cssi/SciSciGPT-SciSciNet huggingface dataset:
New Results in t-Tone Coloring of Graphs

A $t$-tone $k$-coloring of $G$ assigns to each vertex of $G$ a set of $t$ colors from $\{1,\dots,k\}$ so that vertices at distance $d$ share fewer than $d$ common colors. The $t$-tone chromatic number of $G$, denoted $ t (G)$, is the minimum $k$ such that $G$ has a $t$-tone $k$-coloring. Bickle and Phillips showed that always $\tau_ 2 (G) \leq [\Delta(G)]^2 +\Delta(G)$, but conjectured that in fact $\tau_ 2 (G) \leq 2\Delta(G) + 2$; we confirm this conjecture when $\Delta(G) \leq 3$ and also show that always $\tau_ 2 (G) \leq \lceil (2 +\sqrt{2}) \Delta(G) \rceil$. For general $t$ we prove that $\tau_ t (G) \leq (t^ 2 +t) \Delta(G)$. Finally, for each $t \geq 2$ we show that there exist constants $c_ 1$ and $c_ 2$ such that for every tree $T$ we have $c_ 1 \sqrt{\Delta(T)} \leq \tau_t(T) \leq c_2\sqrt{\Delta(T)}$.
The Latest Misfires in Support of the More Guns, Less Crime Hypothesis

IN TROD UCT ION 1371 I. THE DATA STRONGLY REJECT AGGREGATE SPECIFICATIONS 1374 II. THE DISAGGREGATED REGRESSIONS SHOW THAT CONCEALED-CARRY LAWS TEND TO INCREASE CRIME 1388 III. THE PW REGRESSIONS ON THE NEW COUNTY DATASET ARE ALL FATALLY FLAWED BY SERIOUS CODING PROBLEMS 1392 C O N CLU SIO N 1395
Family‐based association for quantitative traits.

Tests of allelic association are designed to demonstrate relationships between genetic and phenotypic information. The class of tests using transmission information from parents to offspring (TDT and its generalizations) are very popular with dichotomous phenotypes because of their lack of sensitivity to population heterogeneity. Here we discuss the generalization of this approach to quantitative phenotypes.
The complexity of stoquastic local Hamiltonian problems

We study the complexity of the Local Hamiltonian Problem (denoted as LH-MIN) in the special case when a Hamiltonian obeys the condition that all off-diagonal matrix elements in the standard basis are real and non-positive. We will call such Hamiltonians, which are common in the natural world, stoquastic. An equivalent characterization of stoquastic Hamiltonians is that they have an entry-wise non-negative Gibbs density matrix for any temperature. We prove that LH-MIN for stoquastic Hamiltonians belongs to the complexity class AM -- a probabilistic version of NP with two rounds of communication between the prover and the verifier. We also show that 2-local stoquastic LH-MIN is hard for the class MA. With the additional promise of having a polynomial spectral gap, we show that stoquastic LH-MIN belongs to the class PostBPP=BPPpath--a generalization of BPP in which a post-selective readout is allowed. This last result also shows that any problem solved by adiabatic quantum computation using stoquastic Hamiltonians is in PostBPP.
The Three-Body Problem and the Shape Sphere

The three-body problem defines dynamics on the space of triangles in the plane. The shape sphere is the moduli space of oriented similarity classes of planar triangles and lies inside shape space, a Euclidean three-space parameterizing oriented congruence classes of triangles. We derive and investigate the geometry and dynamics induced on these spaces by the three-body problem. We present two theorems concerning the three-body problem whose discovery was made through the shape space perspective. 1. INTRODUCTION. In 1667 Newton (21) posed the three-body problem. Central questions within the problem remain open today despite penetrating work over the centuries by many of our most celebrated mathematicians, including Euler, Lagrange, Laplace, Legendre, d'Alembert, Clairaut, Delanay, Poincare, Birkhoff, Seigel, Kol- mogorov, Arnol'd, Moser, and Smale. The problem, in its crudest form, asks us to solve the system of Ordinary Differ- ential Equations (ODEs), Equations (1), governing the motion of three point masses moving in space under the sole influence of each other's mutual gravitational attrac- tions. The masses form the vertices of a triangle, so we can think of the problem as one of moving triangles. According to the relativity principle of Galilieo, the laws of physics are invariant under isometries. Isometries are the congruences of Euclid. Two triangles are congruent if and only if the lengths of their three sides are equal. Is there a system of second order ODEs in the lengths of the three sides that describes the three-body problem? All attempts to write down such a system of ODEs break down at collinear triangles. Instead, we will derive three alternative variables to the side lengths of a triangle and show that there is such a system of ODEs in these variables. Unlike the side lengths, the alternative variables are not invariant under all congruences but, rather, only un- der "oriented congruences." Two triangles are "oriented congruent" if a composition of a translation and rotation takes one to the other. Oriented congruence excludes re- flections. We define shape space to be the space of oriented congruence classes of planar triangles. Shape space is homeomorphic to R 3 and is parameterized by the vec- tor (w1 ,w 2 ,w 3) formed by these three alternative variables. We derive second order ODEs (Equation (54)) for these alternative variables that encode a special case of the three-body problem. Shape space is homeomorphic to R 3 but it is not isometric to R 3 . The shape space metric is not Euclidean. Nevertheless the shape space metric does enjoy spherical sym- metry, which means that at the heart of shape space geometry is a two-dimensional sphere. We call this sphere the shape sphere. Its points represent oriented similarity classes of planar triangles (Figure 2). The purpose of this article is to describe the ge- ometry of this sphere, how it relates to the three-body problem, and how this relation yields new insights into this age-old problem.
Role of splenectomy in chronic lymphocytic leukemia.

