cssi/SciSciGPT-SciSciNet huggingface dataset:
PROSPECTIVE STUDY OF UNPLANNED ADMISSION TO THE INTENSIVE CARE UNIT AFTER TOTAL HIP ARTHROPLASTY

Purpose Triage to the intensive care unit (ICU) after elective total hip arthroplasty (THA) proves a complex medical and resource decision point. This study tested a model of pre-operative risk stratification at a tertiary, high-volume arthroplasty centre. Methods 175 consecutive THA patients were prospectively triaged to either an ICU bed or routine post-operative floor according to admission criteria based on a prior study of 1259 THA patients. The threshold for ICU admission was >=2 risk factors: age >75 years, revision surgery, creatinine clearance 35. Primary endpoints were a reduction in unplanned admission to the ICU, as well as major complications. A pre-study power analysis demonstrated adequate patient numbers. Results All patients were prospectively triaged and followed during the study period. After implementation of our triage model, the rate of unplanned ICU admissions dropped from 7.1 % to 2.2% (p=0.013). The as-treated odds of unplanned admission pre-versus post-intervention were 3.2 (1.2, 10.6). In an intent-to-treat analysis, the unplanned admission rate was 0.6% (p Conclusions Pre-operative triage to the ICU according to selected risk factors affects a reduction in post-operative unplanned ICU admissions and major complications after elective total joint arthroplasty.
An Acoustic Transponder System

Acoustic transponders provide a particularly appropriate means for navigating relative to the deep sea floor. Their successful use, however, is dependent on solution of certain engineering problems and on understanding of the sound propagation situation in which the equipment is to be used. During the past year we have developed, built and used a set of appropriate, inexpensive transponders. These allow for selective calling of any one of three units (using pulses at 10.0, 10.5 or 11.0 kc) all of which reply at 12.0 kc. The design lifetime is 106 pulses delivered over a period of up to one year. They have been built primarily to provide tracking information for a deeply towed, unmanned vehicle used for echo sounding and magnetometer observations. With this system useful responses have been obtained to ranges of 8 nautical miles. In normal operation the useful range is limited by the shadow zone formed by upward refraction of the acoustic energy near the sea floor. Use at sea has shown that these elements can provide effective navigational information and has allowed direct observation of the shadowing effects as the principal range limiting factor.
Keynes’s Identity, Ricardian Virtue and the Partial Dichotomy

What was the contribution of Lord Keynes to the development of general equilibrium theory? It is becoming possible now, with the passage of a quarter-century, to view Keynes’s General Theory as an (important) episode in the continuous development of general neo-classical systems. From one vantage point, it is paradoxical that his work should have been accepted as the Grand Departure from its neo-classical progenitors — even though Keynes presented it in that light — since his interpretations of these systems are almost always kept visible for purposes of comparison. On the other hand, Keynes’s impact on economic policy, on the methodology and analytics of quantitative economics, and on the working economist’s ‘vision’ of reality, may be seen even today to be of that order of power rightfully termed ‘revolutionary’.
Sampling Issues in Estimating Radar Variables from Disdrometer Data

AbstractSimulation of sampling from gamma-distributed raindrop populations demonstrates that significant biases and substantial errors can occur in estimates of polarimetric radar variables based on samples of raindrop populations obtained with disdrometers. Biases and RMS errors of 0.5 dB or more in estimates of differential reflectivity Zdr can occur with samples of even a few hundred drops; significant biases and errors also occur in estimates of reflectivity ZH or specific differential phase Kdp. The results indicate that very large samples would be required to obtain adequate representation of the population characteristics for many radar applications. They also suggest that greater attention is needed to the sample sizes in the disdrometer data used in developing polarimetric rainfall-rate estimators or hydrometeor classification algorithms.
Spectral Irradiance Calibration in the Infrared. XI. Comparison of α Bootis and 1 Ceres with a Laboratory Standard

Infrared spectra of two celestial objects frequently used as flux standards are calibrated against an absolute laboratory flux standard at a spectral resolving power of 100 to 200. The spectrum of the K1.5III star, alpha Boo, is measured from 3 microns to 30 microns and that of the C-type asteroid, 1 Ceres, from 5 microns to 30 microns. While these 'standard' spectra do not have the apparent precision of those based on calculated models, they do not require the assumptions involved in theoretical models of stars and asteroids. Specifically they provide a model-independent means of calibrating celestial flux in the spectral range from 12 microns to 30 microns where accurate absolute photometry is not available. The agreement found between the spectral shapes of alpha Boo and Ceres based on laboratory standards, and those based on observed ratios to alpha CMa (Sirius) and alpha Lyr (Vega), flux calibrated by theoretical modeling of these hot stars strengthens our confidence in the applicability of the stellar models as primary irradiance standards.
Nutrient enrichment induces dormancy and decreases diversity of active bacteria in salt marsh sediments.

