cssi/SciSciGPT-SciSciNet huggingface dataset:
Dynamical eigenfunction decomposition of turbulent pipe flow

The results of an analysis of turbulent pipe flow based on a Karhunen–Loeve decomposition are presented. The turbulent flow is generated by a direct numerical simulation of the Navier–Stokes equations using a spectral element algorithm at a Reynolds number Reτ = 150. This simulation yields a set of basis functions that captures 90% of the energy after 2763 modes. The eigenfunctions are categorized into two classes and six subclasses based on their wavenumber and coherent vorticity structure. Of the total energy, 81% is in the propagating class, characterized by constant phase speeds; the remaining energy is found in the non-propagating subclasses, the shear and roll modes. The four subclasses of the propagating modes are the wall, lift, asymmetric and ring modes. The wall modes display coherent vorticity structures near the wall, the lift modes display coherent vorticity structures that lift away from the wall, the asymmetric modes break the symmetry about the axis, and the ring modes display rings of coh...
Stability of periodic orbits in no-slip billiards

Rigid bodies collision maps in dimension-two, under a natural set of physical requirements, can be classified into two types: the standard specular reflection map and a second which we call, after Broomhead and Gutkin, no-slip. This leads to the study of no-slip billiards—planar billiard systems in which the moving particle is a disc (with rotationally symmetric mass distribution) whose translational and rotational velocities can both change after collisions with the boundary of the billiard domain. This paper, which continues the investigation initiated in Cox and Feres (2017 Dynamical Systems, Ergodic Theory, and Probability: in Memory of Chernov (Providence, RI: American Mathematical Society), is mainly focused on the issue of stability of periodic orbits in no-slip planar billiards. We prove Lyapunov stability of periodic orbits in polygonal billiards of this kind and, for general billiards domains, we obtain curvature thresholds for linear stability at commonly occurring period-2 orbits. More specifically, we prove that: (i) for billiard domains in the plane having piecewise smooth boundary and at least one corner of inner angle less than π, no-slip billiard maps admit elliptic period-2 orbits; (ii) polygonal no-slip billiards under this same corner angle condition always contain small invariant neighborhoods of the periodic point on which, up to smooth conjugacy, orbits of the return map lie on concentric circles; in particular the system cannot be ergodic with respect to the canonical invariant billiard measure; (iii) the no-slip version of the Sinai billiard must contain linearly stable periodic orbits of period 2 and, more generally, we obtain a curvature threshold at which the period-2 orbits go from being hyperbolic to being elliptic; (iv) finally, we make a number of observations concerning periodic orbits in wedge and triangular billiards. Our linear stability results extend those of Wojtkowski for the no-slip Sinai billiard.
Fast imaging of filaments in the X-point region of Alcator C-Mod

Abstract A rich variety of field-aligned fluctuations has been revealed using fast imaging of D α emission from Alcator C-Mod's lower X-point region. Field-aligned filamentary fluctuations are observed along the inner divertor leg, within the Private-Flux-Zone (PFZ), in the Scrape-Off Layer (SOL) outside the outer divertor leg, and, under some conditions, at or above the X-point. The locations and dynamics of the filaments in these regions are strikingly complex in C-Mod. Changes in the filaments’ generation appear to be ordered by plasma density and magnetic configuration. Filaments are not observed for plasmas with n/n Greenwald ≲ 0.12 nor are they observed in Upper Single Null configurations. In a Lower Single Null with 0.12 ≲ n/n Greenwald ≲ 0.45 and Bx∇B directed down, filaments typically move up the inner divertor leg toward the X-point. Reversing the field direction results in the appearance of filaments outside of the outer divertor leg. With the divertor targets “detached”, filaments inside the LCFS are seen. These studies were motivated by observations of filaments in the X-point and PFZ regions in MAST, and comparisons with those observations are made.
On the probability density function of the LMS adaptive filter weights

The joint probability density function of the weight vector in least-mean-square (LMS) adaptation is studied for Gaussian data models. An exact expression is derived for the characteristic function of the weight vector at time n+1, conditioned on the weight vector at time n. The conditional characteristic function is expanded in a Taylor series and averaged over the unknown weight density to yield a first-order partial differential-difference equation in the unconditioned characteristic function of the weight vector. The equation is approximately solved for small values of the adaption parameter and the weights are shown to be jointly Gaussian with time-varying mean vector and covariance matrix given as the solution to well-known difference equations for the weight vector mean and covariance matrix. The theoretical results are applied to analyzing the use of the weights in detection and time delay estimation. Simulations that support the theoretical results are also presented. >
Conservative Uncertainty Estimation in Map-Based Vision-Aided Navigation