Abstract Background: The benefit of splenectomy, performed for complications of chronic lymphocytic leukemia (CLL) including autoimmune hemolytic anemia, thrombocytopenia, hypersplenism, and symptomatic splenomegaly, has not been clearly demonstrated. The objective of this study was to determine if splenectomy achieves a predictable hematologic and survival advantage over conventional chemotherapy in patients with CLL. Study Design: A retrospective review was performed of 77 consecutive patients with CLL who underwent splenectomy between 1970 and 1994 at the University of Texas M D Anderson Cancer Center. Indications for splenectomy, pre- and postoperative hematologic profiles, response to splenectomy, and time to progression and death were recorded. Kaplan-Meier life tables were constructed, and a comparison to an age- and gender-matched cohort of CLL patients treated with fludarabine and no splenectomy was performed using log rank statistical analysis. Results: Seventy-six percent of the patients studied were Rai stage III/IV. Twenty of 29 patients with hemoglobin counts (Hb) ≤ 10 g/dL and 11 of 18 patients with platelet counts (plt) 9 /L achieved an excellent hematologic response to splenectomy. Splenectomy significantly improved survival in patients with Hb ≤ 10 g/dL or plt ≤ 50 × 10 9 /L (p = 0.025). Thrombocytopenia did not significantly increase postoperative morbidity, and mortality rate was not significantly different between treatment groups. Conclusions: Splenectomy significantly improves survival in selected subgroups of patients with advanced-stage CLL over that achieved with conventional chemotherapy. Based on these results, splenectomy should be performed early in the course of the disease in CLL patients with either an Hb ≤ 10 g/dL or plt ≤ 50 × 10 9 /L.
Shocking Behavior: Random Wealth in Antebellum Georgia and Human Capital Across Generations

Does the lack of wealth constrain parents' investments in the human capital of their descendants? We conduct a nearly fifty-year followup of an episode in which such constraints would have been plausibly relaxed by a random allocation of substantial wealth to families. We track descendants of participants in Georgia's Cherokee Land Lottery of 1832, in which nearly every adult white male in Georgia took part. Winners received close to the median level of wealth - a large financial windfall orthogonal to participants' underlying characteristics that might have also affected their children's human capital. Although winners had slightly more children than non-winners, they did not send them to school more. Sons of winners have no better adult outcomes (wealth, income, literacy) than the sons of non-winners, and winners' grandchildren do not have higher literacy or school attendance than non-winners' grandchildren. This suggests only a limited role for family financial resources in the formation of human capital in the next generations in this environment and a potentially more important role for other factors that persist through family lines.
Robust Adaptive Control

The paper addresses an open problem concerned with the boundedness of signals in an adaptive loop when external perturbations are present. A complete solution is provided for the case of a first order plant with an unknown parameter by analyzing a nonlinear differential equation in R2. It is shown that if the persistent excitation of the reference input is larger than the perturbation in some sense, the solutions will be globally bounded. The same methodology appears to be applicable to the general adaptive control problem.
Measuring the hardness of stochastic sampling on Bayesian networks with deterministic causalities: the k -Test

Approximate Bayesian inference is NP-hard. Dagum and Luby defined the Local Variance Bound (LVB) to measure the approximation hardness of Bayesian inference on Bayesian networks, assuming the networks model strictly positive joint probability distributions, i.e. zero probabilities are not permitted. This paper introduces the k-test to measure the approximation hardness of inference on Bayesian networks with deterministic causalities in the probability distribution, i.e. when zero conditional probabilities are permitted. Approximation by stochastic sampling is a widely-used inference method that is known to suffer from inefficiencies due to sample rejection. The k-test predicts when rejection rates of stochastic sampling a Bayesian network will be low, modest, high, or when sampling is intractable.
Promotion and Evacuation

Promotion and evacuation are bijections on the set of linear extensions of a finite poset first defined by Schutzenberger. This paper surveys the basic properties of these two operations and discusses some generalizations. Linear extensions of a finite poset $P$ may be regarded as maximal chains in the lattice $J(P)$ of order ideals of $P$. The generalizations concern permutations of the maximal chains of a wider class of posets, or more generally bijective linear transformations on the vector space with basis consisting of the maximal chains of any poset. When the poset is the lattice of subspaces of ${\Bbb F}_q^n$, then the results can be stated in terms of the expansion of certain Hecke algebra products.
On the Andrews-Stanley refinement of Ramanujan’s partition congruence modulo 5 and generalizations