Microorganisms control key biogeochemical pathways, thus changes in microbial diversity, community structure and activity can affect ecosystem response to environmental drivers. Understanding factors that control the proportion of active microbes in the environment and how they vary when perturbed is critical to anticipating ecosystem response to global change. Increasing supplies of anthropogenic nitrogen to ecosystems globally makes it imperative that we understand how nutrient supply alters active microbial communities. Here we show that nitrogen additions to salt marshes cause a shift in the active microbial community despite no change in the total community. The active community shift causes the proportion of dormant microbial taxa to double, from 45 to 90%, and induces diversity loss in the active portion of the community. Our results suggest that perturbations to salt marshes can drastically alter active microbial communities, however these communities may remain resilient by protecting total diversity through increased dormancy. Increased anthropogenic nitrogen inputs into the biosphere are fundamentally altering ecosystems worldwide. Here, Kearns et al.show that a decade of nitrogen additions to salt marshes reduces the proportion of active microorganisms, despite no net change to the total microbial community.
Constant approximation algorithm for non-uniform capacitated multi-item lot-sizing via strong covering inequalities

We study the non-uniform capacitated multi-item lot-sizing (CMILS) problem. In this problem, there is a set of demands over a planning horizon of T time periods and all demands must be satisfied on time. We can place an order at the beginning of each period s, incurring an ordering cost Ks. The total quantity of all products ordered at time s can not exceed a given capacity Cs. On the other hand, carrying inventory from time to time incurs inventory holding cost. The goal of the problem is to find a feasible solution that minimizes the sum of ordering and holding costs.Levi et al. (Levi, Lodi and Sviridenko, Mathmatics of Operations Research 33(2), 2008) gave a 2-approximation for the problem when the capacities Cs are the same. In this paper, we extend their result to the case of non-uniform capacities. That is, we give a constant approximation algorithm for the capacitated multi-item lot-sizing problem with general capacities.The constant approximation is achieved by adding an exponentially large set of new covering inequalities to the natural facility-location type linear programming relaxation for the problem. Along the way of our algorithm, we reduce the CMILS problem to two generalizations of the classic knapsack covering problem. We give LP-based constant approximation algorithms for both generalizations, via the iterative rounding technique.
Subdivision and Spline Spaces

A standard construction in approximation theory is mesh refinement. For a simplicial or polyhedral mesh $$\varDelta \subseteq {\mathbb R}^k$$ , we study the subdivision $$\varDelta '$$ obtained by subdividing a maximal cell of $$\varDelta $$ . We give sufficient conditions for the module of splines on $$\varDelta '$$ to split as the direct sum of splines on $$\varDelta $$ and splines on the subdivided cell. As a consequence, we obtain dimension formulas and explicit bases for several commonly used subdivisions and their multivariate generalizations.
A comparison of race‐related pain stereotypes held by White and Black individuals

Pain judgments are the basis for pain management. The purpose of this study was to assess Black and White participants' race-related pain stereotypes. Undergraduates (n=551) rated the pain sensitivity and willingness to report pain for the typical Black person, White person, and themselves. Participants, regardless of race, rated the typical White person as being more pain sensitive and more willing to report pain than the typical Black person. White participants rated themselves as less sensitive and less willing to report pain than same-race peers; however, Black participants rated themselves as more pain sensitive and more willing to report pain than same-race peers. These findings highlight similarities and differences in racial stereotypic pain beliefs held by Black and White individuals.
Drift Barriers to Quality Control When Genes Are Expressed at Different Levels.

Gene expression is imperfect, sometimes leading to toxic products. Solutions take two forms: globally reducing error rates, or ensuring that the consequences of erroneous expression are relatively harmless. The latter is optimal, but because it must evolve independently at so many loci, it is subject to a stringent "drift barrier"-a limit to how weak the effects of a deleterious mutation s can be, while still being effectively purged by selection, expressed in terms of the population size N of an idealized population such that purging requires s < -1/N In previous work, only large populations evolved the optimal local solution, small populations instead evolved globally low error rates, and intermediate populations were bistable, with either solution possible. Here, we take into consideration the fact that the effectiveness of purging varies among loci, because of variation in gene expression level, and variation in the intrinsic vulnerabilities of different gene products to error. The previously found dichotomy between the two kinds of solution breaks down, replaced by a gradual transition as a function of population size. In the extreme case of a small enough population, selection fails to maintain even the global solution against deleterious mutations, explaining the nonmonotonic relationship between effective population size and transcriptional error rate that was recently observed in experiments on Escherichia coli, Caenorhabditis elegans, and Buchnera aphidicola.
GPR4 deficiency alleviates intestinal inflammation in a mouse model of acute experimental colitis.

