for two years. Assuming no general equilibrium effects, new extraction increased aggregate US employment by as many as 640,000, and decreased the unemployment rate by 0.43 during the Great Recession. (JEL D86, L14, L81, L82)
The Affordable Care Act and Access to Care for People Changing Coverage Sources

Objectives. We investigated how access to and continuity of care might be affected by transitions between health insurance coverage sources, including the Marketplace (also called the Exchange), Medicaid, and the Children’s Health Insurance Program (CHIP).Methods. From January to February 2014 and from August to September 2014, we searched provider directories for networks of primary care physicians and selected pediatric specialists participating in Marketplace, Medicaid, and CHIP in 6 market areas of the United States and calculated the degree to which networks overlapped.Results. Networks of physicians in Medicaid and CHIP were nearly identical, meaning transitions between those programs may not result in much physician disruption. This was not the case for Marketplace and Medicaid and CHIP networks.Conclusions. Transitions from the Marketplace to Medicaid or CHIP may result in different degrees of physician disruption for consumers depending on where they live and what type of Marketplace product they...
Before main banks : a selective historical overview of Japan's prewar financialsystem

Among lessons learned from Japan's prewar financial system: Business conglomerates that did not remain dependent on government patronage were more successful than others in making the transition to a modern industrial economy. And banks that made a conscious effort to reduce their dependence on central bank credit were more successful than those that did not. The postwar experience of the Japanese banking system has received considerable attention recently partly because conditions in defeated Japan in 1945 (including high inflation and the need to switch from a military to a civilian economy) are similar to those in transition economies today. Policymakers in transition economies can learn a good deal from the experiences of Japan's postwar financial system but should remember that Japan also experienced extraordinary industrial growth and financial institution building in the late nineteenth and early twentieth centuries. Lessons to be learned from that experience include the following: ° Business conglomerates that did not continue to depend on government patronage were more successful than others in making the transition to a modern industrial economy. ° Banks that made a conscious effort to reduce their dependence on central bank credit were more successful than those that did not. ° The establishment of procedures for punishing defaulting borrowers helped the development of the payments system. ° Limits on the amount of lending to related parties appear to have contributed to financial stability (and could have contributed more if the newer zaibatsu had been as prudent as the older ones). ° Bank bailouts without accompanying reform (such as those the Bank of Japan undertook in 1920 and 1922) probably increased the likelihood of a more serious crisis, such as that of 1927. ° Capital standards - the minimum capital requirements established in the 1927 law - were a viable means of encouraging bank consolidation and more prudent lending. ° The public financial system served as a buffer when the banking sector was downsized. This paper - a joint product of the Finance and Private Sector Development Division, Policy Research Department, and the Financial Sector Development Department - was presented at a Bank seminar, Financial History: Lessons of the Past for Reformers of the Present, and is a chapter in a forthcoming volume, Reforming Finance: Some Lessons from History, edited by Gerard Caprio, Jr. and Dimitri Vittas.
Sensitivity Analysis for Multiple Comparisons in Matched Observational Studies Through Quadratically Constrained Linear Programming

ABSTRACTA sensitivity analysis in an observational study assesses the robustness of significant findings to unmeasured confounding. While sensitivity analyses in matched observational studies have been well addressed when there is a single outcome variable, accounting for multiple comparisons through the existing methods yields overly conservative results when there are multiple outcome variables of interest. This stems from the fact that unmeasured confounding cannot affect the probability of assignment to treatment differently depending on the outcome being analyzed. Existing methods allow this to occur by combining the results of individual sensitivity analyses to assess whether at least one hypothesis is significant, which in turn results in an overly pessimistic assessment of a study's sensitivity to unobserved biases. By solving a quadratically constrained linear program, we are able to perform a sensitivity analysis while enforcing that unmeasured confounding must have the same impact on the treatm...
The Timeliness of Accounting Write‐Downs by U.S. Financial Institutions During the Financial Crisis of 2007–2008

