cssi/SciSciGPT-SciSciNet huggingface dataset:
Feedback-induced bistability of an optically levitated nanoparticle: A Fokker-Planck treatment

Optically levitated nanoparticles have recently emerged as versatile platforms for investigating macroscopic quantum mechanics and enabling ultrasensitive metrology. In this paper we theoretically consider two damping regimes of an optically levitated nanoparticle cooled by cavityless parametric feedback. Our treatment is based on a generalized Fokker-Planck equation derived from the quantum master equation presented recently and shown to agree very well with experiment [B. Rodenburg, L. P. Neukirch, A. N. Vamivakas, and M. Bhattacharya, Quantum model of cooling and force sensing with an optically trapped nanoparticle, Optica 3, 318 (2016)]. For low damping, we find that the resulting Wigner function yields the single-peaked oscillator position distribution and recovers the appropriate energy distribution derived earlier using a classical theory and verified experimentally [J. Gieseler, R. Quidant, C. Dellago, and L. Novotny, Dynamic relaxation of a levitated nanoparticle from a non-equilibrium steady state, Nat. Nano. 9, 358 (2014)]. For high damping, in contrast, we predict a double-peaked position distribution, which we trace to an underlying bistability induced by feedback. Unlike in cavity-based optomechanics, stochastic processes play a major role in determining the bistable behavior. To support our conclusions, we present analytical expressions as well as numerical simulations using the truncated Wigner function approach. Our work opens up the prospect of developing bistability-based devices, characterization of phase-space dynamics, and investigation of the quantum-classical transition using levitated nanoparticles.
The orbit and size of (87) Sylvia's Romulus from the 2015 apparition

Abstract Using the US Air Force’s Starfire Optical Range 3.5 meter telescope with adaptive optics and a laser guidestar, we obtained 68 images of asteroid (87) Sylvia and its satellite Romulus over 6 nights in March and May of 2015. Adding an additional 3 images from earlier observations on one night in November 2012, we are able to derive a circular (but not an eccentric) orbit for Romulus, leading to a density for Sylvia of 1.37 ± 0.04 gm/cm3. Extending the time base to 14 years by combining our data with previous observations from Keck, HST, and the VLT reported in the literature, we can fit for a new circular orbit and change the density estimate slightly to 1.35 ± 0.04 gm/cm3. By fitting a ratio of two Fourier series to the measured magnitude difference between Sylvia (V=12.5) and Romulus, which ranged from 4.1 to 5.0 in the J-band ( λ = 1.2 μ m), and modeling both as triaxial ellipsoids, we are able to derive prolate spheroid equatorial diameters for Romulus of 41(±27) × 30(±16) km. This assumes that Romulus is rotating synchronously with its 3.64 d orbital period. However, decomposing the differential lightcurve between Sylvia and Romulus reveals a much shorter 7.96 hr rotational period, leading to more elongated prolate spheroid diameters of 82(±7) × 21(±2) km. As far as we know, our 3.5 m telescope is the smallest ground-based telescope to ever image any asteroid’s moon.
The Economics of Innovation and Technical Change in Agriculture

Abstract Innovation in agriculture differs from innovation elsewhere in the economy in several important ways. In this chapter we highlight differences arising from (a) the atomistic nature of agricultural production, (b) the spatial specificity of agricultural technologies and the implications for spatial spillovers and the demand for adaptive research, and (c) the role of coevolving pests and diseases and changing weather and climate giving rise to demands for maintenance research, and other innovations that reduce the susceptibility of agricultural production to these uncontrolled factors. These features of agriculture mean that the nature and extent of market failures in the provision of agricultural research and innovation differ from their counterparts in other parts of the economy. Consequently, different government policies are implied, including different types of intellectual property protection and different roles of the government in funding and performing research. Informal innovation and technical discovery processes characterized agriculture from its beginnings some 10,000 years ago, providing a foundation for the organized science and innovation activities that have become increasingly important over the past century or two. This chapter reviews innovation and technical change in agriculture in this more-recent period, paying attention to research institutions, investments, and intellectual property. Special attention is given to issues of R&D attribution, the nature and length of the lags between research spending and its impacts on productivity, and various dimensions of innovation outcomes, including rates of return to agricultural research and the distribution of benefits.
Effect of Parent Training on Adaptive Behavior in Children With Autism Spectrum Disorder and Disruptive Behavior: Results of a Randomized Trial.