GPR4 is a proton-sensing G protein-coupled receptor that can be activated by extracellular acidosis. It has recently been demonstrated that activation of GPR4 by acidosis increases the expression of numerous inflammatory and stress response genes in vascular endothelial cells (ECs) and also augments EC-leukocyte adhesion. Inhibition of GPR4 by siRNA or small molecule inhibitors reduces endothelial cell inflammation. As acidotic tissue microenvironments exist in many types of inflammatory disorders, including inflammatory bowel disease (IBD), we examined the role of GPR4 in intestinal inflammation using a dextran sulfate sodium (DSS)-induced acute colitis mouse model. We observed that GPR4 mRNA expression was increased in mouse and human IBD tissues when compared to control intestinal tissues. To determine the function of GPR4 in intestinal inflammation, wild-type and GPR4-deficient mice were treated with 3% DSS for 7 days to induce acute colitis. Our results showed that the severity of colitis was decreased in GPR4-deficient DSS-treated mice in comparison to wild-type DSS-treated mice. Clinical parameters, macroscopic disease indicators, and histopathological features were less severe in the DSS-treated GPR4-deficient mice than the DSS-treated wild-type mice. Endothelial adhesion molecule expression, leukocyte infiltration, and isolated lymphoid follicle (ILF) formation were reduced in intestinal tissues of DSS-treated GPR4-null mice. Collectively, our results suggest GPR4 provides a pro-inflammatory role in the inflamed gut as the absence of GPR4 ameliorates intestinal inflammation in the acute experimental colitis mouse model.
Physics and experiments at RHIC

The Relativistic Heavy Ion Collider (RHIC), under construction at Brookhaven National Laboratory, will be the site of a series of experiments seeking to discover the quark-gluon plasma and elucidate its properties. Several observables should exhibit characteristic behaviors if a quark-gluon plasma is indeed created in the laboratory. Four experiments are now under construction for RHIC to measure certain of these observables over kinematic ranges where effects due to quark-gluon plasma formation should be manifest.
Numerical Modeling and Simulation of Combustion Phenomena Related to Thermal Ignition and Flame Fronts

In this study, we consider problems of thermal ignition and flame front propagation. Ordinary and partial differential equations with proper initial and boundary conditions are solved for generic cases. Numerical schemes are tested and results are discussed. Comparisons with the literature for benchmark cases are favorable.
Dichroism optical-resolution photoacoustic microscopy

We have developed dichroism optical-resolution photoacoustic microscopy, capable of imaging polarization-dependent optical absorption (i.e., dichroism) with excellent specificity. This technical innovation enriches molecular photoacoustic contrasts and holds particular potential for detecting amyloid-associated neurodegenerative and cardiovascular diseases.
Glyph: Visualization Tool for Understanding Problem Solving Strategies in Puzzle Games.

Understanding player strategies is a key question when analyzing player behavior both for academic researchers and industry practitioners. For game designers and game user researchers, it is important to gauge the distance between intended strategies and emergent strategies; this comparison allows identification of glitches or undesirable behaviors. For academic researchers using games for serious purposes such as education, the strategies adopted by players are indicative of their cognitive progress in relation to serious goals, such as learning process. Current techniques and systems created to address these needs present a few drawbacks. Qualitative methods are difficult to scale upwards to include large number of players and are prone to subjective biases. Other approaches such as visualization and analytical tools are either designed to provide an aggregated overview of the data, losing the nuances of individual player behaviors, or, in the attempt of accounting for individual behavior, are not specifically designed to reduce the visual cognitive load. In this work, we propose a novel visualization technique that specifically addresses the tasks of comparing behavior sequences in order to capture an overview of the strategies enacted by players and at the same time examine individual player behaviors to identify differences and outliers. This approach allows users to form hypotheses about player strategies and verify them. We demonstrate the effectiveness of the technique through a case study: utilizing a prototype system to investigate data collected from a commercial educational puzzle game. While the prototype’s usability can be improved, initial testing results show that core features of the system proved useful to our potential users for understanding player strategies.
INTRA-OPERATIVE MCL INJURY REQUIRES CONSTRAINED COMPONENTS – AFFIRMS

The use of constrained condylar components (CCK) in primary total knee arthroplasty is infrequent and unusual. The usual indications are a severe fixed valgus deformity with a stretched or incompetent medial collateral ligament (MCL). This may occur in an elderly female patient with valgus osteoarthritis, advanced rheumatoid arthritis, or other less common disorders: polio, Parkinson9s disease, and Paget9s disease involving the knee. It may also be seen in younger patients with post-traumatic arthritis. Beware of the patient with a prior history of a knee injury in which staples were placed at the medial epicondyle of the femur or proximal tibia, indicating likely MCL injury, or a knee with extensive medial joint heterotopic ossification. An unusual indication for a primary CCK component is inadvertent injury or sectioning of the MCL during the procedure. This can occur with over-zealous medial ligament release or division with the saw during the posterior femoral condylar or proximal tibial resection. This has been reported to occur in
Coherent Programming in the Lincoln Reckoner

