cssi/SciSciGPT-SciSciNet huggingface dataset:
Improved algorithms for orienteering and related problems

In this article, we consider the orienteering problem in undirected and directed graphs and obtain improved approximation algorithms. The point to point-orienteering problem is the following: Given an edge-weighted graph G=(V, E) (directed or undirected), two nodes s, t ∈ V and a time limit B, find an s-twalk in G of total length at most B that maximizes the number of distinct nodes visited by the walk. This problem is closely related to tour problems such as TSP as well as network design problems such as k-MST. Orienteering with time-windows is the more general problem in which each node v has a specified time-window [R(v), D(v)] and a node v is counted as visited by the walk only if v is visited during its time-window. We design new and improved algorithms for the orienteering problem and orienteering with time-windows. Our main results are the following:— A (2+e) approximation for orienteering in undirected graphs, improving upon the 3-approximation of Bansal et al. [2004].— An O(log2 OPT) approximation for orienteering in directed graphs, where OPT ≤ n is the number of vertices visited by an optimal solution. Previously, only a quasipolynomial-time algorithm due to Chekuri and Pal [2005] achieved a polylogarithmic approximation (a ratio of O(log OPT)).— Given an α approximation for orienteering, we show an O(α c max{log OPT, log lmax/lmin}) approximation for orienteering with time-windows, where lmax and lmin are the lengths of the longest and shortest time-windows respectively.
Few are called, fewer are chosen: Elite reproduction in U.S. academic accounting

Abstract Previous work on academic accounting in the U.S. has documented impressive concentrations in publications and labor market success by faculty with credentials from a relatively small number of prestigious universities. However, this work left open the pre-doctoral origins of people producing this work, and therefore could not rule out the operation of a meritocracy. Utilizing the theoretical contributions of Bourdieu, this paper argues that elite institutions constitute a unique positioning of symbolic capital that favors a particular type of candidate over equally able others. Through systematic personnel movements into doctoral programs, elites within the discipline are able to reproduce. A study of faculty cultural capital acquired from previous matriculation at elite universities offers empirical support for these ideas. The results suggest that previous studies of concentration in academic accounting are set in motion because of this systematic selection process.
The Internet and income inequality: Socio-economic challenges in a hyperconnected society

Abstract Information and communication technologies (ICTs) influence income distribution directly and indirectly. A diverse pattern of decreases and increases in income inequality has emerged in parallel with increasing fixed and mobile connectivity. Building on earlier research, this paper develops a socio-technical model to examine the contribution of hyperconnectivity to these outcomes. ICTs rarely are a single cause but interact with other technological, economic, and political forces to shape the extent of income inequality. Depending on the constellation of these factors, income inequality may decrease or increase. Public policy may be able to ameliorate undesirable outcomes although effective programs will typically require initiatives that go beyond traditional measures designed to reduce digital divides.
Optimization-Based Design of Control Systems with Uncertain Plant

Abstract This paper presents an optimization-based design methodology for the worst case design of single-input, single-output control systems when the plant model contains both parametric and unstructured uncertainty. It is shown that computational complexity can be considerably reduced, at the expense of some tightening of the specifications, by replacing the original performance-specifying semi-infinite inequalities by simpler majorizations. The decomposition and majorization results are also used to determine whether a controller structure can satisfy a given design requirement.
The Kidney and Hypertension

• It is apparent that the kidney occupies a central role in control of arterial BP. Although a gratifying amount of information has been learned in the past several decades about the renal regulation of BP, many questions remain. However, I anticipate that with further research efforts, we will come to more completely appreciate Richard Bright's prescient observation, "I confess I am inclined to believe that the kidney is the chief promoter of the other derangements." (Arch Intern Med1982;142:1889-1895)
Systemic Hypertension Secondary to Peripheral Vascular Anomalies in Patients With Williams Syndrome

ng/ml , n = 20). Although whole blood serotonin concentrations may decrease with increasing age, 1~ values in patient 1 were also elevated compared with those in an age-matched normal pediatric population we are studying (values to be reported elsewhere). Elevated serotonin levels in children with Williams syndrome adds to the growing list of disorders that have evidence of central nervous system serotonergic dysfunction? In summary, medical, developmental, and psychologic data have been described in two children with Williams syndrome and autism. The documentation and comparison of specific abnormalities in autistic Children with different associated organic conditions may help to delineate the neurobiologic cause of both the behavioral phenotype and the underlying genetic conditions.
Acquired Cystic Disease of the Kidneys: Computed Tomography and Ultrasonography Appraisal in Patients on Peritoneal and Hemodialysis