In a recent study of sign-balanced, labelled posets, Stanley introduced a new integral partition statistic srank(π) = O(π) - O(π'), where O(π) denotes the number of odd parts of the partition π and π' is the conjugate of π. In a forthcoming paper, Andrews proved the following refinement of Ramanujan's partition congruence mod 5: p 0 (5n + 4) ≡ p 2 (5n + 4) ≡ 0 (mod 5), p(n) = p 0 (n) + p 2 (n), where p i (n) (i = 0,2) denotes the number of partitions of n with srank ≡ i (mod 4) and p(n) is the number of unrestricted partitions of n. Andrews asked for a partition statistic that would divide the partitions enumerated by p i (5n + 4) (i = 0, 2) into five equinumerous classes. In this paper we discuss three such statistics: the ST-crank, the 2-quotient-rank and the 5-core-crank. The first one, while new, is intimately related to the Andrews-Garvan (1988) crank. The second one is in terms of the 2-quotient of a partition. The third one was introduced by Garvan, Kim and Stanton in 1990. We use it in our combinatorial proof of the Andrews refinement. Remarkably, the Andrews result is a simple consequence of a stronger refinement of Ramanujan's congruence mod 5. This more general refinement uses a new partition statistic which we term the BG-rank. We employ the BG-rank to prove new partition congruences modulo 5. Finally, we discuss some new formulas for partitions that are 5-cores and discuss an intriguing relation between 3-cores and the Andrews-Garvan crank.
Inferring anthropogenic trends from satellite data for water-sustainability of US cities near artificial reservoirs

Abstract Anthropogenic activities affect the water cycle and water supply at global and regional spatial scales, and approaches to water management must consider anthropogenic inputs. One of the major inputs in local-to-regional availability of water and the water cycle is land use land cover change as a result of urbanization, artificial reservoirs, and irrigation activity. To understand evolving trends in local hydrologic cycle for water sustainability of growing cities, this study employed a multi-factorial approach involving population trends, water use (and demand), streamflow, and various satellite-derived water-relevant variables. These variables are daily precipitation (from Tropical Rainfall Measuring Mission-TRMM, 3B42.V7), Normalized Difference Vegetation Index (NDVI) (from Moderate Resolution Imaging Spectroradiometer-MODIS-MOD13A1), land surface temperature (LST) (from MODIS-MOD11A2), and land cover (MODIS-MCD12Q1). Long term trends in such data were used to understand temporal and spatial trends in impounded watersheds hosting a large and growing city. The cities studied for water sustainability were Atlanta, Georgia and Buford dam; Columbia, South Carolina and Saluda dam; Columbus, Ohio and Alum Creek dam; Montgomery, Alabama and Jordan dam; Tulsa, Oklahoma and Keystone dam; and Tuscaloosa, Alabama and Tuscaloosa dam. Our study reveals that daily mean stream flow has been decreasing in all but one (Tulsa) of the areas selected. Satellite data trends between 2000 and 2012 showed a steady decrease in precipitation and NDVI, while LST has gradually increased. We attribute the NDVI (i.e., gradual decrease in vegetation cover) to LST rather than precipitation trends. The results of this research suggest that future temperature projections from climate models can be used in understanding vegetation activity and water availability over the study areas. Cities with larger upstream watershed area are potentially more sustainable and resilient (than those with small watersheds) as a result of spatial variability of water resources' response to climate change. Inter-basin water resources transfer is a possible solution to vulnerable cities in the future. The study results also emphasize the need to establish a sustainable and resilient water resources management system that includes narrowing the information and perception gap between the engineering community and the general public.
Regional Financial Market Integration: Learning from the European Experience

The so-called "European model" of market integration has evolved over many decades. In particular, the original plan to integrate Europe economically via a progressive program of harmonizing national legislation has, particularly in the area of financial markets, given way to a radical alternative based upon Member State "mutual recognition" of existing national legislation and regulation. Whereas this shift had been initiated largely on pragmatic grounds, the mutual recognition approach has since taken on an ideological and strategic dimension in political negotiations which makes the study of its effects on the ground all the more important.
Some classes of minimally almost periodic topological groups

A Hausdorff topological group G=(G,T) has the small subgroup generating property (briefly: has the SSGP property, or is an SSGP group) if for each neighborhood U of $1_G$ there is a family $\sH$ of subgroups of $G$ such that $\bigcup\sH\subseteq U$ and $\langle\bigcup\sH\rangle$ is dense in $G$. The class of \rm{SSGP}$ groups is defined and investigated with respect to the properties usually studied by topologists (products, quotients, passage to dense subgroups, and the like), and with respect to the familiar class of minimally almost periodic groups (the m.a.p. groups). Additional classes SSGP(n) for $n<\omega$ (with SSGP(1) = SSGP) are defined and investigated, and the class-theoretic inclusions $$\mathrm{SSGP}(n)\subseteq\mathrm{SSGP}(n+1)\subseteq\mathrm{ m.a.p.}$$ are established and shown proper. In passing the authors also establish the presence of {\rm SSGP}$(1)$ or {\rm SSGP}$(2)$ in many of the early examples in the literature of abelian m.a.p. groups.
Phosphine-Catalyzed Doubly Stereoconvergent γ-Additions of Racemic Heterocycles to Racemic Allenoates: The Catalytic Enantioselective Synthesis of Protected α,α-Disubstituted α-Amino Acid Derivatives