"Coherent programming" refers to a set of conventions and techniques that we believe have the power to shape the growth of a library of programs, so that a user may draw upon them freely and with minimal concern about the details of their compatibility. The purpose of this paper is to explain the concept of coherence, and to show how it has been applied in the Lincoln Reckoner, an on-line system that provides computational assistance to scientists and engineers. The external specifications of the Reckoner, which have been presented elsewhere [1], will not be discussed here. Rather, this paper will concentrate on some of the " architectural" considerations in the design of user-oriented on-line systems.
Novel use of photovoltaics for backup spacecraft laser communication system

Communication with a spacecraft is typically performed using Radio Frequency (RF). RF is a well-established and well-regulated technology that enables communication over long distances as proven by the Voyager 1 & II missions. However, RF requires licensing of very limited radio spectrum and this poses a challenge in the future, particularly with spectrum time-sharing. This is of a concern for emergency communication when it is of utmost urgency to contact the spacecraft and maintain contact, particularly when there is a major mission anomaly or loss of contact. For these applications, we propose a backup laser communication system where a laser is beamed towards a satellite and the onboard photovoltaics acts as a laser receiver. This approach enables a laser ground station to broadcast commands to the spacecraft in times of emergency. Adding an actuated reflector to the laser receiver on the spacecraft enables two-way communication between ground and the spacecraft, but without the laser being located on the spacecraft. In this paper, we analyze the feasibility of the concept in the laboratory and develop a benchtop experiment to verify the concept. We have also developed a preliminary design for a 6U CubeSat-based demonstrator to evaluate technology merits.
Global solutions for the gravity water waves equation in dimension 3

We show existence of global solutions for the gravity water waves equation in dimension 3, in the case of small data. The proof combines energy estimates, which yield control of L 2 related norms, with dispersive estimates, which give decay in L 8 . To obtain these dispersive estimates, we use an analysis in Fourier space; the study of space and time resonances is then the crucial point.
Non-relativistic geometry of holographic screens

We propose that the intrinsic geometry of holographic screens should be described by the Newton-Cartan geometry. As a test of this proposal, we show that the evolution equations of the screen can be written in a covariant form in terms of a stress tensor, an energy current, and a momentum one-form. We derive the expressions for the stress tensor, energy density, and momentum one-form using Brown-York action formalism.
Effects of a Year Long Supplemental Reading Intervention for Students with Reading Difficulties in Fourth Grade.

Research examining effective reading interventions for students with reading difficulties in the upper elementary grades is limited relative to the information available for the early elementary grades. In the current study, we examined the effects of a multicomponent reading intervention for students with reading comprehension difficulties. We used a partially nested analysis with latent variables to adequately match the design of the study and provide the necessary precision of intervention effects. We examined the effects of the intervention on students’ latent word reading, latent vocabulary, and latent reading comprehension. In addition, we examined whether these effects differed for students of varying levels of reading or English language proficiency. Findings indicated the treatment significantly outperformed the comparison on reading comprehension (Effect Size = 0.38), but no overall group differences were noted on word reading or vocabulary. Students’ initial word reading scores moderated this effect. Reading comprehension effects were similar for English learner and non-English learner students. (PsycINFO Database Record (c) 2017 APA, all rights reserved)
Gender Equality in Mortgage Lending

Using a sample of 30-year fixed-rate subprime mortgage loans, this article empirically examines whether gender inequality exists in the mortgage market, specifically whether a borrower's gender affects the loan contract rate charged, beyond the impact of the borrower's probability of default and prepayment. The results, based on a competing-risks loan hazard model, reveal that borrowers of different genders have different loan termination patterns. After controlling for the probability of a borrower defaulting or prepaying, female borrowers pay higher contract rates in the subprime mortgage market over the study period.
A photoconversion model for full spectral programming and multiplexing of optogenetic systems

Abstract Optogenetics combines externally applied light signals and genetically engineered photoreceptors to control cellular processes with unmatched precision. Here, we develop a mathematical model of wavelength‐ and intensity‐dependent photoconversion, signaling, and output gene expression for our two previously engineered light‐sensing Escherichia coli two‐component systems. To parameterize the model, we develop a simple set of spectral and dynamical calibration experiments using our recent open‐source “Light Plate Apparatus” device. In principle, the parameterized model should predict the gene expression response to any time‐varying signal from any mixture of light sources with known spectra. We validate this capability experimentally using a suite of challenging light sources and signals very different from those used during the parameterization process. Furthermore, we use the model to compensate for significant spectral cross‐reactivity inherent to the two sensors in order to develop a new method for programming two simultaneous and independent gene expression signals within the same cell. Our optogenetic multiplexing method will enable powerful new interrogations of how metabolic, signaling, and decision‐making pathways integrate multiple input signals.
New degree bounds for polynomial threshold functions