Screening chronic hemodialysis patients (CHD) for acquired cystic disease of the kidneys (ACDK) and its complications (hemorrhage and neoplasm) has become accepted management. We evaluated patients on CHD as well as patients on chronic peritoneal dialysis (CPD) for ACDK. The kidneys of 80 chronic dialysis patients were examined by CT and real time sonography. Forty-four were hemodialysis and 36 were peritoneal dialysis patients. ACDK was found in more than 90% of both CHD and CPD patients who had been dialyzed longer than three years. Bilateral renal carcinoma was detected in one hemodialysis patient. Our results show that chronic peritoneal dialysis patients are also at risk for ACDK and its associated complications. A similar natural history for the development of ACDK in both forms of dialysis suggests that the same screening precautions should be instituted for chronic peritoneal dialysis patients.
Prognostic Role of the Intravenous Urogram in Children With Acute Leukemia

We retrospectively studied intravenous urograms (IVU) performed at presentation on 108 children with acute leukemia in order to determine whether any association existed between an abnormal IVU and known prognostic factors at presentation, initial renal function, and outcome. Sixteen patients (14%) had abnormal IVUs. These patients were compared to the remainder of the group and found to be comparable in respect to known prognostic factors at diagnosis (P greater than 0.05). No correlation was found between abnormal renal function and an abnormal IVU. Renal enlargement was associated with shorter survival only in patients who had both adenopathy and hepatosplenomegaly (P less than 0.01). This effect did not persist in any other group of patients examined. When subjected to multivariate analysis the IVU did not significantly influence relapse or survival in these patients. Renal enlargement may be a prognostic feature in some patients with childhood leukemia. Nevertheless routine evaluation by IVU is discouraged because of potential adverse affects of urographic contrast media and the availability of noninvasive ultrasound techniques.
Intracellular Escherichia Coli in Urinary Malakoplakia: A Reservoir of Infection and its Therapeutic Implications

Urinary malakoplakia may pursue an aggressive clinical course with persistent infection, despite seemingly appropriate antibiotic therapy. The authors studied seven adult females with urinary malakoplakia. Specific immunocytochemical staining demonstrated intracellular Escherichia coli in malakoplakia tissue in four patients. In two of the four patients, the bacteria were present despite antibiotic-induced sterile urines at time of biopsy. Cessation of therapy consistently lead to recurrent bacteriuria in these patients. In one such patient, the intracellular bacilli were confirmed as E. coli by culture of crushed malakoplakia tissue and electron microscopic study; the organisms were a routine E. coli strain susceptible to multiple previously administered antibiotics. Only sequential treatment with bethanechol chloride and trimethoprim-sulfamethoxazole, however, eliminated the infection; all three drugs are thought to be capable of enhancing intracellular killing of bacteria. Conventional antibiotic therapy failed to halt progression of disease in other malakoplakia patients. The data indicate that intracellular bacteria may serve as a reservoir of persistent/recurrent infection in urinary malakoplakia. Optimal therapy should include therapeutic agents that may control intracellular organisms.
Current Trends in the Incidence of Neural Tube Defects

To verify and investigate the reported decline of neural tube defects (NTDs) in the last decade, data from three different sources were examined: the Birth Defects Monitoring Program (BDMP), composed of newborn discharge diagnoses; the population-base Metropolitan Atlanta Congenital Defects Program (MACDP); and the National Center for Health Statistics (NCHS), whose data include only live births. Although the three systems use different methods of ascertaining cases, all data bases showed a decreasing trend in NTD rates, with annual percent decreases of 3.1% for NCHS, 5.7% for BDMP, and 7.7% for MACDP. The decrease was noted in all variables examined: race, sex, and birth status for each defect. NTD rates appear to be declining more rapidly in females than in males. Further, the rate among stillborn infants decreased more than the rate among live-born infants. The exclusion of stillbirths in the NCHS data may contribute to its low rate of decline for female anencephalics. Data from England showed a larger average annual decrease (10.6%) than did data from the United States. Although reasons for the overall decline are not verifiable, a variety of explanations are suggested for this decline and for the difference in NTD rate decline noted between live births and stillbirths. The overall decline in NTD rates should be investigated with respect to etiology; recognition of the decline is useful for planning and evaluating health care programs.
Chapter 11, Hydrogen Storage

Publisher Summary Each factory, office, and house derives its energy from ultra-pure hydrogen either generated in situ or brought in by reliable underground pipelines. During the day, gleaming roofs collect sunlight and generate more electricity than can be used. The excess is sent to electrolyzers and stored locally as high-pressure hydrogen to be used at night or as fuel for cooking and heating. High-precision, inexpensive oscillators keep the fuel cell generating electricity at the exact prescribed frequency, its phase updated periodically by low-frequency radio signals. When needed, additional hydrogen, from nonpolluting sources, is imported through existing pipes. The energy is very ecologically friendly. The qualities of hydrogen have been extolled by enthusiasts. Once it has been produced, one has the most ecologically friendly fuel possible. It suffers, however, from a major drawback—its extremely low density. Per cubic meter, hydrogen has but one-third of the combustion energy of methane. Nevertheless, a given pipeline has about the same power-carrying capacity with the two gases; its lower viscosity almost exactly compensates the lower specific energy of hydrogen. Thus, the bulk distribution of hydrogen should not present insurmountable problems. A more serious problem arises when hydrogen has to be supplied to a moving vehicle. One must either generate it in the vehicle itself or find a convenient way to store it onboard.
Repurposing the paving: The case of surplus residential parking in Davis, CA