Methods have recently been developed for the phosphine-catalyzed asymmetric γ-addition of nucleophiles to readily available allenoates and alkynoates to generate useful α,β-unsaturated carbonyl compounds that bear a stereogenic center in either the γ or the δ position (but not both) with high stereoselectivity. The utility of this approach would be enhanced considerably if the stereochemistry at both termini of the new bond could be controlled effectively. In this report, we describe the achievement of this objective, specifically, that a chiral phosphepine can catalyze the stereoconvergent γ-addition of a racemic nucleophile to a racemic electrophile; through the choice of an appropriate heterocycle as the nucleophilic partner, this new method enables the synthesis of protected α,α-disubstituted α-amino acid derivatives in good yield, diastereoselectivity, and enantioselectivity.
Using design metrics for predicting system flexibility

While multiagent systems have been extolled as dynamically configurable and capable of emergent behavior, these qualities can be a drawback. When the system changes so that it no longer achieves its goals, emergent behavior is undesirable. Giving agents the autonomy to adapt and then expecting them to adapt only in acceptable ways requires rigorous design analyses. In this paper, we propose metrics for determining system flexibility at design time. Our approach is based on organization-based multiagent systems, which allows multiagent systems to adapt within a preset structure. We tailored the Bogor model checker to efficiently analyze the adaptive behaviors of these systems and to determine their properties such as fault-tolerance and cost-efficiency. We develop state-space coverage metrics to allow designers to make informed trade-offs at design-time between computational cost and system flexibility.
Flattening Firms and Wage Distribution

This chapter studies the consequences of firm delayering on wages and the wage distribution inside firms. I consider a market-based tournament model with asymmetric information to endogenize firms’ delayering decisions. My model predicts that when the CEO becomes more productive, firms grow in size. When the CEO becomes sufficiently productive, firms delayer. After delayering, wages at all levels rise and the wage gap between the CEO and the laborers widens. These predictions capture the dynamic process of firms’ structure and size changes and match a set of empirical findings in recent studies that are not well explained by existing theories.
Torsion-free, Divisible, and Mittag-Leffler Modules

We study (relative) &#x1d4a6;-Mittag–Leffler modules, with emphasis on the class &#x1d4a6; of absolutely pure modules. A final goal is to describe the &#x1d4a6;-Mittag–Leffler abelian groups as those that are, modulo their torsion part, ℵ1-free. Several more general results of independent interest are derived on the way. In particular, every flat &#x1d4a6;-Mittag–Leffler module (for &#x1d4a6; as before) is Mittag–Leffler. A question about the definable subcategories generated by the divisible modules and the torsion-free modules, resp., has been left open.
Wearable Conductive Fiber Sensors for Multi-Axis Human Joint Angle Measurements

BACKGROUND: The practice of continuous, long-term monitoring of human joint motion is one that finds many applications, especially in the medical and rehabilitation fields. There is a lack of acceptable devices available to perform such measurements in the field in a reliable and non-intrusive way over a long period of time. The purpose of this study was therefore to develop such a wearable joint monitoring sensor capable of continuous, day-to-day monitoring. METHODS: A novel technique of incorporating conductive fibers into flexible, skin-tight fabrics surrounding a joint is developed. Resistance changes across these conductive fibers are measured, and directly related to specific single or multi-axis joint angles through the use of a non-linear predictor after an initial, one-time calibration. Because these sensors are intended for multiple uses, an automated registration algorithm has been devised using a sensitivity template matched to an array of sensors spanning the joints of interest. In this way, a sensor array can be taken off and put back on an individual for multiple uses, with the sensors automatically calibrating themselves each time. RESULTS: The wearable sensors designed are comfortable, and acceptable for long-term wear in everyday settings. Results have shown the feasibility of this type of sensor, with accurate measurements of joint motion for both a single-axis knee joint and a double axis hip joint when compared to a standard goniometer used to measure joint angles. Self-registration of the sensors was found to be possible with only a few simple motions by the patient. CONCLUSION: After preliminary experiments involving a pants sensing garment for lower body monitoring, it has been seen that this methodology is effective for monitoring joint motion of the hip and knee. This design therefore produces a robust, comfortable, truly wearable joint monitoring device.
Export Variety and Country Productivity

The authors study the link between export product variety and country productivity based on data from 34 industrial and developing countries, from 1982 to 1997. They measure export product variety by the share of U.S. imports on the set of goods exported by each sampled country relative to the world. It is a theoretically sound index which is consistent with within-country GDP maximization, as well as cross-country comparison. They construct country productivity based on relative endowments and product variety. Increases in output product variety improve country productivity as the new mix of output may better use resources of the economy, and improve allocation efficiency. Such effects depend on the elasticity of substitution in production between the different varieties. The more different the varieties are in terms of production, the more efficient it is to use the endowments of the economy when a new variety is available, which leads to productivity gains. In addition, as suggested in the literature, export product variety depends on trade costs, such as tariffs, distance, and transport costs. Such trade cost variables are used as instruments to help the authors identify the effects of export variety on country productivity. Empirical evidence supports their hypothesis. Overall, while export variety accounts for only 2 percent of cross-country productivity differences, it explains 13 percent of within-country productivity growth. A 10 percent increase in the export variety of all industries leads to a 1.3 percent increase in country productivity, while a 10 percentage point increase in tariffs facing an exporting country leads to a 2 percent fall in country productivity.
Chains in weak order posets associated to involutions