In a vision-aided autonomous system, it is crucial to have a consistent covariance matrix of the navigation solution. Overconfidence in covariance could lead to significant deviation of the navigation solution and failures of autonomous missions, especially in a global positioning system-denied environment. Consistency of a map-based vision-aided navigation system is investigated in this paper. As has been shown in numerous previous works, the traditional extended Kalman filter (EKF) approach to navigation produces significantly inconsistent (overconfident) covariance estimates. Covariance intersection and adjusted EKF approaches can both help to resolve the overconfidence problem. We present both simulation-based and real-world results of each of these approaches and investigate the consistency of their solutions.
A study of HSM based key protection in encryption file system

Encryption file system is designed to protect sensitive data stored on storage media. However, file encryption key is normally saved in memory with plaintext in the current known solutions. This brings potential security vulnerability such as the cold boot attack which can steal the file encryption key and in the end the encrypted file can be decrypted by the stolen key. This paper studies the current widely used encryption file systems, and proposes a key protection solution based on the Hardware Security Module (HSM) and our experiment on top of Linux Ext4 file system.
Sustainable development as a power/knowledge system: the problem of ‘governmentality’

This chapter questions the ideas and actions of one of the most unquestioned environmental movements now operating all over the world, namely, groups supporting the goal of ‘sustainable development’. One must wonder about concepts like sustainable development. Some will take sustainable development to mean ecologically sustainable.1 Others can just as rightly see it as economically sustainable, technologically sustainable or politically sustainable.2 Consequently, chambers of commerce and ministries of industry in the 1990s glibly appropriate sustainable development discourse as their own: this dam, that factory, these highways, those powerlines must be built to sustain, not nature, but job creation, population growth, industrial output or service delivery, because such elements improve human life and enhance its ecosystems’ carrying capacities. This construction, however, clashes with more ecological interpretations of sustainability in which humans allegedly are seeking ‘social and material progress within the constraints of sustainable resource use and environmental management’ and, as a result, renewable resources (plants, trees, animals and soil) will be used no faster than they are generated; non-renewable resources (such as fossil fuels and metals) will be used no faster than acceptable substitutes can be found; and pollutants will be generated no faster than can be absorbed and neutralized by the environment.3
Failure mechanisms of air entrainment in drop impact on lubricated surfaces

Lubricated surfaces have recently been introduced and studied due to their potential benefit in various configurations and applications. Combining the techniques of total internal reflection microscopy and reflection interference microscopy, we examine the dynamics of an underlying air film upon drop impact on a lubricated substrate where the thin liquid film is immiscible to the drop. In contrast to drop impact on solid surfaces where even the smallest asperities cause random breakup of the entraining air film, we report two air film failure mechanisms on lubricated surfaces. In particular, using ≈5 μm thick liquid films of high viscosity, which should make the substrate nearly atomically smooth, we show that air film rupture shifts from asperity-driven to a controlled event. At low Weber numbers (We 10), the air film failure occurs much earlier in time at the first inflection point of the air film shape away from the drop center, where the liquid–liquid van der Waals interactions become important. The predictable failure modes of the air film upon drop impact sheds light on droplet deposition in applications such as lubricant-infused self-cleaning surfaces.
How the JOBS Act is Reshaping IPOs: Implications for Entrepreneurial Firms

The Jumpstart Our Business Startups (JOBS) Act was signed into law on April 5, 2012. A key objective of the JOBS Act was to allow new ventures in the United States to go public and raise growth cap...
On the validity of the guiding-center approximation in the presence of strong magnetic gradients

The motion of a charged particle in a nonuniform straight magnetic field with a constant magnetic-field gradient is solved exactly in terms of elliptic functions. The connection between this problem and the guiding-center approximation is discussed. It is shown that, for this problem, the predictions of higher-order guiding-center theory agree very well with the orbit-averaged particle motion and hold well beyond the standard guiding-center limit ϵ≡ρ/L≪1, where ρ is the gyromotion length scale and L is the magnetic-field gradient length scale.
Do PCAOB Inspections Improve the Quality of Internal Control Audits

We investigate whether Public Company Accounting Oversight Board (PCAOB) inspections affect the quality of internal control audits. Our research design improves on prior studies by exploiting both cross-sectional and time-series variation in the content of PCAOB inspection reports, while also controlling for audit firm and year fixed effects, effectively achieving a difference-in-differences research design. We find that when PCAOB inspectors report higher rates of deficiencies in internal control audits, auditors respond by increasing the issuance of adverse internal control opinions. We also find that auditors issue more adverse internal control opinions to clients with concurrent misstatements, who thus genuinely warrant adverse opinions. We further find that higher inspection deficiency rates lead to higher audit fees, consistent with PCAOB inspections prompting auditors to undertake costly remediation efforts. Taken together, our results are consistent with the PCAOB inspections improving the quality of internal control audits by prompting auditors to remediate deficiencies in their audits of internal controls.
Initial Experiences with a CS + Law Introduction to Computer Science (CS 1)