I examine the timeliness of write-downs taken by U.S. financial institutions during the financial crisis of 2007–2008. The timeliness of write-downs is measured by benchmarking the quarterly accounting write-down schedule with the devaluation schedule implied by exposure-specific credit indices such as the ABX. The results show that the accounting write-downs are less timely than the devaluations implied by credit indices. In a cross-sectional analysis of the determinants of the timeliness of write-downs, I document that corporate governance quality, regulatory investigations, and litigation pressure are positively related to the timeliness of write-downs, whereas the write-downs by firms with higher financial leverage, tighter regulatory constraints, and more complex exposures are less timely. I control for numerous exposure-specific characteristics and document that less risky exposures and exposures that were affected later during the financial crisis were written down later. Regarding the consequences of timeliness, I find that the exposure to risky assets is reflected faster in stock returns for firms with timelier write-downs.
Partitioned Shape Modeling with On-the-Fly Sparse Appearance Learning for Anterior Visual Pathway Segmentation

MRI quantification of cranial nerves such as anterior visual pathway (AVP) in MRI is challenging due to their thin small size, structural variation along its path, and adjacent anatomic structures. Segmentation of pathologically abnormal optic nerve (e.g. optic nerve glioma) poses additional challenges due to changes in its shape at unpredictable locations. In this work, we propose a partitioned joint statistical shape model approach with sparse appearance learning for the segmentation of healthy and pathological AVP. Our main contributions are: (1) optimally partitioned statistical shape models for the AVP based on regional shape variations for greater local flexibility of statistical shape model; (2) refinement model to accommodate pathological regions as well as areas of subtle variation by training the model on-the-fly using the initial segmentation obtained in (1); (3) hierarchical deformable framework to incorporate scale information in partitioned shape and appearance models. Our method, entitled PAScAL (PArtitioned Shape and Appearance Learning), was evaluated on 21 MRI scans (15 healthy + 6 glioma cases) from pediatric patients (ages 2–17). The experimental results show that the proposed localized shape and sparse appearance-based learning approach significantly outperforms segmentation approaches in the analysis of pathological data.
Macroeconomic shocks and banking sector developments in Egypt

From 2008 to 2011, Egypt was hit by significant shocks, both global and country-specific. This paper assesses the impact of the resulting macroeconomic instability on the banking sector, and examines its role as a shock absorber. The Central Bank of Egypt accommodated the shocks by supplying liquidity to the market. The paper verifies a change in the fiscal regime from one in which the primary fiscal balance was used an instrument to stabilize the public debt ratio to one in which the policy instrument stopped playing that role and affected investors' assessment of the risk of holding public debt. This pattern suggests that fiscal conditions influenced exchange rate and price expectations originating a fiscal dominance situation in which the Central Bank could not control inflation. Hence, the Central Bank lacked functional independence in spite of its de jure independence, which underscores the importance of strengthening institutions that facilitate policy coordination and allow policy to be more predictable. The government also funds itself through non-market mechanisms, in a typical financial repression scheme. The paper estimates the revenue from financial repression at about 2.5 percent of gross domestic product in 2011, which together with the revenues from seignoriage add up to close to 50 percent of the budgeted tax revenues, indicating the need for an in-depth review of the governance of the public banks and the funding of public sector activities. Finally, the paper estimates the impact of shocks to macroeconomic variables on loan portfolio quality and bank capital.
Investigating a solar influence on cloud cover using the North American Regional Reanalysis data

The controversial connection between cosmic rays, solar activity, and cloud cover is investigated using a climatological reconstructed reanalysis product: the North American Regional Reanalysis which provides high-resolution, low, mid-level, high, and total cloud cover data over a Lambert conformal conic projection permitting land/ocean discrimination. Pearson’s product-moment regional correlations were obtained between monthly cloud cover data and solar variability indicators, cosmic ray neutron monitors, several climatological indices, including the Atlantic Multidecadal Oscillation (AMO), and between cloud layers. Regions of the mid-latitude oceans exhibited a positive correlation with cosmic ray flux. Additionally, this maritime low cloud cover exhibits the only failed correlation significance with other altitudes. The cross correlation reveals that cloud cover is positively correlated everywhere but for ocean low cloud cover, supporting the unique response of the marine layer. The results of this investigation suggest that with the assumption that solar forcing does impact cloud cover, measurements of solar activity exhibits a slightly higher correlation than GCRs. The only instance where GCRs exhibit a positive regional correlation with cloud cover is for maritime low clouds. The AMO exerts the greatest control of cloud cover in the NARR domain.
New theoretical results on the proton decay of deformed and near-spherical nuclei