The W -set of an element of a weak order poset is useful in the cohomological study of the closures of spherical subgroups in generalized flag varieties. We explicitly describe in a purely combinatorial manner the W -sets of three different weak order posets: the set of all involutions in the symmetric group, the set of fixed point free involutions of the symmetric group, and the set of charged involutions. These distinguished sets of involutions parametrize Borel orbits in the classical symmetric spaces associated to the general linear group. In particular, we characterize the maximal chains of an arbitrary lower order ideal in any of these three posets.
Iron, Copper and Zinc Metabolism of Rats Fed Various Levels and Types of Tea

The effects of tea and components in tea on mineral metabolism were investigated in a series of studies. In studies A and B weanling rats were fed diets containing various levels (0, 0.35, 1.17 or 3.50%) of a commercially prepared instant tea and diets containing 0 or 1.17% catechin. In study C anemic rats were fed diets containing 0 or 2.31% desiccated green or black tea infusions for 23 d. In study D rats were fed a diet containing 2.31% desiccated black tea infusions for 16 d, were fed the tea-containing diet in a single meal labeled with 59Fe or were given black tea infusions as their sole fluids. Rats fed diets containing 2.31% green or black tea or given fluid tea had elevated hematocrits but experienced minimal changes in tissue iron levels or in iron absorption; this is counter to conclusions from studies in which iron absorption was monitored indirectly. Ingestion of instant or black tea consistently elevated liver copper levels; this may be part of the mechanism by which hematological variables were affected. Although the green tea contained significant amounts of aluminum, rats fed the tea did not accumulate aluminum in their bones.
Parameter spaces for curves on surfaces and enumeration of rational curves

Let S be a smooth, minimal rational surface. The geometry of the Severi variety parametrising irreducible, rational curves in a given linear system on S is studied. The results obtained are applied to enumerative geometry, in combination with ideas from Quantum Cohomology. Formulas enumerating rational curves are found, some of which generalised Kontsevich's formula for plane curves.
A universal symmetry detection algorithm

Research on symmetry detection focuses on identifying and detecting new types of symmetry. The paper presents an algorithm that is capable of detecting any type of permutation-based symmetry, including many types for which there are no existing algorithms. General symmetry detection is library-based, but symmetries that can be parameterized, (i.e. total, partial, rotational, and dihedral symmetry), can be detected without using libraries. In many cases it is faster than existing techniques. Furthermore, it is simpler than most existing techniques, and can easily be incorporated into existing software. The algorithm can also be used with virtually any type of matrix-based symmetry, including conjugate symmetry.
Excess Dietary Protein May Not Adversely Affect Bone

Too little protein is always harmful for the skeleton. Increasing dietary protein increases endogenous calcium excretion. The ability to adapt depends upon the adequacy of an individual's calcium intake. At a population level, the effect of protein is often minimized because calcium intake rises with increasing protein intake. A dietary calcium-to-protein ratio >/=20:1 (mg:g) probably provides adequate protection for the skeleton. Excess protein will not harm the skeleton if the calcium intake is adequate.
High-temperature stability and grain boundary complexion formation in a nanocrystalline Cu-Zr alloy

Nanocrystalline Cu-3 at.% Zr powders with ~20 nm average grain size were created with mechanical alloying and their thermal stability was studied from 550–950°C. Annealing drove Zr segregation to the grain boundaries, which led to the formation of amorphous intergranular complexions at higher temperatures. Grain growth was retarded significantly, with 1 week of annealing at 950°C, or 98% of the solidus temperature, only leading to coarsening of the average grain size to 54 nm. The enhanced thermal stability can be connected to both a reduction in grain boundary energy with doping as well as the precipitation of ZrC particles. High mechanical strength is retained even after these aggressive heat treatments, showing that complexion engineering may be a viable path toward the fabrication of bulk nanostructured materials with excellent properties.
Postoperative Surveillance and Long-term Outcomes After Endovascular Aneurysm Repair Among Medicare Beneficiaries.

Importance The Society for Vascular Surgery recommends annual surveillance with computed tomography (CT) or ultrasonography after endovascular aortic aneurysm repair (EVAR) for abdominal aortic aneurysms. However, such lifelong surveillance may be unnecessary for most patients, thereby contributing to overuse of imaging services. Objective To investigate whether nonadherence to Society for Vascular Surgery–recommended surveillance guidelines worsens long-term outcomes after EVAR among Medicare beneficiaries. Design, Setting, and Participants We collected data from Medicare claims from January 1, 2002, through December 31, 2011. A total of 9503 patients covered by fee-for-service Medicare who underwent EVAR from January 1, 2002, through December 31, 2005, were categorized as receiving complete or incomplete surveillance. We performed logistic regressions controlling for patient demographic and hospital characteristics. Patients were then matched by propensity score with adjusting for all demographic variables, including age, sex, race, Medicaid eligibility, residential status, hospital volume, ruptured abdominal aortic aneurysms, and all preexisting comorbidities. We then calculated differences in long-term outcomes after EVAR between adjusted groups. Data analysis was performed from January 1, 2002, through December 31, 2011. Main Outcomes and Measures Post-EVAR imaging modality, aneurysm-related mortality, late rupture, and complications. Results Median follow-up duration was 6.1 years. Incomplete surveillance was observed in 5526 of 9695 patients (57.0%) who survived the initial hospital stay at a mean (SD) of 5.2 (2.9) years after EVAR. After propensity matching, our cohort consisted of 7888 patients, among whom 3944 (50.0%) had incomplete surveillance. For those in the matched cohort, patients with incomplete surveillance had a lower incidence of late ruptures (26 of 3944 [0.7%] vs 57 of 3944 [1.4%]; P = .001) and major or minor reinterventions (46 of 3944 [1.2%] vs 246 of 3944 [6.2%]; P P = .07). In adjusted analysis of postoperative outcomes controlling for all patient and hospital factors by the tenth postoperative year, patients in the incomplete surveillance group experienced lower rates of total complications (2.1% vs 14.0%; P P P P P Conclusions and Relevance Nonadherence to the Society for Vascular Surgery guidelines for post-EVAR imaging was not associated with poor outcomes, suggesting that, in many patients, less frequent surveillance is not associated with worse outcomes. Improved criteria for defining optimal surveillance will achieve higher value in aneurysm care.
Bile Acids Conjugation in Human Bile Is Not Random: New Insights from 1H-NMR Spectroscopy at 800 MHz