We present the curriculum, pilot offering, and initial evaluation of a CS + Law based CS 1 course that was team taught by a Computer Science professor and a law school professor. Relevant legal topics were interwoven through the course. The results from this initial offering suggest that this sort of highly interdisciplinary offering can be successful both in computing education and in making students realize the relevance of Computer Science to the broader world beyond IT.
Unreliable collaborators: Coordination in distributed volunteer teams

I propose to study the coordination mechanisms used by teams of distributed volunteers involved in Free, Libre and Open Source Software (FLOSS) development, which has been successful despite the dual challenges of computer mediated distributed work and volunteer management. There is an opportunity to understand how the motivations of participants affect the manner in which they organize their work and to learn from their success. I propose to conduct a case study of a FLOSS project that has collaborated in each of four modes made of volunteer/nonvolunteer and distributed/collocated axes. Drawing on archives and interviews, I will use coordination theory process mapping to describe the coordination mechanisms and sequence analysis to test for differences between the four settings. Participant observation and a literature review reveal examples of novel coordination mechanisms that seem especially associated with distributed volunteers. These are dependency minimization and ‘post-hoc’ coordination, where the group acts to integrate individually chosen contributions. A possible explanation of the use of such mechanisms is that partners expect each other to be unreliable and have developed mechanisms to facilitate effective collaboration in the face of that challenge. It is hoped that these novel mechanisms will be useful to those seeking to draw on unreliable collaboration partners in an effective and scalable manner, including research and development teams, some scientific collaborations and networks of small firms collaborating without formal contract arrangements.
Dynamic Index Tracking and Risk Exposure Control Using Derivatives

We develop a methodology for index tracking and risk exposure control using financial derivatives. Under a continuous-time diffusion framework for price evolution, we present a pathwise app...
Teaching Undergraduates How to Analyze

Analysis is typically listed in taxonomies of higher order thinking. Academics consider these taxonomies worthwhile, but they are hard to teach and we are apt to ignore them. Today higher education is criticized for “dumbing down” curriculum or lowering standards. To rectify this, many policies at the state or national level are requiring higher education institutions to change. In K-12 education, Race to the Top and Common Core requirements are placing new demands on K-12 teacher preparation, which include evaluation of the analysis skills of pre-service teachers. But professors do not always view their disciplines as the proper place for teaching analytical skills. Others become frustrated when trying to teach analysis. But if we do not teach these skills, our teacher candidates will be poorly prepared for success, a problem which will cascade throughout our society, rendering our citizens less educated. In this paper, we describe our efforts to teach analysis in two courses from widely differing subject areas, literacy and mathematics education. We are now requiring teacher candidates to analyze simulated or actual samples of student work. We have developed a sequenced process of analysis education that we believe can be generalized to many other courses.
Dynamic impact of uncertainty on R&D cooperation formation and research performance: Evidence from the bio-pharmaceutical industry

Abstract Our study concentrates on the dynamic research and development (R&D) process in the pharmaceutical industry, which is characterized by high uncertainty and a low probability of success in passing research phases. We evaluate whether R&D cooperations are appropriate instruments to help firms counter various types of uncertainty in different R&D markets and across the drug development process. Our study uses a novel and comprehensive database on the pharmaceutical industry that tracks firms’ drug pipelines, R&D success rates, new drugs launched on the market and the formation of R&D cooperations throughout different research phases and research (therapeutic) markets from 1990 to 2011. We provide interesting and insightful results regarding technological, demand and profit uncertainty and their impacts on R&D cooperation formation across the drug development process. For example, we find that technological, demand and profit uncertainty vary drastically across R&D markets, and most types of uncertainty are significantly higher in the early research phase than in the late research phase. R&D cooperations are formed at the early stage of the R&D process to counter high technological, demand and profit uncertainty and to increase the likelihood of successfully passing drug development phases. In contrast, R&D cooperations formed at the late stage of the R&D process are less motivated by these types of uncertainty and more motivated by R&D funding scarcity. Our calculation shows that an early-stage R&D cooperation would increase life expectancy for the U.S. population by 2.6 million years and a late-stage R&D cooperation would decrease life expectancy by 56,000 years.
Transsphenoidal Stereotaxic Cryohypophysectomy for the Management of Pain in Disseminated Prostatic Carcinoma