We discuss new theoretical results on the decay of deformed and near-spherical nuclei. We interpret the latest experimental results on deformed odd-A proton emitters, including fine structure, and discuss the use of particle-vibration coupling to calculate the decay rates of near-spherical emitters.
An analysis of genetic variation among intraspecific hybrids in Grindelia camporum (asteraceae)

Abstract Plants from seven wild populations of gumweed (Grindelia camporum) were crossed to produce (1) a population of 70 fullsib families and (2) a diallelic population of 15 interrelated fullsib and halfsib families. The fullsib family evaluation showed that performances of crosses were predictable based on prior knowledge of characteristics of the source populations from which parents were chosen. The diallelic study demonstrated the presence of nonadditive genetic variation in Grindelia for resin yield, biomass yield, earliness, post-harvest mortality, and several morphological traits. This study demonstrates the importance of genetic evaluations of phenotypic variation in domestication studies of energy-, biomass-, or chemical-producing plants. Knowledge of the amount and type of genetic variation will determine the potential for improvement in agronomic and economic traits in such new crops.
The first synthesis and characterization of both diastereomers of a di[2.2]paracyclophane: 4,4'-bis(1,1,2,2,9,9,10,10-octafluoro[2.2]paracyclophane).

The synthesis and characterization of both diastereomers of a system comprised of two [2.2]paracyclophane units linked through a single 4,4‘ bond are described. Both the meso and d,l diastereomers of 4,4‘-bis(octafluoro[2.2]paracyclophane) have been prepared via a palladium-catalyzed reductive homocoupling reaction by copper, producing a 3:2 ratio of meso and d,l diastereomers. A similar reductive homocoupling of pseudo-o-iodotrifluoromethyloctafluoro[2.2]paracyclophane gave only the analogous meso diastereomer. Single-crystal X-ray structures were obtained for all of the diparacyclophane products.
A Bernstein type theorem for self-similar shrinkers

In this paper, we prove that smooth self-shrinkers in \({\mathbb R^{n+1}}\), that are entire graphs, are hyperplanes. Previously, Ecker and Huisken showed that smooth self-shrinkers, that are entire graphs and have at most polynomial growth, are hyperplanes. The point of this paper is that no growth assumption at infinity is needed.
Combinatorial genericity and minimal rigidity

A well studied geometric problem, with applications ranging from molecular structure determination to sensor networks, asks for the reconstruction of a set P of n unknown points from a finite set of pairwise distances (up to Euclidean isometries). We are concerned here with a related problem: which sets of distances are minimal with the property that they allow for the reconstruction of P, up to a finite set of possibilities? In the planar case, the answer is known generically via the landmark Maxwell-Laman Theorem from Rigidity Theory, and it leads to a combinatorial answer: the underlying structure of such a generic minimal collection of distances is a minimally rigid (or Laman) graph, for which very efficient combinatorial decision algorithms exist. For non-generic cases the situation appears to be dramatically different, with the best known algorithms relying on exponential-time Grobner base methods, and some specific instances known to be NP-hard. Understanding what makes a point set generic emerges as an intriguing geometric question with practical algorithmic consequences.Several definitions (some but not all equivalent) of genericity appear in the rigidity literature, and they have either a measure theoretic, topologic or algebraic-geometric flavor. Some generic point sets appear to be highly degenerate, and still turn out to be generic. All existing proofs of Laman's Theorem make use at some point of one or another of these geometric genericity assumptions.The main result of this paper is the first purely combinatorial proof of Laman's theorem, together with some interesting consequences. Genericity is characterized in terms of a certain determinant being not identically-zero as a formal polynomial. We relate its monomial expansion to certain colorings and orientations of the graph and show that these terms cannot all cancel exactly when the underlying graph is Laman. As a surprising consequence, genericity emerges as a purely combinatorial concept.
ZnCdSe/ZnCdMgSe quantum well infrared photodetector