Objective This study examined the impact of parent training on adaptive behavior in children with autism spectrum disorder (ASD) and disruptive behavior. Methods This was a 24-week, 6-site, randomized trial of parent training versus parent education in 180 children with ASD (aged 3−7 years; 158 boys and 22 girls) and moderate or greater behavioral problems. Parent training included specific strategies to manage disruptive behavior over 11 to 13 sessions, 2 telephone boosters, and 2 home visits. Parent education provided useful information about autism but no behavior management strategies over 12 core sessions and 1 home visit. In a previous report, we showed that parent training was superior to parent education in reducing disruptive behavior in young children with ASD. Here, we test whether parent training is superior to parent education in improving daily living skills as measured by the parent-rated Vineland Adaptive Behavior Scales II. The long-term impact of parent training on adaptive functioning is also presented. Results At week 24, the parent training group showed a 5.7-point improvement from baseline on the Daily Living domain compared to no change in parent education ( p = .004; effect size = 0.36). On the Socialization domain, there was a 5.9-point improvement in parent training versus a 3.1-point improvement in parent education ( p = .11; effect size = 0.29). Gains in the Communication domain were similar across treatment groups. The gain in Daily Living was greater in children with IQ of >70. However, the interaction of treatment-by-IQ was not significant. Gains in Daily Living at week 24 were maintained upon re-evaluation at 24 weeks posttreatment. Conclusion These results support the model that reduction in disruptive behavior can lead to improvement in activities of daily living. By contrast, the expected trajectory for adaptive behavior in children with ASD is often flat and predictably declines in children with intellectual disability. In the parent training group, higher-functioning children achieved significant gains in daily living skills. Children with intellectual disability kept pace with time. Clinical trial registration information —Randomized Trial of Parent Training for Young Children With Autism (RUBI); http://clinicaltrials.gov/; NCT01233414.
WEAR IN TOTAL HIP ARTHROPLASTY USING CERAMIC HEAD: 10 YEARS MAXIMUM FU

Introduction The number of total hip arthroplasties in young patients is continuosly increasing. Nowdays, the study of the materials wear, with the goal of improving the survivorship of implants, represents a fundamental subject in this kind of surgery. The role of ceramic materials in the valutation of types of wear is particularly known. Materials and Methods We have selected 834 patients, underwent total hip arthroplasty, in which a ceramic head was impalnted with a maximum follow up of ten years. 367 patients were males and 467 were females, operated by 14 surgeons of the same equipe of Orthopaedic and Traumatology Department. A postero-lateral approach, according to Gibson Moore, and an extrarotator tendons transosseal repair was performed. Results 446 ceramic liners, 354 polyethylene liners and 34 metallic liners were used. 18 types of stems, 5 of which stemless, were implanted. The mean survivorship of all cohrt of patients was 92% at 10 years. No ceramic heads and liners breakage occurred. In particular, of 69 total hip arthroplasties, implanted in 2005, only 3 were revised. Discussion In our cohort review no major failures of ceramic components were observed. These datas suggested the importance of design and up grading of new materials, in order to achieve better long term results. Therefore, the ceramic components represent the gold standard, specifically in young active patients with good long term results reguarding functional outcomes and wear of implants. Conclusions The use of ceramic head, assembled with ceramic or polyethylene liners, also demonstrated good results at 10 years follow up. Ceramic-on- polyethylene is a valid alternative to ceramic-on-ceramic in consideration of the lower cost and theoretical lower risk of breakage.
Clinical features of young women with hypergonadotropic amenorrhea

One hundred fifteen women under age 40 presenting with hypergonadotropic amenorrhea (follicle-stimulating hormone greater than 40 mIU/mL) were evaluated. Incomplete pubertal maturation and chromosomal abnormalities were more likely in the 18 women (15.7%) with primary amenorrhea than in those with secondary amenorrhea. The 97 women with secondary hypergonadotropic amenorrhea were significantly more apt to complain of symptoms of estrogen deficiency, have been pregnant before diagnosis, and have evidence of ovulation after diagnosis. Withdrawal bleeding occurred commonly (greater than 48%) in those women administered exogenous progestin. Immune abnormalities occurred with approximately equal frequency (17.4%), and spinal bone density was decreased in both groups.
User Profile Visualization to facilitate MSLIM-model-based Social Influence Analysis based on Slow Intelligence Approach.