Abstract The city of Davis, CA, has a rich history of high bicycling levels, and the city has ambitious transportation policies and goals. However, both the city of Davis and transportation scholars have overlooked the potential opportunities a surplus of on-street residential parking provides to cities. The existing literature on the influence of parking policy and provision has focused primarily on commercial districts and on large metropolises, neglecting parking in more purely residential areas. In this descriptive case study, we systematically observed the number of cars on a transect of residential streets in the early morning and late evening on weekdays to conservatively estimate the average peak parking demand by residents as a percentage of available parking spaces. On average, only 2 in 7 available parking spaces were occupied during peak hours. We note that the over-provision of on-street parking in residential neighborhoods could be a nexus for the city to achieve its sustainable transportation policy goals while addressing its fiscal and housing supply challenges. We discuss possible design solutions, including providing ecosystem services, implementing traffic calming measures, and creating accessory dwelling units.
Numerical Simulation of Flow and Heat Transfer in Rotating Cooling Passage With Turning Vane in Hub Region

Numerical simulation of three-dimensional turbulent flow and heat transfer was performed in a multi-pass rectangular (AR = 2:1) rotating cooling channel with and without turning vane in the hub region under various flow conditions, with two different Reynolds numbers of 10000 and 25000, two different channel orientations of 45-deg and 90-deg., and the rotation number varies from 0 to 0.2. The present study provides detailed explanation on the dramatic flow change due to the turning vane. The numerical results show that the addition of vane in hub portion does not cause much impact to the flow before the turn. However, it greatly affects flow behaviors and heat transfer characteristics in the turning region and the third passage after the hub turn. Compared to the cases without turning vane, the vane clearly changes local flow pattern, divides the main flow into two separate streams, and alters the flow reattachment location and vortex distribution. The local heat transfer is influenced by this complex flow field and its effects last from the turn portion to the third passage.© 2013 ASME
FEMORAL AND TIBIAL ROTATING BEARING SURFACE DESIGN AFFECTS KNEE STABILITY AND KINEMATICS

INTRODUCTION The intact, healthy human knee joint is stable under anterior-posterior (AP) loading but allows for substantial internal-external (IE) laxity. In vivo clinical studies of the intact knee consistently demonstrate femoral rollback with flexion (Hill et al., 2000, Dennis et al., 2005). A tri-condylar, posterior stabilized (PS) total knee arthroplasty (TKA) with a rotating platform bearing (TKA-A) has been designed to address these characteristics of the intact knee. The third condyle is designed to guide the femoral component throughout the entire flexion arc (AP stability and femoral rollback with flexion), while the rotating platform bearing allows for IE rotation. This study used a computer model to compare the AP and IE laxity of a new TKA-A to that of two clinically established TKAs (TKA-B: rotating PS TKA, TKA-C: fixed PS TKA) and to demonstrate improvements in AP stability, IE rotation, and femoral rollback. METHODS A specimen-specific, robotically calibrated computer knee model (Siggelkow et al., 2012), consisting of the femur, tibia and fibula as well as the kinetic contribution of the ligaments and capsule was virtually implanted with appropriate sizes of TKA-A, TKA-B and TKA-C adhering to the respective surgical techniques. A similar extension gap was targeted for all designs. The following kinematic data resulting from applied loads and moments were analyzed: 1) Passive AP and IE laxity (AP load: ± 50 N, IE moment: ± 6 Nm) of the midpoint between the flexion facet centers (Iwaki et al., JBJS, 2000) under low compression (44 N), 2) AP position of the medial and lateral low points (LP) of the femoral component during a lunge motion (Varadarajan et al., 2008). RESULTS The TKA-A design demonstrated decreased AP laxity compared to TKA-B and TKA-C at all evaluated flexion angles beyond full extension (Figure 1, A). Both the TKA-A and TKA-B designs demonstrated greater IE laxity than TKA-C in early and mid-flexion (Figure 1, B). Considering lunge kinematics, the TKA-A design experienced the greatest rollback (change in AP position) of both condyles throughout flexion (lateral: 13 mm, medial: 7 mm) compared to TKA-B and TKA-C (lateral: 10 mm, medial: −1 mm; lateral: 9 mm medial: 6 mm), respectively. Rollback of the lateral condyle was greater than that of the medial condyle for all designs, which is consistent with the patterns reported for the intact knee (Hill et al., 2000, Dennis et al., 2005). Furthermore, the rate of rollback was more consistent for TKA-A compared to TKA-B and TKA-C. CONCLUSION The new tri-condylar TKA design exhibited greater AP stability at all flexion angles and greater IE laxity through mid-flexion compared to two clinically-established TKA designs. In addition, posterior femoral rollback was more continuous for this new design. We attribute these findings to the design of the third condyle and the rotating platform bearing. For any figures or tables, please contact authors directly (see Info & Metrics tab above).
Expanded flow rate range of high-resolution nanoDMAs via improved sample flow injection at the aerosol inlet slit