We report the design, fabrication and characterization of a II-VI Zn0.51Cd0.49Se / Zn0.45Cd0.42Mg0.13Se-based quantum well infrared photodetector (QWIP) with a bound to quasi-bound transition centered at 8.7 µm. The good growth quality of the epitaxial layers was verified by x-ray diffraction measurements. Absorption and photocurrent measurements yield results consistent with conventional III-V QWIPs. Photocurrent measurements reveal an exponential decrease with temperature. In addition, we also observe more than 4 orders of magnitude increase in photocurrent with applied bias. By compensating the drop in temperature performance with an increase in applied bias, we achieve an operating temperature of up to 140K and a responsivity of 1-10 µA/W.
Nucleosynthesis and Evolution of Massive Metal-Free Stars

The evolution and explosion of metal-free stars with masses 10-100 M ? are followed, and their nucleosynthetic yields, light curves, and remnant masses determined. Such stars would have been the first to form after the big bang and may have left a distinctive imprint on the composition of the early universe. When the supernova yields are integrated over a Salpeter initial mass function (IMF), the resulting elemental abundance pattern is qualitatively solar, but with marked deficiencies of odd-Z elements with 7 ? Z ? 13. Neglecting the contribution of the neutrino wind from the neutron stars that they form, no appreciable abundances are made for elements heavier than germanium. The computed pattern compares favorably with what has been observed in metal-deficient stars with [Z] ?3. The amount of ionizing radiation from this generation of stars is ~2.16 MeV per baryon (4.15 B per M ?; where 1 B = 1 Bethe = 1051 erg) for a Salpeter IMF, and may have played a role in reionizing the universe. Neglecting rotation, most of the stars end their lives as blue supergiants and form supernovae with distinctive light curves resembling SN 1987A, but some produce primary nitrogen due to dredge-up and become red supergiants. These make brighter supernovae like typical Type IIp's. For the lower mass supernovae considered, the distribution of remnant masses clusters around typical modern neutron star masses, but above 20-30 M ?, with the value depending on explosion energy, black holes are copiously formed by fallback, with a maximum hole mass of ~40 M ?. A novel automated fitting algorithm is developed for determining optimal combinations of explosion energy, mixing, and IMF in the large model database to agree with specified data sets. The model is applied to the low-metallicity sample of Cayrel et?al. and the two ultra-iron-poor stars HE0107-5240 and HE1327-2326. Best agreement with these very low metallicity stars is achieved with very little mixing, and none of the metal-deficient data sets considered show the need for a high-energy explosion component. In contrast, explosion energies somewhat less than 1.2 B seem to be preferred in most cases.
Active Multiple Winglets for Improved Unmanned-Aerial-Vehicle Performance

The addition of a winglet to a flight vehicle is known to enhance cruise performance. The addition of multiple, active winglets to an existing unmanned aerial vehicle (UAV) is studied to determine the potential of these devices to augment both cruise and maneuvering performance. Passive and active multiple winglets are shown to increase range and endurance, providing the potential for increased payload. Active multiple winglets are shown to be a viable replacement for ailerons and to provide gust alleviation for improved handling qualities and sensor performance. Two methods of predicting winglet performance enhancements are applied and compared to the U.S. Marine Corps Dragon Eye UAV configuration. Nomenclature az = normal acceleration C = specific fuel consumption CDi = induced drag coefficient CL = lift coefficient D = drag E = endurance e = efficiency factor g = gust K = induced drag constant K1, K2 = proportionality constant L = lift R = range S = wing area W = weight � = propeller efficiency
Comparison of chemical and enzymatic synthesis of 2-acetamido-2-deoxy-d-mannose 6-phosphate: a new approach