Identifying the hub nodes (the most influential users) in an information diffusion network is a central research topic in social influence analysis. In [2], we developed the Multi-task Sparse Linear Influence Model (MSLIM) to automatically select topic-sensitive influential nodes in an implicit network. Our method firstly needs to determine the active node set to model the global volume of the contagions of the entire network nodes. The active node set is chosen by a simple rule in [2]. However, different set leads to different model performance. Reference [4] proposed a new framework called Slow Intelligence System, which can continuously learn, search the appropriate method and propagate information according to the environment to improve the performance over time. In this paper, we develop a slow intelligence based active user definition system by utilizing user profile visualization to help interactively determine active node sets in MSLIM model. We apply our system on a set of 2.6 million tweets of 1000 users on twitter. We show that our system can efficiently utilize user's profile visualization techniques to facilitate determining the appropriate active node sets.
Triclosan Exposure Is Associated with Rapid Restructuring of the Microbiome in Adult Zebrafish

Growing evidence indicates that disrupting the microbial community that comprises the intestinal tract, known as the gut microbiome, can contribute to the development or severity of disease. As a result, it is important to discern the agents responsible for microbiome disruption. While animals are frequently exposed to a diverse array of environmental chemicals, little is known about their effects on gut microbiome stability and structure. Here, we demonstrate how zebrafish can be used to glean insight into the effects of environmental chemical exposure on the structure and ecological dynamics of the gut microbiome. Specifically, we exposed forty-five adult zebrafish to triclosan-laden food for four or seven days or a control diet, and analyzed their microbial communities using 16S rRNA amplicon sequencing. Triclosan exposure was associated with rapid shifts in microbiome structure and diversity. We find evidence that several operational taxonomic units (OTUs) associated with the family Enterobacteriaceae appear to be susceptible to triclosan exposure, while OTUs associated with the genus Pseudomonas appeared to be more resilient and resistant to exposure. We also found that triclosan exposure is associated with topological alterations to microbial interaction networks and results in an overall increase in the number of negative interactions per microbe in these networks. Together these data indicate that triclosan exposure results in altered composition and ecological dynamics of microbial communities in the gut. Our work demonstrates that because zebrafish afford rapid and inexpensive interrogation of a large number of individuals, it is a useful experimental system for the discovery of the gut microbiome’s interaction with environmental chemicals.
An Umpolung Approach for the Chemoselective Arylation of Selenocysteine in Unprotected Peptides

Herein we report an umpolung strategy for the bioconjugation of selenocysteine in unprotected peptides. This mild and operationally simple approach takes advantage of the electrophilic character of an oxidized selenocysteine (Se–S bond) to react with a nucleophilic arylboronic acid to provide the arylated selenocysteine within hours. This reaction is amenable to a wide range of boronic acids with different biorelevant functional groups and is unique to selenocysteine. Experimental evidence indicates that under oxidative conditions the arylated derivatives are more stable than the corresponding alkylated selenocysteine.
Comparison of efficacy of pharmacological treatments for chronic idiopathic constipation: a systematic review and network meta-analysis

Objective To compare efficacy of pharmacotherapies for chronic idiopathic constipation (CIC) based on comparisons to placebo using Bayesian network meta-analysis. Data sources We conducted searches (inception to May 2015) of MEDLINE, EMBASE, Scopus and Cochrane Central, as well as original data from authors or drug companies for the medications used for CIC. Study selection Phase IIB and phase III randomised, placebo-controlled trials (RCT) of ≥4 weeks9 treatment for CIC in adults with Rome II or III criteria for functional constipation; trials included at least one of four end points. Data extraction and synthesis Two investigators independently evaluated all full-text articles that met inclusion criteria and extracted data for primary and secondary end points, risk of bias and quality of evidence. Outcomes Primary end points were ≥3 complete spontaneous bowel movements (CSBM)/week and increase over baseline by ≥1 CSBM/week. Secondary end points were change from baseline (Δ b ) in the number of SBM/week and Δ b CSBM/week. Results Twenty-one RCTs (9189 patients) met inclusion and end point criteria: 9 prucalopride, 3 lubiprostone, 3 linaclotide, 2 tegaserod, 1 each velusetrag, elobixibat, bisacodyl and sodium picosulphate (NaP). All prespecified end points were unavailable in four polyethylene glycol studies. Bisacodyl, NaP, prucalopride and velusetrag were superior to placebo for the ≥3 CSBM/week end point. No drug was superior at improving the primary end points on network meta-analysis. Bisacodyl appeared superior to the other drugs for the secondary end point, Δ b in number of SBM/week. Conclusions Current drugs for CIC show similar efficacy. Bisacodyl may be superior to prescription medications for Δ b in the number of SBM/week in CIC.
Bayesian inference of recursive sequences of group activities from tracks