A real multivariate polynomial p(x 1, …, x n ) is said to sign-represent a Boolean function f: {0,1}n →{−1,1} if the sign of p(x) equals f(x) for all inputs x∈{0,1}n . We give new upper and lower bounds on the degree of polynomials which sign-represent Boolean functions. Our upper bounds for Boolean formulas yield the first known subexponential time learning algorithms for formulas of superconstant depth. Our lower bounds for constant-depth circuits and intersections of halfspaces are the first new degree lower bounds since 1968, improving results of Minsky and Papert. The lower bounds are proved constructively; we give explicit dual solutions to the necessary linear programs.
DNA sequence homology induces cytosine-to-thymine mutation by a heterochromatin-related pathway in Neurospora

Most eukaryotic genomes contain substantial amounts of repetitive DNA organized in the form of constitutive heterochromatin and associated with repressive epigenetic modifications, such as H3K9me3 and C5 cytosine methylation (5mC). In the fungus Neurospora crassa, H3K9me3 and 5mC are catalyzed, respectively, by a conserved SUV39 histone methyltransferase, DIM-5, and a DNMT1-like cytosine methyltransferase, DIM-2. Here we show that DIM-2 can also mediate repeat-induced point mutation (RIP) of repetitive DNA in N. crassa. We further show that DIM-2-dependent RIP requires DIM-5, HP1, and other known heterochromatin factors, implying a role for a repeat-induced heterochromatin-related process. Our previous findings suggest that the mechanism of repeat recognition for RIP involves direct interactions between homologous double-stranded DNA (dsDNA) segments. We thus now propose that, in somatic cells, homologous dsDNA-dsDNA interactions between a small number of repeat copies can nucleate a transient heterochromatic state, which, on longer repeat arrays, may lead to the formation of constitutive heterochromatin.
Improved Private Set Intersection Against Malicious Adversaries

Private set intersection (PSI) refers to a special case of secure two-party computation in which the parties each have a set of items and compute the intersection of these sets without revealing any additional information. In this paper we present improvements to practical PSI providing security in the presence of malicious adversaries.
On Removing Graded Encodings from Functional Encryption

Functional encryption (FE) has emerged as an outstanding concept. By now, we know that beyond the immediate application to computation over encrypted data, variants with succinct ciphertexts are so powerful that they yield the full might of indistinguishability obfuscation (IO). Understanding how, and under which assumptions, such succinct schemes can be constructed has become a grand challenge of current research in cryptography. Whereas the first schemes were based themselves on IO, recent progress has produced constructions based on constant-degree graded encodings. Still, our comprehension of such graded encodings remains limited, as the instantiations given so far have exhibited different vulnerabilities.
Partial hydrodynamic representation of quantum molecular dynamics

A hybrid method is proposed to propagate system-bath quantum dynamics that use both basis functions and coupled quantum trajectories. In it, the bath is represented with an ensemble of Bohmian trajectories while the system degrees of freedom are accounted through reduced density matrices. By retaining the Hilbert space structure for the system, the method is able to capture interference processes that are challenging to describe in Bohmian dynamics due to singularities that these processes introduce in the quantum potential. By adopting quantum trajectories to represent the bath, the method beats the exponential scaling of the computational cost with the bath size. This combination makes the method suitable for large-scale ground and excited state fully quantum molecular dynamics simulations. Equations of motion for the quantum trajectories and reduced density matrices are derived from the Schrodinger equation and a computational algorithm to solve these equations is proposed. Through computations in two-dimensional model systems, the method is shown to offer an accurate description of subsystem observables and of quantum decoherence, which is difficult to obtain when the quantum nature of the bath is ignored. The scaling of the method is demonstrated using a model with 21 degrees of freedom. The limit of independent trajectories is recovered when the mass of bath degrees of freedom is much larger than the one of the system, in agreement with mixed quantum-classical descriptions.
Learn Physics by Programming in Haskell

We describe a method for deepening a student’s understanding of basic physics by asking the student to express physical ideas in a functional programming language. The method is implemented in a second-year course in computational physics at Lebanon Valley College. We argue that the structure of Newtonian mechanics is clarified by its expression in a language (Haskell) that supports higherorder functions, types, and type classes. In electromagnetic theory, the type signatures of functions that calculate electric and magnetic fields clearly express the functional dependency on the charge and current distributions that produce the fields. Many of the ideas in basic physics are well-captured by a type or a function.
Are global trade negotiations behind a fragmented world of "gated globalization"?