Abstract High-resolution DMAs requiring hundreds of l/min of sheath gas flow Q to classify 1 nm particles have not been previously examined and optimized under the modest Q values (tens of l/min) needed to classify particles well above 10 nm. Here we study the resolving power ℛ (based on the relative width of the transfer function) of the Halfmini DMA, at sample flow rates q >1 l/min. The charge-reduced electrosprayed ovalbumin protein used as test aerosol has an accurately determinable Gaussian mobility distribution, which limits the measurable ℛ to at most 25–30. Non-ideal DMA response can however be precisely probed by comparing measured peak widths with the convolution of the protein's mobility distribution with the triangular Knutson-Whitby distribution associated to the finite qi/Q ratio. For the unmodified Halfmini DMA, ℛ departs considerably from ideal at qi/Q values as modest as 2%, revealing a problem with the aerosol inlet flow. This imperfection is not removed by either increasing or decreasing the slit width, nor by reorienting axially the sample flow jet as it merges with the sheath gas. By introducing a ring with many perforations upstream of the inlet slit, which favors a more symmetric distribution of the sample flow over the slit perimeter, ℛ values close to ideal are approached with qi/Q ratios as large as 6–12%. This improvement enables (in principle) classification of particles larger than 30 nm.
Time and Other Considerations in Mediation Design

This article serves as a practical guide to mediation design and analysis by evaluating the ability of mediation models to detect a significant mediation effect using limited data. The cross-sectional mediation model, which has been shown to be biased when the mediation is happening over time, is compared with longitudinal mediation models: sequential, dynamic, and cross-lagged panel. These longitudinal mediation models take time into account but bring many problems of their own, such as choosing measurement intervals and number of measurement occasions. Furthermore, researchers with limited resources often cannot collect enough data to fit an appropriate longitudinal mediation model. These issues were addressed using simulations comparing four mediation models each using the same amount of data but with differing numbers of people and time points. The data were generated using multilevel mediation models, with varying data characteristics that may be incorrectly specified in the analysis models. Models were evaluated using power and Type I error rates in detecting a significant indirect path. Multilevel longitudinal mediation analysis performed well in every condition, even in the misspecified conditions. Of the analyses that used limited data, sequential mediation had the best performance; therefore, it offers a viable second choice when resources are limited. Finally, each of these models were demonstrated in an empirical analysis.
Complementary or Conflictual? Formal Participation, Informal Participation, and Organizational Performance

Most studies of worker participation examine either formal participatory structures or informal participation. Yet, increasingly, works councils and other formal participatory bodies are operating in parallel with collective bargaining or are filling the void left by its decline. Moreover, these bodies are sprouting in workplaces in which workers have long held a modicum of influence, authority, and production- or service-related information. This study leverages a case from the health care sector to examine the interaction between formal and informal worker participation. Seeking to determine whether or not these two forces—each independently shown to benefit production or service delivery—complement or undermine one another, we find evidence for the latter. In the case of the 27 primary care departments that we study, formal structures appeared to help less-participatory departments improve their performance. However, these same structures also appeared to impede those departments with previously high levels of informal participation. While we remain cautious with respect to generalizability, the case serves as a warning to those seeking to institute participation in an environment in which some workers have long felt they had the requisite authority, influence, and information necessary to perform their jobs effectively.
TARS: A Traffic-Adaptive Receiver-Synchronized MAC Protocol for Underwater Sensor Networks

Efficient medium access control (MAC) is desirable for underwater sensor networks (UWSNs). However, designing an efficient underwater MAC protocol is challenging due to the long propagation delay of the underwater acoustic channel and spatial-temporal uncertainty. In this article, we propose a novel Traffic-Adaptive Receiver-Synchronized underwater MAC protocol, TARS, for throughput maximization. We divide time into equal-sized slots, each the size of one packet transmission time plus a guard time to cope with network dynamics. We adjust the packet transmission phase in a slot, determined by the sender-receiver distance, to align packet receptions for collision reduction. Both the sound propagation speed variation and the node mobility are considered in setting the transmission phase and slot size. We employ a queue-aware utility-optimization framework to determine the optimal transmission strategies dynamically, taking into account both the interference and data queue status. Extensive simulation results show that compared to the existing representative protocols, TARS achieves better performance with higher network throughput and lower packet delay (e.g., about 13%−146% higher in throughput and 13%−21% lower in delay than others in a mobile ad hoc network), as well as robustness under network mobility. Thus, TARS is highly suitable for mobile and traffic-varying UWSNs.
The Evolving Disclosure Landscape: How Changes in Technology, the Media, and Capital Markets Are Affecting Disclosure