Nineteen adult males with disseminated carcinoma of the prostate gland associated with intractable pain were subjected to a transsphenoidal stereotaxic cryohypophysectomy. Growth hormone (GH) assays following insulin-induced hypoglycemia were obtained once during the preoperative and twice during the postoperative period. In the postoperative assays, a 73% or greater suppression of GH levels correlated with significant clinical remission and extended survival. In all patients who had as much as 73% reduction in GH level, pain relief occurred within 4 days or less after surgery. This study shows that subtotal hypophysectomy may be adequate to achieve satisfactory clinical remission and pain control. GH assay is a useful index of the adequacy of hypophysectomy.
Meningomyelocele and Hirschprung Disease: Theoretical and Clinical Significance

Evidence to support a unifying theory to explain the embryogenesis of numerous midline anomalies, including neural tube defects, has been widely sought.1,2 The impetus for this search has been the finding of certain combinations of these anomalies at incidence rates higher than those predictable by chance,1,2 such as the occurrence of oral clefts with neural tube defects,1 or Hirschprung disease with neuroblastoma.2 To further document the possible midline developmental relationship, we present the first reported case of Hirschprung disease occurring in a patient with meningomyelocele and hydrocephalus. CASE REPORT
Pathogenesis and Clinical Course of Mixed Calcium Oxalate and Uric Acid Nephrolithiasis

By direct measurement, urine from patients who form calcium oxalate stones was supersaturated abnormally with respect to calcium oxalate monohydrate but not supersaturated with respect to undissociated uric acid. Urine from patients who form uric acid stones was supersaturated excessively with undissociated uric acid but not calcium oxalate. Patients who form both calcium oxalate and uric acid stones, however, produce urine that is supersaturated with respect to both solid phases. Low urine pH was the primary factor that increased supersaturation with respect to undissociated uric acid. The formation of both calcium oxalate and uric acid stones appears to be explained by a dual abnormality of urine supersaturation.
Dietary Factors for Cancer of Specific Sites

Epidemiologic studies have linked cancers at different sites to dietary and nutritional factors. Geographic variations in the incidence of cancer suggest that western dietary culture is associated with greater rates of some cancers and lesser rates of others. Some studies suggest that the vitamin contents of fruits and vegetables play a protective role in cancers of epithelial sites. Dietary fat is suspected as a promoter of cancer of the breast, colon, and prostate. The interactions of diet and cancer are varied and complex, and few specific recommendations are possible.
To Pex or Not to Pex

There is little agreement as to the performance of an exploration and orchiopexy on the asymptomatic side when the neonate is found to have unilateral extravaginal torsion of the testis. If extravaginal torsion does not present bilaterally, many surgeons feel that the uninvolved testis is not at risk. Extravaginal torsion of the testis, fortunately, is a rare problem. Armed with the knowledge of this case report and one previous case report, however, it is clear that extravaginal torsion can present as separate and asynchronous events. Knowledge of this fact should stimulate surgeons to explore and pex the contralateral side upon finding extravaginal torsion of the testis.
Land productivity and plot size: Is measurement error driving the inverse relationship?

This paper revisits the decades-old puzzle of the inverse plot-size productivity relationship, which states that land productivity decreases as plot size increases. Existing empirical studies on the inverse plot-size productivity relationship define land productivity or yields as self-reported production divided by plot size. This paper considers an alternative approach to estimating yields based on crop cuts. The crop-cut method entails measuring and harvesting randomly selected subplots by trained technicians, and is recommended by the Food and Agriculture Organization for the accurate measurement of crop production. Using data representative of rural Ethiopia, the analysis indicates that the inverse relationship is strong when based on self-reported production, but disappears when based on crop-cut estimates. The inference from these findings is that the inverse relationship is an artifact of systematic overreporting of production by farmers on small plots, and underreporting on larger plots. The paper also discusses how rejecting the inverse plot-size productivity relationship has significant implications for the inverse farm-size productivity relationship.
Effect of Potassium Depletion on Two-Kidney, One-Clip Renovascular Hypertension in the Rat

Effect of potassium depletion on two-kidney, one-clip renovascular hypertension in the rat. There is considerable controversy about the hemodynamic effect of potassium in hypertension. To determine if K depletion could alter the control of blood pressure, studies were performed in rats with 2-kidney, 1-clip renovascular hypertension (RVH) after 3 to 6 wks of severe and moderate K depletion. After application of a 0.23mm clip to the left renal artery, rats were placed on a K-replete (KR) (240 mEq/kg), a moderately K-depleted (KDM) (59 mEq/kg), or a severely K-depleted (KDS) (5 mEq/kg) diet. After 3 wks, mean arterial pressure (MAP) reached 154 ± 3 in KR but only 121 ± 2 in KDM (P -1 · kg -1 (P To determine if K depletion could reverse established hypertension, rats with RVH were continued on the KR diet or changed to the K-depleted diet. After 3 wks, systolic pressure was 161 ± 6 in KR but only 119 ± 4 in KDM, and 120 ± 5mm Hg in KDS (both K
Intermittent Testicular Torsion