Bile acids constitute a group of structurally closely related molecules and represent the most abundant constituents of human bile. Investigations of bile acids have garnered increased interest owing to their recently discovered additional biological functions including their role as signaling molecules that govern glucose, fat and energy metabolism. Recent NMR methodological developments have enabled single-step analysis of several highly abundant and common glycine- and taurine- conjugated bile acids, such as glycocholic acid, glycodeoxycholic acid, glycochenodeoxycholic acid, taurocholic acid, taurodeoxycholic acid, and taurochenodeoxycholic acid. Investigation of these conjugated bile acids in human bile employing high field (800 MHz) (1)H-NMR spectroscopy reveals that the ratios between two glycine-conjugated bile acids and their taurine counterparts correlate positively (R2 = 0.83-0.97; p = 0.001 x 10(-2)-0.006 x 10(-7)) as do the ratios between a glycine-conjugated bile acid and its taurine counterpart (R2 = 0.92-0.95; p = 0.004 x 10(-3)-0.002 x 10(-10)). Using such correlations, concentration of individual bile acids in each sample could be predicted in good agreement with the experimentally determined values. These insights into the pattern of bile acid conjugation in human bile between glycine and taurine promise useful clues to the mechanism of bile acids' biosynthesis, conjugation and enterohepatic circulation, and may improve our understanding of the role of individual conjugated bile acids in health and disease.
Aerodynamic Analysis of Multistage Turbomachinery Flows in Support of Aerodynamic Design

This paper summarizes the state of 3D CFD based models of the time average flow field within axial flow multistage turbomachines. Emphasis is placed on models which are compatible with the industrial design environment and those models which offer the potential of providing credible results at both design and off-design operating conditions. The need to develop models which are free of aerodynamic input from semi-empirical design systems is stressed. The accuracy of such models is shown to be dependent upon their ability to account for the unsteady flow environment in multistage turbomachinery. The relevant flow physics associated with some of the unsteady flow processes present in axial flow multistage machinery are presented along with procedures which can be used to account for them in 3D CFD simulations. Sample results are presented for both axial flow compressors and axial flow turbines which help to illustrate the enhanced predictive capabilities afforded by including these procedures in 3D CFD simulations. Finally, suggestions are given for future work on the development of time average flow models.
DUST GRAIN EVOLUTION IN SPATIALLY RESOLVED T TAURI BINARIES

Core-accretion planet formation begins in protoplanetary disks with the growth of small, interstellar medium dust grains into larger particles. The progress of grain growth, which can be quantified using 10 {mu}m silicate spectroscopy, has broad implications for the final products of planet formation. Previous studies have attempted to correlate stellar and disk properties with the 10 {mu}m silicate feature in an effort to determine which stars are efficient at grain growth. Thus far there does not appear to be a dominant correlated parameter. In this paper, we use spatially resolved adaptive optics spectroscopy of nine T Tauri binaries as tight as 0.''25 to determine if basic properties shared between binary stars, such as age, composition, and formation history, have an effect on dust grain evolution. We find with 90%-95% confidence that the silicate feature equivalent widths of binaries are more similar than those of randomly paired single stars, implying that shared properties do play an important role in dust grain evolution. At lower statistical significance, we find with 82% confidence that the secondary has a more prominent silicate emission feature (i.e., smaller grains) than the primary. If confirmed by larger surveys, this would imply that spectral type and/or binarity aremore » important factors in dust grain evolution.« less
Structural Analysis of a Parawing during Deployment

Finite element analysis of critical stress distribution in canopy of deployed twin keel parawing, predicting failure stress levels
Hydrogen diffusion in β-LaNi5 hydride

Abstract The coefficient of self-diffusion D of hydrogen in LaNi5H6.5 was measured in the temperature range 331 K ⩽ T ⩽ 375 K using a modified pulsed field gradient nuclear magnetic resonance (NMR) technique. The NMR relaxation times T1 and T1ρ were also measured in the temperature range 77 K ⩽ T ⩽ 375 K. D was found to follow the Arrhenius relation D = (0.14 cm 2 s −1 ) exp [{−40 kJ ( g atom H ) −1 RT} ] The activation energy EA of 40 kJ (g atom H)−1 determined from direct D measurements agrees well with EA determined from the slope of the short correlation time side of the T1ρ minimum. The observed T1 (60 MHz) and T1ρ (45 kHz) minima also scale according to an activation energy of 40 kJ (g atom H)−1. The long correlation time sides of both T1ρ and T1, however, indicate an activation energy for hydrogen motion of approximately 20 kJ (g atom H)−1. T1 was also found to contain contributions from the conduction electron relaxation mechanism (T1ET = 28.3 s K). The results of direct D measurements and of relaxation time measurements are shown to be consistent and are crudely interpreted in terms of a diffusion process involving more than one activation energy. The effects of LaNi5 surface segregation (to La2O3 and nickel) on the NMR relaxation time measurements are also discussed.
A Framework for Reduced Order Modeling with Mixed Moment Matching and Peak Error Objectives