Recent changes in technology and the media are causing significant changes in how capital markets assimilate and respond to information. We identify important themes in the disclosure literature and use this as a framework to discuss the conference papers that appear in this volume. These papers examine how managers’ disclosure practices are being affected by changes in technology, the media, and capital markets. While this work makes important progress, we discuss how continuing technological change and the emergence of new forms of media offer further opportunities for research on the role of disclosure in capital markets.
The Distribution of Environmental Damages

AbstractMost regulations designed to reduce environmental externalities impose costs on individuals and firms. A large and growing literature examines whether these costs are disproportionately bor...
Networked Cournot Competition in Platform Markets: Access Control and Efficiency Loss

This paper studies network design and efficiency loss in open and discriminatory access platforms under networked Cournot competition. In open platforms, every firm connects to every market, while discriminatory platforms limit connections between firms and markets to improve social welfare. We provide tight bounds on the efficiency loss of both platforms; (i) that the efficiency loss at a Nash equilibrium under open access is bounded by 3/2, and (ii) for discriminatory access platforms, we provide a greedy algorithm for optimizing network connections that guarantees efficiency loss at a Nash equilibrium is bounded by 4/3, under an assumption on the linearity of cost functions.
Simplifying choices in defined contribution retirement plan design: a case study

The growth and popularity of defined contribution pensions, along with the government's increasing attention to retirement plan costs and investment choices provided, make it important to understand how people select their retirement plan investments. This paper shows how employees in a large firm altered their fund allocations when the employer streamlined its pension fund menu and deleted nearly half of the offered funds. Using administrative data, we examine the changes in plan participant investment choices that resulted from the streamlining and how these changes might affect participants’ eventual retirement wellbeing. We show that streamlined participants’ new allocations exhibited significantly lower within-fund turnover rates and expense ratios, and we estimate this could lead to aggregate savings for these participants over a 20-year period of 9,400 per participant. Moreover, after the reform, streamlined participants’ portfolios held significantly less equity and exhibited significantly lower risks by way of reduced exposures to most systematic risk factors, compared with their non-streamlined counterparts.
Range-max queries on uncertain data

Abstract Let P be a set of n uncertain points in R d , where each point p i ∈ P is associated with a real value v i and exists with probability α i ∈ ( 0 , 1 ] independently of the other points. We present algorithms for building an index on P so that for a d -dimensional query rectangle ρ , the expected maximum value or the most-likely maximum value in ρ can be computed quickly. Our main contributions include the following: (i) The first index of sub-quadratic size to achieve a sub-linear query time in any dimension. (ii) A conditional lower bound for most-likely range-max queries, based on the conjectured hardness of the set-intersection problem. (iii) A near-linear-size index for estimating the expected range-max value within approximation factor 1/2 in O ( polylog ( n ) ) time. (iv) Extensions of our algorithm to more general uncertainty models and for computing the top- k values of the range-max.
The influence of equitable treatment on Latina/o high school students’ college aspirations

This study examined the influence of equitable treatment on Latina/o students’ college aspirations. Logistic regression was used to identify variables associated with Latina/o high school students’...
A Revisited Inquiry: A Survey of the Members of the American Rehabilitation Counseling Association (ARCA):

In recognition of the American Rehabilitation Counseling Association’s (ARCA) 60th anniversary and the need to gather and provide data to further inform the rehabilitation counseling (RC) field wit...
Are the Stock Markets “Rigged”? An Empirical Analysis of Regulatory Change

Abstract Volatile events in the stock market such as the 2010 Flash Crash have sparked concern that financial markets are “rigged” in favor of trading firms that use high frequency trading (“HFT”) systems. We analyze a regulatory change implemented by the SEC in 2007 by examining its effect on a key market metric, the bid-ask spread, an investor cost, and find that the regulatory shift, indeed, disadvantages investors. We link the implementation of this change to a shift in the volume of trades from a low-cost venue to a high-cost venue. We argue that this outcome is predicted by the incentives of the venues, non-profit stock exchanges owned by different types of members. The less-volatile, lower-cost New York Stock Exchange was owned by underwriters and included a specialist system that is less vulnerable to HFT tactics that can disadvantage investors.
XBRL Mandate and Timeliness of Financial Reporting: Do XBRL Filings Take Longer?