Testicular torsion is the most common cause of acute scrotal pain in prepubertal and adolescent boys and should be foremost in the minds of primary care physicians evaluating these children. Intermittent testicular torsion is a separate entity that should be considered in all young males with a history of scrotal pain and swelling. Acute and intermittent sharp testicular pain and scrotal swelling, interspersed with long intervals without symptoms, are characteristic. Physical findings may include horizontal or very mobile testes, an anteriorly located epididymis, or bulkiness of the spermatic cord from partial twisting. Awareness of this entity and early elective orchiopexy will improve testicular salvage in patients with intermittent testicular torsion.
Embolic Tubular Epithelial Cells in Percutaneous Renal Biopsies

Four percutaneous renal biopsies with intravascular embolic tubular epithelial cells are presented. This unusual finding is presumably the result of the needle biopsy procedure and can be a puzzling and misleading artifact. It is postulated that dislodged tubular epithelial cells are pushed forward into or pulled back into punctured intrarenal arteries and subsequently transported to distant glomeruli.
Transmission Electron Microscopy and Serial Sections for Light Microscopy From the Same Block in Routine Renal Pathology

Routine serial sections for light microscopy (LM) from one sample and transmission electron microscopy (TEM) from selected areas of another sample are current procedures in renal pathology. At the present time, there are methods available to perform high-resolution light microscopy (HRLM) and TEM from the same block. However, this technology is not directly applicable or convenient for routine renal biopsies. Most methods presently available to obtain TEM studies from different areas of the same large HRLM block use reembedding methods, which considerably delay TEM studies, or mesa technics that fragment and waste the original block. Present methods to obtain serial sections from plastic blocks have been used in plant and animal morphology and need to be modified for renal pathology. In the present article, the authors present a technic that produces immediate TEM sections from different areas of the same HRLM block. This method does not produce fragmentation or waste of the original block, and TEM sections are obtained within two hours after large HRLM sections are screened. The latter sections are mounted serially on a regular microscopic slide on 8-15 separate wells painted with water-repellent ink. The methods are simple and produce large HRLM and TEM sections in 24 hours, avoiding separate samples for LM and TEM studies.
Why Deep Neural Networks for Function Approximation

Recently there has been much interest in understanding why deep neural networks are preferred to shallow networks. We show that, for a large class of piecewise smooth functions, the number of neurons needed by a shallow network to approximate a function is exponentially larger than the corresponding number of neurons needed by a deep network for a given degree of function approximation. First, we consider univariate functions on a bounded interval and require a neural network to achieve an approximation error of $\varepsilon$ uniformly over the interval. We show that shallow networks (i.e., networks whose depth does not depend on $\varepsilon$) require $\Omega(\text{poly}(1/\varepsilon))$ neurons while deep networks (i.e., networks whose depth grows with $1/\varepsilon$) require $\mathcal{O}(\text{polylog}(1/\varepsilon))$ neurons. We then extend these results to certain classes of important multivariate functions. Our results are derived for neural networks which use a combination of rectifier linear units (ReLUs) and binary step units, two of the most popular type of activation functions. Our analysis builds on a simple observation: the multiplication of two bits can be represented by a ReLU.
Space and time variability of the Southern Ocean carbon budget

The upper ocean dissolved inorganic carbon (DIC) concentration is regulated by advective and diffusive transport divergence, biological processes, freshwater and air-sea CO2 fluxes. The relative importance of these mechanisms in the Southern Ocean is uncertain, as year-round observations in this area have been limited. We use a novel physical-biogeochemical state estimate of the Southern Ocean to construct a closed DIC budget of the top 650 m and investigate the spatial and temporal variability of the different components of the carbon system. The dominant mechanisms of variability in upper ocean DIC depend on location and time and space scales considered. Advective transport is the most influential mechanism and governs the local DIC budget across the 10 day to 5-year timescales analyzed. Diffusive effects are nearly negligible. The large-scale transport structure is primarily set by up- and downwelling, though both the lateral ageostrophic and geostrophic transports are significant. In the Antarctic Circumpolar Current, the carbon budget components are also influenced by the presence of topography and biological hot spots. In the subtropics, evaporation and air-sea CO2 flux primarily balances the sink due to biological production and advective transport. Finally, in the subpolar region sea ice processes, which change the seawater volume and thus the DIC concentration, compensate the large impact of the advective transport and modulate the timing of biological activity and air-sea CO2 flux.
Is perpendicular magnetic anisotropy essential to all-optical ultrafast spin reversal in ferromagnets?