We examine a new method of producing reduced order models for LTI systems which attempts to minimize a bound on the peak error between the original and reduced order models subject to a bound on the peak value of the input. The method, which can be implemented by solving a set of linear programming problems that are parameterized via a single scalar quantity, is able to minimize an error bound subject to a number of moment matching constraints. Moreover, because all optimization is performed in the time domain, the method can also be used to perform model reduction for infinite dimensional systems, rather than being restricted to finite order state space descriptions. We begin by contrasting the method we present here with two classes of standard model reduction algorithms, namely, moment matching algorithms and singular value-based methods. After motivating the class of reduction tools we propose, we describe the algorithm (which minimizes the $L_1$ norm of the difference between the original and reduced order impulse responses) and formulate the corresponding linear programming problem that is solved during each iteration of the algorithm. We then prove that, for a certain class of LTI systems, the method we propose can be used to produce reduced order models of arbitrary accuracy even when the original system is infinite dimensional. We then show how to incorporate moment matching constraints into the basic error bound minimization algorithm, and present three examples which utilize the techniques described herein. We conclude with some comments on extensions to multi-input, multi-output systems, as well as some general comments for future work.
Effects of MeV Ions on PE and PVDC

Abstract We studied the effects of 3.5 and 5.0 MeV alpha bombardment on polyethylene and polyvinylidene chloride, both of which have simple chemical structures. Using a thin polymer film stacking technique, we were able to map the effects of the MeV alpha particles in their track. The first layer of the thin polymer film stack experienced mostly the effects of the electronic energy deposited, and the last layer received mostly effects of the nuclear stopping. Using Raman microprobe analysis and by measuring the ratio of the formation of graphene structures (G-line) to the disordered (amorphous) carbon line (D-line), we were able to separate the severed bond effects at the end of the alpha particle tracks in the last polymer film layers from the effects of the electronic energy deposited in the first polymer film layers. The results are in agreement with our other measurements of each polymer film using FTIR, RBS and resistance measurements.
Flight Operations in the New Millennium

New approaches are being studied for real-time interaction, and related supporting processes, with spacecraft and instruments in deep-space. Spacecraft are evolving, improving in many ways, and generally, becoming more robust. Operations are changing also. Operations will be more automated in the future. However, there is a challenge. Deep-space missions are not all alike. The Operations phases of discovery and exploration are an extension of the research that creates the mission; they are the time of obtaining results. This examines the historical role of flight operations, and its evolving processes, to develop an understanding of the operational methods that will be effective in the future. It takes people, equipment, software, space, and connectivity for Operations success. A balance has to be struck between improving technology, gaining knowledge, automation, and realistic expectations. Finally, the recommended methods to gain efficiency in Operations are system-wide services and shared resources. These common processes will meet the challenge of varied missions.
Preparation and crystal and molecular structures of uranyl complexes of 4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione and the pyrazol-3-one analogue

Abstract Uranyl complexes of the ligands 4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione (Hbmppt), the 3-one analogue (Hbmpp), and the corresponding anions were prepared and characterized by elemental analysis and spectroscopic methods. The complexes UO2(NO3)2(Hbmppt)· acetone and UO2(NO3)2(Hbmpp)·acetone can be isolated from the reaction of UO2(NO3)2·6H2O and Hbmppt for Hbmpp in acetone. In ethanol, UO2(NO3)2·6H2O reacts with K(bmppt) or Hbmpp to give UO2(bmppt)2·2EtOH or UO2(bmpp)2· 2EtOH, respectively. The ethanol adducts will react with dimethylsulfoxide to yield the dmso complexes UO2(bmppt)2(dmso)·acetone and UO2(bmpp)2(dmso). UO2(NO3)2(Hbmmppt)·acetone crystallizes in the triclinic space group P l with a = 9.663(5), b = 11.522(4), c = 11.823(3) A, α = 78.18(3), β = 72.56(3), γ = 76.54(4)°, Z = 2, V = 1208.3 A3, pcalc = 2.05 g cm−3, RF = 0.031, RwF = 0.038. The crystal structure shows two bidentate nitrate anions and a neutral bidentate Hbmppt ligand (US = 2.871(3) A) in the equational plane of the UO22+ ion. The Hbmppt ligand is bound as the NH tautomer with a hydrogen bond between the NH group and the oxygen atom of the acetone of crystallization (N⋯O = 2.71 A). UO2(bmppt)2(dmso)· acetone crystallizes in the monoclinic space group P21/n with a = 16.010(2), b = 11.050(2), c = 23.084(4), β = 98.77(2)°, Z = 4, V = 4035.7, pcalc = 1.63 g cm−3, RF = 0.052, RwF = 0.090. The crystal structure shows discrete molecules of UO2(bmppt)2(dmso) with a pentagonal bipyramidal geometry. The UO22+ group is coordinated with two bidentate bmppt anions and the oxygen of a dmso molecule in the equatorial plane. The bmppt anions are bound quite unsymmetrically. The dihedral angle between the plane of one bmppt anion (US = 2.836(6), UO = 2.36(1) A) and the uranyl equatorial plane is 38.5° while for the other bmppt anion (US = 2.902(6), UO = 2.29(1) A) the dihedral angle is only 11°.
First-Passage and Extreme-Value Statistics of a Particle Subject to a Constant Force Plus a Random Force