ABSTRACT This study examines the impact of the Securities and Exchange Commission's (SEC) XBRL (eXtensible Business Reporting Language) mandate on the timeliness of financial reporting, measured by...
Performance tests of gravity-assist heat pipes with screen-wick structures

A series of performance-limit tests were made at several operating temperatures with sodium heat pipes containing simple wicks comprised of layers of woven-wire screen. After each pipe was tested horizontally, vertical tests were conducted in a gravity-assist mode with the evaporator down. Higher heat-transfer limits were achieved in the vertical tests, but good agreement between measured and calculated limits was not always obtained. Wick imperfections, in the form of spaces between screen layers and other large openings, were beneficial during horizontal operation because they provided low-impedance flow paths for liquid return. During vertical operation, however, the openings filled with vapor and sometimes produced superheat limitations which seriously reduced heat transfer. In some tests, superheat limitations were eliminated by locating fine-mesh screen between the wick and heat-pipe wall. These tests showed that gravity-assist performance can be improved by large wick passages which are located away from the heat-pipe wall, but the passages must be arranged so they collect condensate readily and protect this condensate from the flowing vapor. Presented as Paper 74-723 at the AIAA/ASME Thermophysics and Heat Transfer Conference, Boston, Mass., July 15-17, 1974. Work performed under the auspices of the U. S. Atomic Energy Commission. ^Member of Professional Staff. tMechanical Technician. $Group Leader, Advanced Heat Transfer. 201 Purchased from American Institute of Aeronautics and Astronautics
Fibroblast growth factor 23 does not directly influence skeletal muscle cell proliferation and differentiation or ex vivo muscle contractility.

Skeletal muscle dysfunction accompanies the clinical disorders of chronic kidney disease (CKD) and hereditary hypophosphatemic rickets. In both disorders, fibroblast growth factor 23 (FGF23), a bon...
Using Pilot Systems to Execute Many Task Workloads on Supercomputers

High performance computing systems have historically been designed to support applications comprised of mostly monolithic, single-job workloads. Pilot systems decouple workload specification, resource selection, and task execution via job placeholders and late-binding. Pilot systems help to satisfy the resource requirements of workloads comprised of multiple tasks. RADICAL-Pilot (RP) is a modular and extensible Python-based pilot system. In this paper we describe RP’s design, architecture and implementation, and characterize its performance. RP is capable of spawning more than 100 tasks/second and supports the steady-state execution of up to 16K concurrent tasks. RP can be used stand-alone, as well as integrated with other application-level tools as a runtime system.
Functional degradation: A mechanism of NLRP1 inflammasome activation by diverse pathogen enzymes

Inflammasomes are multiprotein platforms that initiate innate immunity by recruitment and activation of caspase-1. The NLRP1B inflammasome is activated upon direct cleavage by the anthrax lethal toxin protease. However, the mechanism by which cleavage results in NLRP1B activation is unknown. In this study, we find that cleavage results in proteasome-mediated degradation of the amino-terminal domains of NLRP1B, liberating a carboxyl-terminal fragment that is a potent caspase-1 activator. Proteasome-mediated degradation of NLRP1B is both necessary and sufficient for NLRP1B activation. Consistent with our functional degradation model, we identify IpaH7.8, a Shigella flexneri ubiquitin ligase secreted effector, as an enzyme that induces NLRP1B degradation and activation. Our results provide a unified mechanism for NLRP1B activation by diverse pathogen-encoded enzymatic activities.
Using Low‐Frequency Earthquake Families on the San Andreas Fault as Deep Creepmeters

The central section of the San Andreas Fault hosts tectonic tremor and low-frequency earthquakes (LFEs) similar to subduction zone environments. LFEs are often interpreted as persistent regions that repeatedly fail during the aseismic shear of the surrounding fault allowing them to be used as creepmeters. We test this idea by using the recurrence intervals of individual LFEs within LFE families to estimate the timing, duration, recurrence interval, slip, and slip rate associated with inferred slow slip events. We formalize the definition of a creepmeter and determine whether this definition is consistent with our observations. We find that episodic families reflect surrounding creep over the interevent time, while the continuous families and the short time scale bursts that occur as part of the episodic families do not. However, when these families are evaluated on time scales longer than the interevent time these events can also be used to meter slip. A straightforward interpretation of episodic families is that they define sections of the fault where slip is distinctly episodic in well-defined slow slip events that slip 16 times the long-term rate. In contrast, the frequent short-term bursts of the continuous and short time scale episodic families likely do not represent individual creep events but rather are persistent asperities that are driven to failure by quasi-continuous creep on the surrounding fault. Finally, we find that the moment-duration scaling of our inferred creep events are inconsistent with the proposed linear moment-duration scaling. However, caution must be exercised when attempting to determine scaling with incomplete knowledge of scale.
The dynamics of inequality in the human story: a brief sketch

Teaching contemporary inequality can be significantly enriched by being nested in its dynamics over the course of human history. This essay provides those teaching inequality with a brief sketch of: 1) the original human condition of a high degree of equality that endured for 97% to 98% of our species' existence as foragers and early agriculturalists; 2) the origin of extreme inequality that accompanied the rise of states and civilisation about 5,500 years ago as weapons technology enabled a few to subjugate the producers; 3) why, despite a significant degree of political democracy in many contemporary societies, extreme inequality persists.
Caries lesion remineralization with fluoride toothpastes and chlorhexidine - effects of application timing and toothpaste surfactant.