We present a probabilistic generative model for inferring a description of coordinated, recursively structured group activities at multiple levels of temporal granularity based on observations of individuals' trajectories. The model accommodates: (1) hierarchically structured groups, (2) activities that are temporally and compositionally recursive, (3) component roles assigning different subactivity dynamics to subgroups of participants, and (4) a nonparametric Gaussian Process model of trajectories. We present an MCMC sampling framework for performing joint inference over recursive activity descriptions and assignment of trajectories to groups, integrating out continuous parameters. We demonstrate the model's expressive power in several simulated and complex real-world scenarios from the VIRAT and UCLA Aerial Event video data sets.
Nephrologists Versus Peripherally Inserted Central Catheters: Are the PICCs Winning?

Because of their low rate of procedure-related complications, ease of placement, and favorable cost profile, peripherally inserted central venous catheters (PICCs) have increased in prevalence ([1][1]–[3][2]). In patients with difficult to obtain intravenous access, PICCs are a reasonable form of
Maximizing CNN Accelerator Efficiency Through Resource Partitioning

Convolutional neural networks (CNNs) are revolutionizing machine learning, but they present significant computational challenges. Recently, many FPGA-based accelerators have been proposed to improve the performance and efficiency of CNNs. Current approaches construct a single processor that computes the CNN layers one at a time; the processor is optimized to maximize the throughput at which the collection of layers is computed. However, this approach leads to inefficient designs because the same processor structure is used to compute CNN layers of radically varying dimensions.We present a new CNN accelerator paradigm and an accompanying automated design methodology that partitions the available FPGA resources into multiple processors, each of which is tailored for a different subset of the CNN convolutional layers. Using the same FPGA resources as a single large processor, multiple smaller specialized processors increase computational efficiency and lead to a higher overall throughput. Our design methodology achieves 3.8x higher throughput than the state-of-the-art approach on evaluating the popular AlexNet CNN on a Xilinx Virtex-7 FPGA. For the more recent SqueezeNet and GoogLeNet, the speedups are 2.2x and 2.0x.
THE CAUSES OF TKA FAILURE: AVOIDING YOUR NEXT REVISION

Most presentations about total knee arthroplasty begin with a statement that the procedure has been one of the great successes of modern surgery. However, not all patients consider their total knee a success. Success requires that patients experience relief of arthritic pain, return of function, and express satisfaction with the result. Patients need to be aware of the limitations of implants and accept reasonable expectations for the arthroplasty. If they don9t, your next revision will likely be on a unsatisfied patient who had unrealistic expectations. The surgeon who operated on the patient for the primary intervention may feel obliged to try to make it better. Don9t make that mistake. Avoid your next revision by only intervening when there is a clear indication. In a recent patient survey, 15–20% of patients (and maybe more) were not completely satisfied with their arthroplasty in spite of having recent implant designs. It is a fact that some patients will not be satisfied with any intervention. Fibromyalgia, depression, high narcotic use for arthritic pain, secondary gain (e.g., Worker9s Compensation claims pending) are some of the conditions that predict a difficult post-operative course and an unsatisfied patient who will push for revision. T o avoid your next revision, choose patients wisely and make sure they understand that the total joint is a poor substitute for the normal knee. Design surgeons and engineers have developed techniques for a specific implant system to minimise the problems of malrotation, malalignment, instability, anterior knee pain, stiffness, loosening and polyethylene wear. Surgeons should be careful to use the recommended implantation philosophy and technique to avoid these problems. Choose implant systems with a proven track record. Learn how and why to use the instruments correctly. Study a system well and know the nuances. If you don9t know the system well enough, take a course from the designers and ask questions. Avoid your next revision by using a prosthesis system as it was intended. Prosthetic joint infection remains a major reason for revision. Some patients have a greater chance of developing infection. Attention to detail from pre-operative preparation to rehabilitation will minimise, but cannot eliminate, the occurrence of infection. The recently published International Consensus on Prosthetic Joint Infection contains recommendations that should be followed to minimise the chance of infection. Avoid your next revision by following the recommendations to minimise the chance of infection. The indication for revision is diagnosis of a problem that can be corrected with surgery. If a patient is satisfied with a result, revision surgery would only rarely be indicated regardless of the radiographic result. (Severe wear would be an exception to this.) Avoid you next revision by recognizing that “the enemy of good is better”.
ABROA: Audio-based room-occupancy analysis using Gaussian mixtures and Hidden Markov models