We consider a particle which moves on the x axis and is subject to a constant force, such as gravity, plus a random force in the form of Gaussian white noise. We analyze the statistics of first arrival at point x1 of a particle which starts at x0 with velocity v0. The probability that the particle has not yet arrived at x1 after a time t, the mean time of first arrival, and the velocity distribution at first arrival are all considered. We also study the statistics of the first return of the particle to its starting point. Finally, we point out that the extreme-value statistics of the particle and the first-passage statistics are closely related, and we derive the distribution of the maximum displacement m=max t[x(t)].
Facile preparation of di- and monofluoromethyl ketones from trifluoromethyl ketones via fluorinated enol silyl ethers

Di- and monofluoromethyl ketones were prepared from the readily available trifluoromethyl ketones in high yields. Magnesium metal mediated reductive defluorination readily generates fluorinated enol silyl ethers, which upon fluoride or acid assisted hydrolysis give the respective ketones in good to excellent yields.
A radar simulation program for a 1024-processor hypercube

We have developed a fast parallel version of an existing synthetic aperture radar (SAR) simulation program, SRIM. On a 1024-processor NCUBE hypercube it runs an order of magnitude faster than on a CRAY X-MP or CRAY Y-MP processor. This speed advantage is coupled with an order of magnitude advantage in machine acquisition cost. SRIM is a somewhat large (30,000 lines of Fortran 77) program designed for uniprocessors; its restructuring for a hypercube provides new lessons in the task of altering older serial programs to run well on modern parallel architectures. We describe the techniques used for parallelization, and the performance obtained. Several novel parallel approaches to problems of task distribution, data distribution, and direct output were required. These techniques increase performance and appear to have general applicability for massive parallelism. We describe the hierarchy necessary to dynamically manage (i.e., load balance) a large ensemble. The ensemble is used in a heterogeneous manner, with different programs on different parts of the hypercube. The heterogeneous approach takes advantage of the independent instruction streams possible on MIMD machines.
Geometry of feasible injection region of power networks

We investigate the problem of power flow and its implications to the optimization in power networks. To understand how to solve these optimization problems, we look at the injection region of power networks. The injection region of a network is the set of all vectors of power injections, one at each bus, that can be achieved while satisfying the network and operation constraints. If there are no operation constraints, we show the injection region of a network is the set of all injections satisfying the conservation of energy. If the network has a tree topology, we show that the injection region with voltage magnitude, line loss constraints, line flow constraints and certain bus power constraints has the same set of Pareto optimal points as its convex hull. The set of Pareto-optimal points are of interest since these are the the optimal solutions to the minimization of a increasing convex function over the injection region. For non-tree networks, we obtain a weaker result by characterize the convex hull of the voltage constraint injection region for lossless cycles, a lossless cycle with a chord and certain combinations of these networks. The convex hull is of interest since they correspond to optimizing linear functions.
Engineering DNA-based functional materials

While DNA is a genetic material, it is also an inherently polymeric material made from repeating units called nucleotides. Although DNA's biological functions have been studied for decades, the polymeric features of DNA have not been extensively exploited until recently. In this tutorial review, we focus on two aspects of using DNA as a polymeric material: (1) the engineering methods, and (2) the potential real-world applications. More specifically, various strategies for constructing DNA-based building blocks and materials are introduced based on DNA topologies, which include linear, branched/dendritic, and networked. Different applications in nanotechnology, medicine, and biotechnology are further reviewed.
Iterated Brownian Motion in Parabola-Shaped Domains

Iterated Brownian motion Zt serves as a physical model for diffusions in a crack. If τD(Z) is the first exit time of this processes from a domain D⊂ℝn, started at z∈D, then Pz[τD(Z)>t] is the distribution of the lifetime of the process in D. In this paper we determine the large time asymptotics of \(P_{z}[\tau _{P_{\alpha}}(Z)>t]\) which gives exponential integrability of \(\tau _{P_{\alpha}}(Z)\) for parabola-shaped domains of the form Pα={(x,Y)∈ℝ×ℝn−1:x>0, |Y| 0. We also obtain similar results for twisted domains in ℝ2 as defined in DeBlassie and Smits: Brownian motion in twisted domains, Preprint, 2004. In particular, for a planar iterated Brownian motion in a parabola \(\mathcal{P}=\{(x,y):\ x>0,\ |y|<\sqrt{x}\}\) we find that for z∈℘ $$\lim_{t\to\infty}t^{-{1/7}}\log P_{z}[\tau _{\mathcal{P}}(Z)>t]=-\frac{7\pi ^{2}}{2^{25/7}}.$$