Chemical and enzymatic methods to synthesis of 2-acetamido-2-deoxy-D-mannose-6-phosphate (ManNAc-6-P) have been investigated. A new preparative method has been developed although some established procedures were tried. In this new method, a 6-O-acetyl or 4,6-di-O-acetyl group of the per-O-acetylated 2-acetamido-2-deoxy-D-mannose (ManNAc) were regioselectively removed with an esterase from the yellow yeast, Rhodosporidium toruloides, followed by phosphorylation and O-deacetylation under mild conditions. 1H and 13C NMR data spectra of ManNAc-6-P were recorded.
Internal Kinematics of the Fornax Dwarf Spheroidal Galaxy

We present new radial velocity results for 176 stars in the Fornax dwarf spheroidal galaxy, of which at least 156 are probable Fornax members. We combine with previously published data to obtain a radial velocity sample with 206 stars, of which at least 176 are probable Fornax members. We detect the hint of rotation about an axis near Fornax's morphological minor axis, although the significance of the rotation signal in the galactic rest frame is sensitive to the adopted value of Fornax's proper motion. Regardless, the observed stellar kinematics is dominated by random motions, and we do not find kinematic evidence of tidal disruption. The projected velocity dispersion profile of the binned data set remains flat over the sampled region, which reaches a maximum angular radius of 65'. Single-component King models in which mass follows light fail to reproduce the observed flatness of the velocity dispersion profile. Two-component (luminous plus dark matter) models can reproduce the data, provided that the dark component extends sufficiently beyond the luminous component and the central dark matter density is of the same order as the central luminous density. These requirements suggest a more massive, darker Fornax than standard core-fitting analyses have previously concluded, with M/LV over the sampled region reaching 10-40 times the M/LV of the luminous component. We also apply a nonparametric mass estimation technique, introduced in a companion paper. Although it is designed to operate on data sets containing velocities for >1000 stars, the estimation yields preliminary results suggesting M/LV ~ 15 inside r < 1.5 kpc.
Relationships of human plasma fluoride and bone fluoride to age.

Fluoride analyses were carried out on blood samples from fasting subjects and on iliac crest biopsies obtained at autopsy, using an ion-selective electrode. Correlation coefficients of 0.53 and 0.67 respectively were determined between plasma fluoride and age, and bone fluoride and age. The proportionate rates of increase of fluoride levels in plasma and bone with age and the similarity of the correlation coefficients suggest that the fasting plasma fluoride concentration is in equilibrium with bone fluoride.
Unilateral versus bilateral adnexal disease in stage III and stage IV endometriosis does not affect pregnancy outcome after operative laparoscopy

To study the effect of unilateral versus bilateral adnexal involvement on the pregnancy rate after operative laparoscopy. Historic cohort study. A total of 143 patients with advanced stages of endometriosis (stage III and IV) who underwent operative laparoscopy for infertility treatment were categorized into those with unilateral versus bilateral adnexal disease. Forty-three patients had primarily unilateral (group 1) and 100 had bilateral disease (group 2). Follow-up was up to 2 years. There was no significant difference between group 1 and group 2 with respect to pregnancy rates (28% vs 31%), delivery rates (21% vs 23%), miscarriage rates (25% vs 13%), and ectopic rates (0% vs 13%). Cumulative conception rates after up to 24 cycles of natural intercourse and up to three IUI cycles were 59% and 49% for group 1 and group 2, respectively. Operative laparoscopy for advanced stages of endometriosis appears to be an effective treatment modality for establishing a pregnancy in infertile patients. Pregnancy and delivery rates are not different in patients with unilateral or bilateral adnexal involvement.
How cyclobutanes are assembled in nature – insights from quantum chemistry

Biosynthetic production of cyclobutanes leads to many complex natural products. Recently, theoretical work employing quantum chemical calculations has shed light on many of the details of cyclobutane-formation, in particular, for terpene natural products. Specific insights and general principles derived from these theoretical studies are described herein.
Discovery of Multiple Molecular Shells in the Outer Envelope of IRC +10216