This paper outlines preliminary steps towards the development of an audio-based room-occupancy analysis model. Our approach borrows from speech recognition tradition and is based on Gaussian Mixtures and Hidden Markov Models. We analyse possible challenges encountered in the development of such a model, and offer several solutions including feature design and prediction strategies. We provide results obtained from experiments with audio data from a retail store in Palo Alto, California. Model assessment is done via leave-two-out Bootstrap and model convergence achieves good accuracy, thus representing a contribution to multimodal people counting algorithms.
Three's Compromised Too: Circular Insecurity for Any Cycle Length from Ring-LWE

A public-key encryption scheme is k-circular secure if a cycle ofi¾?k encrypted secret keys $$\mathsf {Enc} _{pk_{1}}sk_{2}, \mathsf {Enc} _{pk_{2}}sk_{3}, \ldots , \mathsf {Enc} _{pk_{k}}sk_{1}$$ is indistinguishable from encryptions of zeros. Circular security has applications in a wide variety of settings, ranging from security of symbolic protocols to fully homomorphic encryption. A fundamental question is whether standard security notions like IND-CPA/CCA imply k-circular security. For the case $$k=2$$, several works over the past years have constructed counterexamples--i.e., schemes that are CPA or even CCA secure but not 2-circular secure--under a variety of well-studied assumptions SXDH, decision linear, and LWE. However, for $$k > 2$$ the only known counterexamples are based on strong general-purpose obfuscation assumptions. In this work we construct k-circular security counterexamples for any $$k \ge 2$$ based on ring-LWE. Specifically:for any constant $$k=O1$$, we construct a counterexample based on n-dimensional plain LWE for $$\mathrm{poly}n$$ approximation factors;for any $$k=\mathrm{poly}\lambda $$, we construct one based on degree-n ring-LWE for at most subexponential $$\exp n^{\varepsilon }$$ factors. Moreover, both schemes are $$k'$$-circular insecure for $$2 \le k' \le k$$. Notably, our ring-LWE construction does not immediately translate to an LWE-based one, because matrix multiplication is not commutative. To overcome this, we introduce a new "tensored" variant of LWE which provides the desired commutativity, and which we prove is actually equivalent to plain LWE.
Pay for Talk: How the Use of Shareholder-Value Language Affects CEO Compensation

The language that signals conformity to a prevailing norm can contribute to the appearance of managerial competency and organizational legitimacy. We argue that top corporate managers’ use of language that is congruent with a prevailing norm leads the boards of directors to evaluate the managers more favourably and to grant a higher level of compensation. We test this argument by analysing the letters to shareholders from 334 US firms and examine the CEOs’ expression of the shareholder value principle, which is a prevailing model of corporate governance in the USA. We found that the use of shareholder-value language is significantly related to a higher level of CEO compensation and that the effect of shareholder-value language is greater when shareholder activism is stronger.
Triton Hopper: Exploring Neptune’s Captured Kuiper Belt Object

Neptune’s moon Triton is a fascinating object, a dynamic moon with an atmosphere, and geysers. Given the availability of volatiles (primarily nitrogen ice) on the surface a concept study was performed to see how these ices could be used as propellant to hop across the surface and explore the many different terrains of the moon. Termed Triton Hopper, the Phase 1 mission concept study was funded by the NASA Innovative Advanced Concepts (NIAC) program in 2015.
Charter Schools and Labor Market Outcomes

We estimate the impact of charter schools on early-life labor market outcomes in Texas. We find that, at the mean, charter schools have no impact on test scores and a negative impact on earnings. N...
CERAMENT BONE VOID FILLER WITH GENTAMICIN INCREASES BONE FORMATION AND DECREASES DETECTABLE INFECTION IN A RAT MODEL OF DEBRIDED OSTEOMYELITIS