Abstract We show that global trade negotiations can prevent global free trade. In a simple model where global tariff negotiations precede sequential Free Trade Agreements (FTAs), we show FTA formation can expand all the way to global free trade in the absence of global tariff negotiations but global free trade never emerges when global tariff negotiations precede FTA formation. This result arises precisely because global tariff negotiations successfully elicit concessions from negotiating countries. Moreover, global tariff negotiations can produce a fragmented world of “gated globalization” where some countries form FTAs that eliminate tariff barriers among themselves while outsiders continue facing higher tariffs.
Systems Combining Linearity and Saturations, and Relations of “Neural Nets”

Abstract This paper deals with control systems consisting of linearly interconnected integrators (or delay lines) and scalar nonlinearities. For linear systems with saturating sensors, we mention results on observability and minimal realization. When saturations appear in actuators, questions of control become of interest, and we describe stabilization techniques. If there are feedback loops containing the nonlinearities, “recurrent neural nets” are obtained, and we discuss various issues relating to their computational power and identifiability of parameters. Parts of the work surveyed here were jointly pursued with Francesca Albertini, Renee Schwarzschild, Hava Siegelmann, Hector Sussmann, and Yudi Yang.
Generalized delta functions and their use in quantum optics

The Dirac delta function δ(x) is widely used in many areas of physics and mathematics. Here we consider the generalization of a Dirac delta function to allow the use of complex arguments. We show that the properties of a generalized delta function are very different from those of a Dirac delta function and that they behave more like a pole in the complex plane. We use the generalized delta function to derive the Glauber-Sudarshan P-function, P(α), for a Schrodinger cat state in a surprisingly simple form. Aside from their potential applications in classical electromagnetism and quantum optics, these results provide insight into the ability of the diagonal P-function to describe density operators with off-diagonal elements.
Cone-Bounded Nonlinearities and Mean-Square Bounds --Smoothing and Prediction

Abstract Mean-square performance bounds are derived for smoothing and prediction problems associated with a class of nonlinear dynamic systems. The systems considered are partially-observed finite-dimensional continuous-time stochastic processes driven by additive white Gaussian noise. The particular systems to which the bounds apply are those which, when modeled by Ito differential equations, contain drift (.dt) coefficients which are, to within a uniformly Lipschitz residual, jointly linear in the system state and externally applied control. The bounds derived in this paper include lower bounds on the error covariance attainable by any smoother or any predictor, including the optimum, and upper bounds on the performance of some simple, almost-linear predictors reminiscent of the designs which are optimal in the linear case. All bounds hold for correlated system and observation noises. The lower bounds on smoothing and prediction performance are established using measure-transformation techniques to relate a version of the nonlinear problem to its linearization. The upper bound on prediction performance is obtained by exploiting the cone-bounded nature of the nonlinearities to construct second-moment analysis of the mean-square error that is closed in the sense that it evolves without reference to higher order moments. All the bounds are rigorously derived and independent of control or control law. In each case, the computational effort is comparable to that for the corresponding optimum linear smoothing, prediction or filtering problem. They converge with vanishing nonlinearity (vanishing Lipschitz constants) to the known optimum performance for the limiting linear system. Consequently, the bounds are asymptotically tight and the simple designs studied are asymptotically optimal with vanishing nonlinearity.
The Acquired Immunodeficiency Syndrome in Gay Men

Abstract The acquired immunodeficiency syndrome (AIDS) is a major health problem for gay men in the United States. About three fourths of all reported cases have occurred in this population, and th...
Stationary Distribution of a Generalized LRU-MRU Content Cache

Many different caching mechanisms have been previously proposed, exploring different insertion and eviction policies and their performance individually and as part of caching networks. We obtain a novel closed-form stationary invariant distribution for a generalization of Least Recently Used (LRU) and Most Recently Used (MRU) eviction for single caching nodes under a reference Markov model. Numerical comparisons are made with an “Incremental Rank Progress” (IRP a.k.a. CLIMB) and random eviction (RE a.k.a. random replacement, RANDOM) methods under a steady-state Zipf popularity distribution. The range of cache hit probabilities is smaller under MRU and larger under IRP compared to LRU. We conclude with the invariant distribution for a special case of a RE caching tree-network.
Rapid Adrenocorticotropic Hormone Test in Practice. Retrospective Review

Retrospective analysis of the rapid adrenocorticotropic hormone (ACTH) test in a large adult population shows a marked interdependence of the basal cortisol concentration, peak cortisol concentration, and increase in cortisol concentration. Repetition of the rapid ACTH test in the same patient does not improve diagnostic accuracy. A significant number of falsely abnormal rapid ACTH test results were observed (in comparison to continuous ACTH infusion as a reference test). This supports the use of the rapid ACTH test as a screening test, but not as a diagnostic test for adrenocortical failure. It is proposed that a peak cortisol level greater than or equal to 20 micrograms/dl (550 nmol/liter) is a sufficient single criterion for normal adrenal function as assessed by the rapid ACTH test.
Acute Primary Hyperparathyroidism