All-optical spin reversal presents a new opportunity for spin manipulations, free of a magnetic field. Most of all-optical-spin-reversal ferromagnets are found to have a perpendicular magnetic anisotropy (PMA), but it has been unknown whether PMA is necessary for spin reversal. Here we theoretically investigate magnetic thin films with either PMA or in-plane magnetic anisotropy (IMA). Our results show that spin reversal in IMA systems is possible, but only with a longer laser pulse and within a narrow laser parameter region. Spin reversal does not show a strong helicity dependence where the left- and right-circularly polarized light lead to the identical results. By contrast, the spin reversal in PMA systems is robust, provided both the spin angular momentum and laser field are strong enough while the magnetic anisotropy itself is not too strong. This explains why experimentally the majority of all-optical spin-reversal samples are found to have strong PMA and why spins in Fe nanoparticles only cant out of plane. It is the laser-induced spin–orbit torque that plays a key role in the spin reversal. Surprisingly, the same spin–orbit torque results in laser-induced spin rectification in spin-mixed configuration, a prediction that can be tested experimentally. Our results clearly point out that PMA is essential to spin reversal, though there is an opportunity for in-plane spin reversal.
Back to Buchanan? Explorations of welfare and subjectivism in behavioral economics

In light of behavioral findings regarding inconsistent individual decision-making, economists have begun to re-conceptualize the notion of welfare. One prominent account is the preference purificat...
Radiation-induced lung toxicity in non-small-cell lung cancer: Understanding the interactions of clinical factors and cytokines with the dose-toxicity relationship.

Abstract Background and purpose Current methods to estimate risk of radiation-induced lung toxicity (RILT) rely on dosimetric parameters. We aimed to improve prognostication by incorporating clinical and cytokine data, and to investigate how these factors may interact with the effect of mean lung dose (MLD) on RILT. Materials and methods Data from 125 patients treated from 2004 to 2013 with definitive radiotherapy for stages I-III NSCLC on four prospective clinical trials were analyzed. Plasma levels of 30 cytokines were measured pretreatment, and at 2 and 4 weeks midtreatment. Penalized logistic regression models based on combinations of MLD, clinical factors, and cytokine levels were developed. Cross-validated estimates of log-likelihood and area under the receiver operating characteristic curve (AUC) were used to assess accuracy. Results In prognosticating grade 3 or greater RILT by MLD alone, cross-validated log-likelihood and AUC were −28.2 and 0.637, respectively. Incorporating clinical features and baseline cytokine levels increased log-likelihood to −27.6 and AUC to 0.669. Midtreatment cytokine data did not further increase log-likelihood or AUC. Of the 30 cytokines measured, higher levels of 13 decreased the effect of MLD on RILT, corresponding to a lower odds ratio for RILT per Gy MLD, while higher levels of 4 increased the association. Conclusions Although the added prognostic benefit from cytokine data in our model was modest, understanding how clinical and biologic factors interact with the MLD-RILT relationship represents a novel framework for understanding and investigating the multiple factors contributing to radiation-induced toxicity.
Observing individual dynamic choices of activity chains from location-based crowdsourced data

Abstract The existing efforts on studying human mobility and activity using location-based crowdsourced data mainly focus on obtaining the activity chain pattern in a region at an aggregate level. To observe individual dynamic choices of activity chains, this paper presents a data-driven approach to estimating individual-specific activity chain set and corresponding choice probabilities for a given person over a 24-h period using crowdsourced data from location-based service apps. We detect an individual-specific stochastic activity set using a contextual-parcel data analysis. Based on the time geography theory, we refine a space-time bicone concept to construct an activity-travel space-time-state network from the stochastic activity set. These space-time bicone constraints define a set of potential activity choices to reduce the search space of activity location and duration choices. We construct an activity state transition graph from the space-time-state network and calculate a Markov matrix for activity choice probabilities. Furthermore, we calculate the probabilities of activity chain choices using the Markov matrix. We also visualize individual-specific activity chain set in a space-time-state network to show the dynamic choices of individual daily mobility and activity. We demonstrate the proposed approach through conducting numerical analyses using crowdsourced data from location-based service apps - Foursquare and Twitter to construct individual-specific activity choice sets and corresponding choice probabilities.
Efficacy of Lactic Acid, Lactic Acid-Acetic Acid Blends, and Peracetic Acid To Reduce Salmonella on Chicken Parts under Simulated Commercial Processing Conditions