Introduction Habitual toothbrushing with fluoridated toothpaste followed by rinsing with antibacterial mouthwashes is a method to maintain good oral hygiene and to diminish the occurrence and severity of dental caries and periodontal disease. However, our understanding of how antimicrobial agents in mouthwashes affect fluoride-mediated caries lesion remineralization is still poor. Objective The objectives of this in vitro study were a) to determine the effects of the waiting period of chlorhexidine (CHX) rinsing after fluoride toothpaste use and b) to further determine the effect of the type of toothpaste surfactant [sodium dodecyl sulfate (SDS) or cocamidopropyl betaine (CAPB)] on caries lesion remineralization associated with CHX rinsing. Material and methods Caries lesions were formed in bovine enamel specimens and assigned to 10 treatment groups (n=18) based on Vickers surface microhardness (VHN). Lesions were then pH-cycled for 10 days with daily regimen comprised of twice daily toothpaste slurry treatments (1150 ppm fluoride, with SDS or CAPB), followed by CHX solution treatments [0, 15, 30 or 60 minutes following slurry treatment or no CHX treatment (negative control)]. VHN was measured again and the extent of lesion remineralization calculated (∆VHN). Results ∆VHN with SDS-toothpaste was significantly lower than with CAPB-toothpaste, indicating more remineralization for the CAPB-toothpaste. ∆VHN with 0-minute waiting time was significantly lower than with 30-minute waiting time and with negative control. Conclusions The absence of CHX as an adjunct to fluoride toothpastes led to greater remineralization of enamel lesions compared with the immediate use of CHX treatment for both SDS- and CAPB-toothpastes. CAPB-toothpastes indicated significantly greater remineralization than SDS-toothpastes, and can be suggested for patients at high risk of caries. A 30-minute waiting time for CHX treatment is recommended after brushing.
XX > XY?: The changing female advantage in life expectancy

Females live a lot longer than males in most parts of the world today. But that was not always the case. We ask when and why the female advantage emerged. We show that reductions in maternal mortality and fertility are only partial reasons. Rather, the sharp reduction in infectious disease in the early twentieth century played a role. Those who survive most infectious diseases carry a health burden that affects organs and impacts general well-being. We use newly collected data from Massachusetts containing information on cause of death since 1887 to show that females between the ages of 5 and 25 were disproportionately affected by infectious diseases. Both males and females lived longer as the burden of infectious disease fell, but women were more greatly impacted. Our explanation does not tell us precisely why women live longer than men, but it does help understand the timing of their relative increase.
Digitized metamaterial absorber-based compressive reflector antenna for high sensing capacity imaging

Conventional multistatic radar systems using microwave and millimeter-wave (mm-wave) frequencies seek to reconstruct the target in the imaging domain, employing many transmitting and receiving antenna elements. These systems are suboptimal, in that they do not take into consideration the large mutual information existing between the measurements. This paper reports a new mm-wave radar system for high sensing capacity applications. The system is composed of a compressive reflector antenna (CRA), whose surface is specially tailored by digitized metamaterial absorbers (MMAs). The MMA elements are designed to have a highly frequency-dispersive response in the operating band of the radar. This enables the CRA to create highly uncorrelated spatial and spectral codes in the imaging region. A semi-analytic method based on Drude–Lorentz model is used to approximate the reflection response of the MMAs. The performance of the developed radar system is evaluated in active mm-wave sensing systems by imaging PEC scatterers and an extended human-size model in the near-field of the radar. A computational method based on physical optics is established for solving the numerical examples. For reconstructing the image using compressive sensing techniques, a norm-1 regularized iterative algorithm based on the alternating direction method of multipliers and a Nesterov-based algorithm were applied.
The Stability of Longest-Queue-First Scheduling With Variable Packet Sizes

It is well known that the MaxWeight scheduling algorithm is throughput-optimal in wireless networks. However, its complexity is exponential in the number of links in an ad hoc network. In this work, we consider a greedy variant of the MaxWeight algorithm, called Longest Queue First (LQF). A synchronous version of LQF is known to be throughput-optimal under a topological condition called local pooling. Here we study an asynchronous version of LQF which is suitable for implementation in networks with variable packet sizes. We show that asynchronous LQF is also throughput-optimal under the local pooling condition.
Imprecise and Informative: Lessons from Market Reactions to Imprecise Disclosure

Imprecise language in corporate disclosures can convey valuable information on firms’ fundamentals. We evaluate this idea by developing a linguistic imprecision measure based on sentences marked with the “weasel tag” on Wikipedia. In the 10 weeks after the 10-K disclosure, high linguistic imprecision predicts positive and non-reverting abnormal returns, improvements to stock liquidity, more insider and informed buying, and more positive news sentiment. These findings are driven by disclosures that are more forward-looking and use more R&D terms. Together, our results imply that imprecise language in 10-Ks contains new information on positive but yet immature prospects of future cash flows.
Three-Level Two-Stage Decoupled Active NPC Converter With Si IGBT and SiC MOSFET