Acute primary hyperparathyroidism is an unusual form of primary hyperparathyroidism characterized by life-threatening hypercalcemia. Forty-three cases reported in the literature since 1974 are reviewed, along with five new cases. The average age of the patients was 55 (27 to 82), with an even distribution between men and women. Marked hypercalcemia (17.5 +/- 2.1 mg/dl) was accompanied by parathyroid hormone levels 20 times normal. Virtually all patients had symptoms. Hyperparathyroid bone disease occurred in 53 percent of patients; even more (69 percent) had nephrolithiasis or nephrocalcinosis. Combined renal and skeletal involvement was seen in 50 percent. Only three deaths were recorded. The pathophysiology of the acute hyperparathyroid state is unknown but appears to consist of uncontrolled parathyroid hormone secretion followed by cycles of hypercalcemia, polyuria, dehydration, reduced renal function, and worsening hypercalcemia. These features of acute primary hyperparathyroidism are compared with the features reported in the literature antedating multichannel screening, and with the features of the common form of primary hyperparathyroidism. Clinical guidelines by which the diagnosis may be suspected are also reviewed.
Epsilon-Trig Regularization Method for Bang-Bang Optimal Control Problems

Bang-bang control problems have numerical issues due to discontinuities in the control structure and require smoothing when using optimal control theory that relies on derivatives. Traditional smooth regularization introduces a small error into the original problem using error controls and an error parameter to enable the construction of accurate smoothed solutions. When path constraints are introduced into the problem, the traditional smooth regularization fails to bound the error controls involved. It also introduces a dimensional inconsistency related to the error parameter. Moreover, the traditional approach solves for the error controls separately, which makes the problem formulation complicated for a large number of error controls. The proposed Epsilon-Trig regularization method was developed to address these issues by using trigonometric functions to impose implicit bounds on the controls. The system of state equations is modified such that the smoothed control is expressed in sine form, and only one of the state equations contains an error control in cosine form. Since the Epsilon-Trig method has an error parameter only in one state equation, there is no dimensional inconsistency. Moreover, the Epsilon-Trig method only requires the solution to one control, which greatly simplifies the problem formulation. Its simplicity and improved capability over the traditional smooth regularization method for a wide variety of problems including the Goddard rocket problem have been discussed in this study.
Services Trade and Global Value Chains

Services play a role in global value chains in many ways, similar to goods. But services deserve special attention because of how they are transacted, how they affect downstream sectors, how they are regulated, and how international cooperation can contribute to integrating national markets. Databases on trade in value added, which cover only cross-border transactions in services, reveal a high and growing share of services in trade in value added across countries and industries. Although international transactions in services that take place through foreign investment are difficult to measure, their economic impact can be estimated. The resulting improved access to financial, communications, and transport services facilitates the emergence of global value chains, enhances downstream manufacturing firms’ productivity, and shifts the pattern of comparative advantage toward sectors intensive in these services. Despite significant unilateral liberalization, service markets in many countries remain protected by restrictions on the entry of foreign services and service providers, as well as discretionary and discriminatory regulatory requirements. International cooperation in services has attempted to follow the example of reciprocal market opening for goods, but this approach has delivered little incremental liberalization. More could be achieved through greater emphasis on international regulatory cooperation.
Terminator field-aligned current system: Its dependencies on solar, seasonal, and geomagnetic conditions

Abstract A new field-aligned current system in the high-latitude ionosphere, the terminator field-aligned currents, was recently discovered by Zhu et al. (2014). A series of modeling, observational, and theoretical studies need to be performed in order to get a full picture of the behavior and properties of this newly discovered current system, understand the underlying physics, and explore its effects on the electrodynamics and plasma dynamics of the high-latitude ionosphere. As a first step in this direction, we performed a systematic study on the seasonal, solar, and geomagnetic dependencies of the general properties of the terminator field-aligned currents. The study was conducted by using a physics-based data assimilation model, Ionospheric Dynamics and Electrodynamics Data Assimilation (IDED-DA) Model, with the ingestion of observational data.
Stresses at a Re-Entrant Corner of a Plate

Floors of modern buildings unsupported by intermediate columns present re-entrant corners; stresses at corners are theoretically infinite, but become finite in immediate neighborhood of corner; thus practical design stresses can be obtained by substituting for actual plate, circular sector simply supported in its circular boundary and built in on its straight sides; such stresses are derived for case of circular sector with right angle cutout.
Learning algorithms for active learning

We introduce a model that learns active learning algorithms via metalearning. For a distribution of related tasks, our model jointly learns: a data representation, an item selection heuristic, and a prediction function. Our model uses the item selection heuristic to construct a labeled support set for training the prediction function. Using the Omniglot and MovieLens datasets, we test our model in synthetic and practical settings.
Possibilities of Improved Therapy for Cancer Patients