We present 12CO J = 1 → 0 maps of the extended envelope of IRC +10216 made by combining BIMA millimeter array and NRAO 12 m telescope observations. CO emission was detected beyond the radius of 140'', which traces the history of mass loss for the past ~7000 yr. We discover superposed on the CO envelope clumpy arcs of enhanced emission, circumscribing the star, at multiple radii ranging from about 26'' to 120''. The arcs are found to be coherent across a range of velocities, thus forming sections of multiple shells that are participating in the circumstellar expansion. The intershell timescales range from 1300 to 2900 yr, which are roughly consistent with simulations where wind modulations from a single thermal pulse event can lead to the formation of multiple shells. The multiple enhanced shells within the continuous envelope of IRC +10216 may be the high mass-loss rate counterpart to the detached shells detected around several low mass-loss rate carbon stars, such as TT Cyg.
High Q micro-ring resonators fabricated from polycrystalline aluminum nitride films for near infrared and visible photonics

We demonstrate wideband integrated photonic circuits in sputter-deposited aluminum nitride (AlN) thin films. At both near-infrared and visible wavelengths, we achieve low propagation loss in integrated waveguides and realize high-quality optical resonators. In the telecoms C-band (1520-1580 nm), we obtain the highest optical Q factor of 440,000. Critical coupled devices show extinction ratio above 30 dB. For visible wavelengths (around 770 nm), intrinsic quality factors in excess of 30,000 is demonstrated. Our work illustrates the potential of AlN as a low loss material for wideband optical applications.
Digital Restoration Of AC-Coupled Infrared Images

A simple digital recursion relation has been developed to restore images which have been degraded by the AC coupling characteristics of infrared imaging sensors. The recursion relation is derived and shown to be equivalent to inverse filtering. To indicate the magnitude of the distortion due to AC coupling the RMS deviation between input and output signals is calculated for a single rectangular pulse and a series of rectangular pulses. Examples of images before and after the recursive restoration process are shown.
A perspective on pentaquarks

Recent discoveries of manifestly exotic, narrow baryon resonances present a fundamental challenge for our theoretical understanding of low-energy QCD. This is a brief survey of their interpretation, emphasizing the possibility that diquark correlations are centrally involved. Many predictions and suggestions for future directions follow from that idea.
The Role of True Finiteness in the Admissible Recursively Enumerable Degrees

Introduction Coding into the R. E. degrees Coding effective successor models A negative result concerning effective successor models A nonembedding result Embedding the 1-3-1 lattice Appendix A. Basics Appendix B. The jump Appendix C. The projectum Appendix D. The admissible collapse Appendix E. Prompt permission Appendix. Bibliography.
Associations Between Practice-Reported Medical Homeness and Health Care Utilization Among Publicly Insured Children

Abstract Background The patient-centered medical home (PCMH) is widely promoted as a model to improve the quality of primary care and lead to more efficient use of health care services. Few studies have examined the relationship between PCMH implementation at the practice level and health care utilization by children. Existing studies show mixed results. Methods Using practice-reported PCMH assessments and Medicaid claims from child-serving practices in 3 states participating in the Children's Health Insurance Program Reauthorization Act of 2009 Quality Demonstration Grant Program, this study estimates the association between medical homeness (tertiles) and receipt of well-child care and nonurgent, preventable, or avoidable emergency department (ED) use. Multilevel logistic regression models are estimated on data from 32 practices in Illinois (IL) completing the National Committee for Quality Assurance's (NCQA) medical home self-assessment and 32 practices in North Carolina (NC) and South Carolina (SC) completing the Medical Home Index (MHI) or Medical Home Index—Revised Short Form (MHI-RSF). Results Medical homeness was not associated with receipt of age-appropriate well-child visits in either sample. Associations between nonurgent, preventable, or avoidable ED visits and medical homeness varied. No association was seen among practices in NC and SC that completed the MHI/MHI-RSF. Children in practices in IL with the highest tertile NCQA self-assessment scores were less likely to have a nonurgent, preventable, or avoidable ED visit than children in practices with low (odds ratio 0.65; 95% confidence interval 0.47–0.92; P P = .06). Conclusions Higher levels of medical homeness may be associated with lower nonurgent, preventable, or avoidable ED use by publicly insured children. Robust longitudinal studies using multiple measures of medical homeness are needed to confirm this observation.
Frequency-Tunable Josephson Junction Resonator for Quantum Computing