To test the hypothesis that: CERAMENT[™]|G (C-G) would improve new bone growth and decrease infection rate after debridement as compared with 1) CERAMENT|BONE VOID FILLER (CBVF) and 2) no void filler in a rat osteomyelitis model. 72 Sprague Dawley rats were injected with 1.5 × 10∧6 CFU of S. aureus into a drill hole in the right tibia. After 3 weeks, the osteomyelitic defect was debrided, and filled with either: 1) C-G (n=32), 2) CBVF (n=20), or 3) nothing (n=20). 6 weeks after the second surgery, 20 rats from each group were sacrificed and the right tibias were harvested. A long-term group (n=12) of C-G treated rats were also sacrificed at 6 months after the second surgery. The tissues were sonicated and the colony forming units in the sonicate were quantified by serial dilutions and culture. MicroCT was used to quantify the new bone growth (BV/TV) in the debrided osteomyelitic void. Histological samples were analyzed for the presence of a neutrophil response by a blinded pathologist. (*: p Positive cultures in: ○ 30% of animals treated with CBVF ○ 25% of animals treated with no void filler ○ 0% of animals treated with C-G (*) Neutrophil reaction in: ○ 35% of animals treated with CBVF ○ 50% of animals treated with no void filler ○ 0% of animals treated with C-G (*) The BV/TV in: ○ C-G treated rats was 24% greater than CBVF treated rats (*) ○ C-G treated rats was 94% greater than rats treated with no void filler (*) ○ CBVF treated rats was 56% greater than rats treated with no void filler (*) Animals sacrificed at 6 months which were treated with C-G did not have any evidence of infection by culture or histology. The bone mass of the implanted limb was higher than the contralateral (non-operated) side. CERAMENT|G decreased the rate of infection and increased new bone growth as compared with both CBVF and no void filler in a debrided osteomyelitic environment. Animals treated with C-G at 6 months showed no evidence of infection and retained a higher bone mass relative to the contralateral (non-operated) side. This study supports the use of CERAMENT|G as a readily available void filler which could be used in osteomyelitic environments after debridement.
ACETABULAR FRACTURES: THE ROLE OF ARTHROPLASTY

ORIF is the treatment of choice for the majority of acetabular fractures with the ultimate goal of native hip preservation. As long as anatomic reduction and joint congruency is achieved, the results of ORIF have led to good to excellent outcomes. Total hip arthroplasty (THA) after acetabular fracture is indicated: 1.) acutely in the setting of a fracture where ORIF has been shown to portray a poor prognosis (severe femoral head and/or posterior wall impaction, dome comminution (gull sign) or 2.) in the presence of the sequelae of acetabular fractures such as posttraumatic arthritis or osteonecrosis. Independent of the setting, THA after acetabular fracture presents unique challenges to the orthopaedic surgeon and in many instances requires a team approach that includes both joint reconstruction and trauma specialists. The main goal of the operation is to restore continuity of the fractured columns prior to implantation of an uncemented acetabular component. Technical challenges include infection, residual pelvic deformity, acetabular bone loss and/ or ununited fractures, osteonecrosis of bone fragments, retained hardware, heterotopic ossification, sciatic nerve compromise, and the difficulties in obtaining long-term socket fixation. Careful pre-operative assessment with review of x-rays and CT scans to assess bone loss, fracture nonunion, and infection is necessary. The surgeon must anticipate more blood loss, longer operative times, and difficulties with exposure and must anticipate the need of special tools intra-operatively such as pelvic reconstruction plates, use of autogenous bone graft, metal cutting instruments and post-operative heterotopic ossification prophylaxis either in the form of NSAIDS or radiation. In case of a necrosis, nonunion, or bone loss principles of revision total hip arthroplasty are commonly used and today the use of highly porous metals is particularly useful. Cemented acetabular components should be avoided. Care should be taken with cup position as distorted anatomy may influence cup position and bony impingement may lead to dislocation. The results of THA in general has provided excellent pain relief and functional improvement but the biggest historical problem has been socket fixation and bearing surface wear, hopefully now improved with the advent of highly porous metals and alternative bearing surfaces.
A Hybrid Causal Search Algorithm for Latent Variable Models

Existing score-based causal model search algorithms such as GES (and a speeded up version, FGS) are asymptotically correct, fast, and reliable, but make the unrealistic assumption that the true causal graph does not contain any unmeasured confounders. There are several constraint-based causal search algorithms (e.g RFCI, FCI, or FCI+) that are asymptotically correct without assuming that there are no unmeasured confounders, but often perform poorly on small samples. We describe a combined score and constraint-based algorithm, GFCI, that we prove is asymptotically correct. On synthetic data, GFCI is only slightly slower than RFCI but more accurate than FCI, RFCI and FCI+.
Topological Data Analysis