It is indeed an honor to have been invited by Dr. Cowdry and the Board of the Barnard Free Skin and Cancer Hospital to give the second Barnard Hospital Lecture, particularly because St. Louis is one of the oldest and most important centers of experimental and clinical cancer research in the country. Since I am a laboratory worker, it was with some misgiving that I agreed to speak to you on the possibilities of improved therapy for cancer patients. However, I shall deal mainly with fundamental principles of therapy, and these are essentially the same, whether they arise in the clinic or in the experimental laboratory. It is my aim to discuss, briefly and as objectively as possible, various points which to my mind may lead to improvements in cancer therapy. These may be grouped into two broad classes: first, the more widespread application of known methods and their improvements;
Border correlations, lattices, and the subgraph component polynomial

Abstract We consider the border sets of partial words and study the combinatorics of specific representations of them, called border correlations, which are binary vectors of same length indicating the borders. We characterize precisely which of these vectors are valid border correlations, and establish a one-to-one correspondence between the set of valid border correlations and the set of valid ternary period correlations of a given length, the latter being ternary vectors representing the strong and strictly weak period sets. It turns out that the sets of all border correlations of a given length form distributive lattices under suitably defined partial orderings. We also give connections between the ternary period correlation of a partial word and its refined border correlation which specifies the lengths of all the word’s bordered cyclic shifts’ minimal borders. Finally, we investigate the population size, that is, the number of partial words sharing a given (refined) border correlation, and obtain formulas to compute it. We do so using the subgraph component polynomial of an undirected graph, introduced recently by Tittmann et al. (2011), which counts the number of connected components in vertex induced subgraphs.
Art and gender: market bias or selection bias?

We test for gender effects in the art market using auction prices for artists who graduated from the Yale School of Art. Yale’s female graduates have significantly fewer auction sales, controlling for their graduating year gender ratio. Conditioning upon sale, works by female artists obtained higher average prices. The results suggest that while institutions and career paths may condition on gender, the market may not.
Taking notes in the digital age: Evidence from classroom random control trials

Taking good notes is linked to success in college. However, increased use of computers to take notes necessitates reconsideration of the linkages between note-taking and learning. One difficulty is...
Direct solution of FEM models: Are sparse direct solvers the best strategy?

A brief summary of direct solution approaches for finite element methods (FEM) in computational electromagnetics (CEM) is given along with an alternative direct solution based on domain decomposition (DD). Unlike recent trends in approximate/low-rank solvers, this work focuses on ‘numerically exact’ solution methods as they are more reliable for complex ‘real-life’ models. Preliminary studies on general three dimensional geometries with unstructured FEM meshes suggest that the proposed direct DD methodology offers significant memory advantages over highly optimized, high-performance sparse direct solver libraries, while maintaining approximately comparable or slightly slower serial serial execution speed but with significantly better parallel and GPU processing prospects.
Magnetic field in expanding quark-gluon plasma

Intense electromagnetic fields are created in the quark-gluon plasma by the external ultrarelativistic valence charges. The time evolution and the strength of this field are strongly affected by the electrical conductivity of the plasma. Yet, it has recently been observed that the effect of the magnetic field on the plasma flow is small. We compute the effect of plasma flow on magnetic field and demonstrate that it is less than 10%. These observations indicate that the plasma hydrodynamics and the dynamics of electromagnetic field decouple. Thus, it is a very good approximation, on the one hand, to study QGP in the background electromagnetic field generated by external sources and, on the other hand, to investigate the dynamics of magnetic field in the background plasma. We also argue that the wake induced by the magnetic field in plasma is negligible.
Complementary metrics of human auditory nerve function derived from compound action potentials.

Loss or inactivity of auditory nerve (AN) fibers is thought to contribute to suprathreshold auditory processing deficits, but evidence-based methods to assess these effects are not available. We de...
Optimization of Drug Prescription and Medication Management in Older Adults with Cardiovascular Disease

Cardiovascular disease increases incrementally with age and elderly patients concomitantly sustain multimorbidities, with resultant prescription of multiple medications. Despite conforming with disease-specific cardiovascular clinical practice guidelines, this polypharmacy predisposes many elderly individuals with cardiovascular disease to adverse drug events and non-adherence. Patient-centered care requires that the clinician explore with each patient his or her goals of care and that this shared decision-making constitutes the basis for optimization of medication management. This approach to aligning therapies with patient preferences is likely to promote patient satisfaction, to limit morbidity, and to favorably affect healthcare costs.
Government guaranteed small business loans and regional growth

Abstract This paper examines the impact of government guaranteed small business loans on regional growth. I construct a metro-level panel of the Small Business Administration's guaranteed loans and examine economic growth between 1993 and 2002, across 316 metro areas in the US. A simple OLS regression finds a significant positive relationship between small business loans and regional growth. However, first-difference and instrumental variable regressions that mitigate endogeneity find no significant employment or income growth effects from small business loans. At least from an efficiency perspective, there seems to be no net gains to the regional economy from guaranteed small business loans.