This paper presents the operation principle and benefits of a novel power converter topology named three-level two-stage decoupled active neutral point clamped (3L-TDANPC) converter, which is implemented based on a hybrid utilization of silicon (Si) insulated gate bipolar transistors (IGBTs) and silicon carbide (SiC) metal–oxide semiconductor field-effect transistors ( mosfet s). The 3L-TDANPC converter can achieve high efficiency with limited number of SiC mosfet modules while keeping balanced loss distribution among the switching devices, which helps increase the converter power ratings. In addition, in this 3L-TDANPC converter, the SiC mosfet has a potential to ride through short-circuit fault because of the presence of Si IGBTs. The key challenges that are associated with system resonant current are investigated and the methods to damp such resonant current are proposed and explained in detail. The simulation and experimental results based on a 1-MW 3L-TDANPC converter prototype confirm the expected benefits of this proposed converter and the effectiveness of the proposed resonant current damping methods.
Preparation of Nuclear and Cytoplasmic Extracts from Mammalian Cells

Extracts prepared from the isolated nuclei of cultured cells have been instrumental in dissecting the mechanisms by which transcription and mRNA processing occur. These extracts are able to recapitulate accurate transcription initiation and splicing in vitro, which has been useful in direct functional studies. They also serve as the starting material for purification of proteins that can then be reassembled in functional studies or examined in more detail biochemically. This unit describes the preparation of nuclear extracts from cultured cells and optimized production of transcriptionally active extracts from HeLa cells. Additional protocols describe optimization of the method to increase the yield of specific proteins, adaptation of the method for downstream applications such as affinity purification, and preparation of the cytoplasmic (S-100) fraction.
Fair Algorithms for Learning in Allocation Problems

Settings such as lending and policing can be modeled by a centralized agent allocating a scarce resource (e.g. loans or police officers) amongst several groups, in order to maximize some objective (e.g. loans given that are repaid, or criminals that are apprehended). Often in such problems fairness is also a concern. One natural notion of fairness, based on general principles of equality of opportunity, asks that conditional on an individual being a candidate for the resource in question, the probability of actually receiving it is approximately independent of the individual's group. For example, in lending this would mean that equally creditworthy individuals in different racial groups have roughly equal chances of receiving a loan. In policing it would mean that two individuals committing the same crime in different districts would have roughly equal chances of being arrested. In this paper, we formalize this general notion of fairness for allocation problems and investigate its algorithmic consequences. Our main technical results include an efficient learning algorithm that converges to an optimal fair allocation even when the allocator does not know the frequency of candidates (i.e. creditworthy individuals or criminals) in each group. This algorithm operates in a censored feedback model in which only the number of candidates who received the resource in a given allocation can be observed, rather than the true number of candidates in each group. This models the fact that we do not learn the creditworthiness of individuals we do not give loans to and do not learn about crimes committed if the police presence in a district is low. As an application of our framework and algorithm, we consider the predictive policing problem, in which the resource being allocated to each group is the number of police officers assigned to each district. The learning algorithm is trained on arrest data gathered from its own deployments on previous days, resulting in a potential feedback loop that our algorithm provably overcomes. In this case, the fairness constraint asks that the probability that an individual who has committed a crime is arrested should be independent of the district in which they live. We investigate the performance of our learning algorithm on the Philadelphia Crime Incidents dataset.
Flexible Sensitivity Analysis for Observational Studies Without Observable Implications

A fundamental challenge in observational causal inference is that assumptions about unconfoundedness are not testable from data. Assessing sensitivity to such assumptions is therefore important in ...
Children’s reasoning about decimals and its relation to fraction learning and mathematics achievement.

Reasoning about numerical magnitudes is a key aspect of mathematics learning. Most research examining the relation of magnitude understanding to general mathematics achievement has focused on whole number and fraction magnitudes. The present longitudinal study (N = 435) used a 3-step latent class analysis to examine reasoning about magnitudes on a decimal comparison task in 4th grade, before systematic decimals instruction. Three classes of response patterns were identified, indicating empirically distinct levels of decimal magnitude understanding. Class 1 students consistently gave correct responses, suggesting that they understood decimal properties even before systematic decimal instruction. Class 2 students were accurate when a 0 immediately followed the decimal, but were inaccurate when a zero was added to the end of the decimal string, suggesting a partial understanding of place value; their performance was also negatively influenced by a whole number bias. Class 3 students showed misunderstanding of both place value and a whole number bias. Class membership accurately predicted 6th grade mathematics achievement, after controlling for whole number and fraction magnitude understanding as well as demographic and cognitive factors. Taken together, the findings suggest students may benefit from instruction that emphasizes decimal properties earlier in school. (PsycINFO Database Record (c) 2019 APA, all rights reserved)