The poultry processing industry has been undergoing a series of changes as it modifies processing practices to comply with new performance standards for chicken parts and comminuted poultry products. The regulatory approach encourages the use of intervention strategies to prevent and control foodborne pathogens in poultry products and thus improve food safety and protect human health. The present studies were conducted to evaluate the efficacy of antimicrobial interventions for reducing Salmonella on inoculated chicken parts under simulated commercial processing conditions. Chicken pieces were inoculated by immersion in a five-strain Salmonella cocktail at 6 log CFU/mL and then treated with organic acids and oxidizing agents on a commercial rinsing conveyor belt. The efficacy of spraying with six different treatments (sterile water, lactic acid, acetic acid, buffered lactic acid, acetic acid in combination with lactic acid, and peracetic acid) at two concentrations was evaluated on skin-on and skin-off chicken thighs at three application temperatures. Skinless chicken breasts were used to evaluate the antimicrobial efficacy of lactic acid and peracetic acid. The color stability of treated and untreated chicken parts was assessed after the acid interventions. The lactic acid and buffered lactic acid treatments produced the greatest reductions in Salmonella counts. Significant differences between the control and water treatments were identified for 5.11% lactic acid and 5.85% buffered lactic acid in both skin-on and skin-off chicken thighs. No significant effect of treatment temperature for skin-on chicken thighs was found. Lactic acid and peracetic acid were effective agents for eluting Salmonella cells attached to chicken breasts.
DNA Nanotechnology: A foundation for Programmable Nanoscale Materials

DNA nanotechnology is a materials design paradigm in which synthetic nucleic acids are used to program the structure and dynamics of nanometer-scale devices and materials. Driven by the convergence of decreasing DNA synthesis costs, advanced yet easy-to-use computational design and analysis tools, and, most importantly, a myriad of innovative studies demonstrating DNA’s extraordinary power to organize functional materials, DNA nanotechnology is spreading into diverse areas of traditional materials science. To further promote the integration of DNA nanotechnology into materials science, this issue of MRS Bulletin provides an overview of the unique capabilities offered by DNA nanotechnology, a set of practical techniques that make it accessible to a broad audience, and a vision for its future applications, described by international leaders in the field.
Fundamental Limits of Coded Caching: From Uncoded Prefetching to Coded Prefetching

In order to characterize the fundamental limit of the tradeoff between the amount of cache memory and the delivery transmission rate of multiuser caching systems, various coding schemes have been proposed in the literature. These schemes can largely be categorized into two classes, namely uncoded prefetching schemes and coded prefetching schemes. While uncoded prefetching schemes in general offer order-wise optimal performance, coded prefetching schemes often have better performance at the low cache memory regime. The significant differences in the coding components between the two classes may leave the impression that they are largely unrelated. In this paper, we provide a connection between the uncoded prefetching scheme proposed by Maddah Ali and Niesen (and its improved version by Yu et al. ) and the coded prefetching scheme proposed by Tian and Chen. A critical observation is made, where a coding component in the Tian–Chen scheme can be replaced by a binary code, which enables us to view the two schemes as the extremes of a more general scheme. An explicit example is given to show that the intermediate operating points of this general scheme can provide new memory-rate tradeoff points previously not known to be achievable in the literature. This new general coding scheme is then presented and analyzed rigorously, which yields a new inner bound to the memory-rate tradeoff for the caching problem.
¿Consumidores o ciudadanos? Prácticas de consumo cultural de los inmigrantes latinoamericanos en España

This paper analyzes cultural practices of Latin American immigrants in Spain. Based on surveys and in-depth interviews, it analyzes dynamics and characteristics of communication and cultural consumption, diasporic practices and intersections between local and global synergies on transnational contexts
The Non-Coding Regulatory RNA Revolution in Archaea

Small non-coding RNAs (sRNAs) are ubiquitously found in the three domains of life playing large-scale roles in gene regulation, transposable element silencing and defense against foreign elements. While a substantial body of experimental work has been done to uncover function of sRNAs in Bacteria and Eukarya, the functional roles of sRNAs in Archaea are still poorly understood. Recently, high throughput studies using RNA-sequencing revealed that sRNAs are broadly expressed in the Archaea, comprising thousands of transcripts within the transcriptome during non-challenged and stressed conditions. Antisense sRNAs, which overlap a portion of a gene on the opposite strand (cis-acting), are the most abundantly expressed non-coding RNAs and they can be classified based on their binding patterns to mRNAs (3' untranslated region (UTR), 5' UTR, CDS-binding). These antisense sRNAs target many genes and pathways, suggesting extensive roles in gene regulation. Intergenic sRNAs are less abundantly expressed and their targets are difficult to find because of a lack of complete overlap between sRNAs and target mRNAs (trans-acting). While many sRNAs have been validated experimentally, a regulatory role has only been reported for very few of them. Further work is needed to elucidate sRNA-RNA binding mechanisms, the molecular determinants of sRNA-mediated regulation, whether protein components are involved and how sRNAs integrate with complex regulatory networks.
Impact response in polymer composites from embedded optical fibers

This study investigates the feasibility of using embedded optical fibers in polymer matrix composite laminates to characterize delaminations caused by low-velocity impacts with energies between 30 ...
The Decline of Informed Trading in the Equity and Options Markets