We have fabricated and measured a high-Q Josephson junction resonator with a tunable resonance frequency. A dc magnetic flux allows the resonance frequency to be changed by over 10%. Weak coupling to the environment allows a quality factor of ~7000 when on average less than one photon is stored in the resonator. At large photon numbers, the nonlinearity of the Josephson junction creates two stable oscillation states. This resonator can be used as a tool for investigating the quality of Josephson junctions in qubits below the single photon limit, and can be used as a microwave qubit readout at high photon numbers.
Rental housing and crime: the role of property ownership and management

This study examines how residential rental property ownership characteristics affect crime. It examines the incidence and frequency of disturbances, assaults, and drug possession and distribution using police incident report data for privately owned rental properties. Results show that a small percentage of rental properties generate incident reports. Count model regressions indicate that the distance the owner resides from the rental property, size of rental property holdings, tenant Section 8 voucher use, and neighborhood owner-occupied housing rates are associated with reported violations. The study concludes with recommendations about local government policies that could help to reduce crime in rental housing.
Neutrinos: A Glimpse beyond the standard model

After a review of the early history of neutrinos and their detection, we analyze the different types of models that extend the standard model to massive neutrinos. We emphasize the generic nature of maximal mixing between muon and tau neutrinos, given simple assumptions based on grand unification.
Orbits in Extended Mass Distributions: General Results and the Spirographic Approximation

This paper explores orbits in extended mass distributions and develops an analytic approximation scheme based on epicycloids (spirograph patterns). We focus on the Hernquist potential ψ = 1/(1 + ξ), which provides a good model for many astrophysical systems, including elliptical galaxies (with an R1/4 law), dark matter halos (where N-body simulations indicate a nearly universal density profile), and young embedded star clusters (with gas density ρ ~ ξ-1). For a given potential, one can readily calculate orbital solutions as a function of energy and angular momentum using numerical methods. In contrast, this paper presents a number of analytic results for the Hernquist potential and proves a series of general constraints showing that orbits have similar properties for any extended mass distribution (including, e.g., the NFW profile). We discuss circular orbits, radial orbits, zero-energy orbits, different definitions of eccentricity, analogs of Kepler's law, the definition of orbital elements, and the relation of these orbits to spirograph patterns (epicycloids). Over a large portion of parameter space, the orbits can be adequately described (with accuracy better than 10%) using the parametric equations of epicycloids, thereby providing an analytic description of the orbits. As an application of this formal development, we find a solution for the orbit of the Large Magellanic Cloud in the potential of our Galaxy.
Complex Organic Molecules at High Spatial Resolution toward ORION-KL. I. Spatial Scales

Here we present high spatial resolution (<1'') observations of molecular emission in Orion-KL conducted using the Combined Array for Research in Millimeter-wave Astronomy. This work was motivated by recent millimeter continuum imaging studies of this region conducted at a similarly high spatial resolution, which revealed that the bulk of the emission arises from numerous compact sources, rather than the larger-scale extended structures typically associated with the Orion Hot Core and Compact Ridge. Given that the spatial extent of molecular emission greatly affects the determination of molecular abundances, it is important to determine the true spatial scale for complex molecules in this region. Additionally, it has recently been suggested that the relative spatial distributions of complex molecules in a source might give insight into the chemical mechanisms that drive complex chemistry in star-forming regions. In order to begin to address these issues, this study seeks to determine the spatial distributions of ethyl cyanide [C{sub 2}H{sub 5}CN], dimethyl ether [(CH{sub 3}){sub 2}O], methyl formate [HCOOCH{sub 3}], formic acid [HCOOH], acetone [(CH{sub 3}){sub 2}CO], SiO, methanol [CH{sub 3}OH], and methyl cyanide [CH{sub 3}CN] in Orion-KL at {lambda} = 3 mm. We find that for all observed molecules, the molecular emission arises from multiplemore » components of the cloud that include a range of spatial scales and physical conditions. Here, we present the results of these observations and discuss the implications for studies of complex molecules in star-forming regions.« less
Specialization, factor accumulation and development

Abstract We estimate the effect of factor proportions on the pattern of manufacturing specialization in a cross-section of OECD countries, taking into account that factor accumulation responds to productivity. We show that the failure to control for productivity differences produces biased estimates. Our model explains 2/3 of the observed differences in the pattern of specialization between the poorest and richest OECD countries. However, because factor proportions and the pattern of specialization co-move in the development process, their strong empirical relationship is not sufficient to determine whether specialization is driven by factor proportions, or by other mechanisms also correlated with level of development.
Synthesis and biological activity of aldose reductase inhibitors with Michael acceptor substituents

Abstract Derivatives of alrestatin ( 1 – 5 ) and alconil ( 6 – 8 ) possessing Michael acceptor substituents were synthesized as aldose reductase inhibitors. The alrestatin derivatives demonstrated enhanced aldose reductase inhibitory activity. The most potent reversible inhibitor of the series (compound 3 ) was 15-fold more active than alrestatin. Additionally, lipophilic analogues of alrestatin selectively inhibited rat lens aldose reductase versus rat kidney aldehyde reductase. Unlike alrestatin derivatives, alconil derivatives with similar substituents did not demonstrate significant reversible or irreversible inhibition of aldose reductase.
Organic chemistry: Catalysis marches on

A fresh take on an established chemical reaction has solved a long-standing problem in organic synthesis: how to prepare single mirror-image isomers of groups known as isolated quaternary stereocentres. See Article p.340
Export Performance and Trade Facilitation Reform : Hard and Soft Infrastructure

Summary We estimate the impact of aggregate indicators of “soft” and “hard” infrastructure on the export performance of developing countries. We derive four new indicators for more than 100 countries over the period 2004–07. Estimates show that trade facilitation reforms do improve the export performance of developing countries. This is particularly true with investment in physical infrastructure and regulatory reform to improve the business environment. The findings provide evidence that the marginal effect of the transport efficiency and business environment improvement on exports appears to be decreasing in per capita income. In contrast, the impact of physical infrastructure and information and communications technology on exports appears increasingly important the richer a country becomes. We also find statistical evidence on the complementarity between hard infrastructure and soft infrastructure, as captured by our indicators. Finally, drawing on estimates, we compute illustrative ad-valorem equivalents of improving each indicator halfway to the level of the top performer in the region.
Geometric characterizations of the representation type of hereditary algebras and of canonical algebras

Abstract We show that a finite connected quiver Q with no oriented cycles is tame if and only if for each dimension vector d and each integral weight θ of Q, the moduli space M ( Q , d ) θ s s of θ-semi-stable d-dimensional representations of Q is just a projective space. In order to prove this, we show that the tame quivers are precisely those whose weight spaces of semi-invariants satisfy a certain log-concavity property. Furthermore, we characterize the tame quivers as being those quivers Q with the property that for each Schur root d of Q, the field of rational invariants k ( rep ( Q , d ) ) GL ( d ) is isomorphic to k or k ( t ) . Next, we extend this latter description to canonical algebras. More precisely, we show that a canonical algebra Λ is tame if and only if for each generic root d of Λ and each indecomposable irreducible component C of rep ( Λ , d ) , the field of rational invariants k ( C ) GL ( d ) is isomorphic to k or k ( t ) . Along the way, we establish a general reduction technique for studying fields of rational invariants on Schur irreducible components of representation varieties.