Reliable excess returns from active portfolio management derive from informed trading. This article investigates the information content of informed trading in the equity market and the options market. The authors find that informed equity trading and options trading are positively correlated in the time series but virtually uncorrelated cross sectionally. Portfolio-level and stock-level analyses provide robust evidence that the cross-sectional return predictive power of informed trading in each market is distinct. Time-series analyses indicate that aggregate informed options trading is useful for predicting market returns but that the amount of informed trading has declined significantly in more recent years. The time-series patterns of both informed trading measures coincide closely with the decline in equity hedge fund excess returns.
The Glycolytic Enzyme Phosphofructokinase-1 Assembles into Filaments

Despite abundant knowledge of the regulation and biochemistry of glycolytic enzymes, we have limited understanding on how they are spatially organized in the cell. Emerging evidence indicates that nonglycolytic metabolic enzymes regulating diverse pathways can assemble into polymers. We now show tetramer- and substrate-dependent filament assembly by phosphofructokinase-1 (PFK1), which is considered the "gatekeeper" of glycolysis because it catalyzes the step committing glucose to breakdown. Recombinant liver PFK1 (PFKL) isoform, but not platelet PFK1 (PFKP) or muscle PFK1 (PFKM) isoforms, assembles into filaments. Negative-stain electron micrographs reveal that filaments are apolar and made of stacked tetramers oriented with exposed catalytic sites positioned along the edge of the polymer. Electron micrographs and biochemical data with a PFKL/PFKP chimera indicate that the PFKL regulatory domain mediates filament assembly. Quantified live-cell imaging shows dynamic properties of localized PFKL puncta that are enriched at the plasma membrane. These findings reveal a new behavior of a key glycolytic enzyme with insights on spatial organization and isoform-specific glucose metabolism in cells.
Anatomical Priors in Convolutional Networks for Unsupervised Biomedical Segmentation

We consider the problem of segmenting a biomedical image into anatomical regions of interest. We specifically address the frequent scenario where we have no paired training data that contains images and their manual segmentations. Instead, we employ unpaired segmentation images that we use to build an anatomical prior. Critically these segmentations can be derived from imaging data from a different dataset and imaging modality than the current task. We introduce a generative probabilistic model that employs the learned prior through a convolutional neural network to compute segmentations in an unsupervised setting. We conducted an empirical analysis of the proposed approach in the context of structural brain MRI segmentation, using a multi-study dataset of more than 14,000 scans. Our results show that an anatomical prior enables fast unsupervised segmentation which is typically not possible using standard convolutional networks. The integration of anatomical priors can facilitate CNN-based anatomical segmentation in a range of novel clinical problems, where few or no annotations are available and thus standard networks are not trainable. The code, model definitions and model weights are freely available at http://github.com/adalca/neuron.
Bianisotropic All-dielectric Metasurfaces for Efficient Diffraction of Mid-infrared Electromagnetic Waves

We design and experimentally demonstrate a bianisotropic all-silicon metasurface that shows a near unity diffraction efficiency by implementing a 4-mode interference in the far field. Resonant and non-resonant properties of these modes and respective interaction can be mediated by sculpting meta-atoms of the metasurface.
House price, loan-to-value ratio and credit risk

Abstract Real estate transactions are often established through financing. We study the effect of financing on property prices. We show that properties can transact at prices well above their collateral values. Therefore, the commonly used loan-to-value (LTV) ratio suffers a bias that can significantly understate credit risk. This bias is exacerbated when mortgages are originated with longer terms, at higher LTV ratios, or when sellers possess stronger bargaining power. Furthermore, this bias is larger under aggressive lending products, e.g. interest-only loans and mortgages allowing negative amortization. Our simulation results suggest that many mortgages originated at the peak of the housing bubble are, in fact, “under water” at origination. In particular, the loan amount of a 30-year mortgage at a 95% LTV can be 15% greater than the collateral value of the property, suggesting the mortgage is already deep “under water” at origination. These findings call into questions underwriting and risk control practices in mortgages and other collateralized debts.
A Fresh Look at Return Predictability Using a More Efficient Estimator

I assess time-series return predictability using a weighted least squares estimator that is around 25% more efficient than ordinary least squares (OLS) because it incorporates time-varying volatility into its point estimates. Traditional predictors, such as the dividend yield, perform better in- and out-of-sample when using my estimator, indicating the insignificant OLS estimates may be false negatives driven by a lack of power. Some newer predictors, such as the variance risk premium and the president’s political party, are insignificant when using my estimator, indicating the significant OLS estimates may be false positives driven by a few periods with high expected volatility. Received March 31, 2018; editorial decision September 26, 2018 by Editor Jeffrey Pontiff. Authors have furnished an Internet Appendix and supplementary data and code, which are available on the Oxford University Press Web site next to the link to the final published paper online.