Topological data analysis (TDA) can broadly be described as a collection of data analysis methods that find structure in data. These methods include clustering, manifold estimation, nonlinear dimension reduction, mode estimation, ridge estimation and persistent homology. This paper reviews some of these methods.
The asymptotic form of non-global logarithms, black disc saturation, and gluonic deserts

We develop an asymptotic perturbation theory for the large logarithmic behavior of the non-linear integro-differential equation describing the soft correlations of QCD jet measurements, the Banfi-Marchesini-Smye (BMS) equation. This equation captures the late-time evolution of radiating color dipoles after a hard collision. This allows us to prove that at large values of the control variable (the non-global logarithm, a function of the infra-red energy scales associated with distinct hard jets in an event), the distribution has a gaussian tail. We compute the decay width analytically, giving a closed form expression, and find it to be jet geometry independent, up to the number of legs of the dipole in the active jet. Enabling the asymptotic expansion is the correct perturbative seed, where we perturb around an anzats encoding formally no real emissions, an intuition motivated by the buffer region found in jet dynamics. This must be supplemented with the correct application of the BFKL approximation to the BMS equation in collinear limits. Comparing to the asymptotics of the conformally related evolution equation encountered in small-x physics, the Balitisky-Kovchegov (BK) equation, we find that the asymptotic form of the non-global logarithms directly maps to the black-disc unitarity limit of the BK equation, despite the contrasting physical pictures. Indeed, we recover the equations of saturation physics in the final state dynamics of QCD.
Boundary-Layer Stability Analysis for Stetson’s Mach 6 Blunt-Cone Experiments

The results of a seminal experimental study of the effects of bluntness and swallowing length on transition on an 8 deg cone at zero angle of attack in Mach 6 high-Reynolds-number flow are analyzed with the STABL-2D computational fluid dynamics code package. Mean flow solutions and parabolized stability analyses for a total of 11 different nose-tip bluntnesses, ranging from sharp to a 15.24 mm radius, are obtained. For the sharpest cases, the N factor at transition is approximately seven; but, as bluntness increases and the calculated swallowing distance lengthens, the computed N factor at the experimentally observed transition location drops below the level at which Mack’s second mode would be expected to lead to transition. These results indicate that the dominant instability mechanism for the bluntest cases is not the second mode, and oblique mode analysis also excludes these modes as the dominant instability mechanism.
The Effect of Category Spanning on the Lethality and Longevity of Terrorist Organizations

This paper examines the effect of category spanning on the lethality and survival of terrorist organizations. The core argument is that terrorist organizations that span multiple and distant ideological categories will be less lethal and end more quickly than other terrorist organizations whose membership lies squarely within a single ideological category. Using information on 385 terrorist organizations, this paper finds support for these claims, controlling for Islamic ideological orientation, suicide tactics, and measures of organizational capacity. In addition, de novo terrorist organizations are more likely than spin-off organizations to end by becoming part of the political process.
Evaluating the evaluation of cancer driver genes

Sequencing has identified millions of somatic mutations in human cancers, but distinguishing cancer driver genes remains a major challenge. Numerous methods have been developed to identify driver genes, but evaluation of the performance of these methods is hindered by the lack of a gold standard, that is, bona fide driver gene mutations. Here, we establish an evaluation framework that can be applied to driver gene prediction methods. We used this framework to compare the performance of eight such methods. One of these methods, described here, incorporated a machine-learning–based ratiometric approach. We show that the driver genes predicted by each of the eight methods vary widely. Moreover, the P values reported by several of the methods were inconsistent with the uniform values expected, thus calling into question the assumptions that were used to generate them. Finally, we evaluated the potential effects of unexplained variability in mutation rates on false-positive driver gene predictions. Our analysis points to the strengths and weaknesses of each of the currently available methods and offers guidance for improving them in the future.
Characterization of electric solid propellant pulsed microthrusters

Electric solid propellants are an attractive option for propulsion because they are ignited only by an applied electric current. This leads to capabilities such as on-demand throttling and reigniti...
Application of Taxonomic Modeling to Microbiota Data Mining for Detection of Helminth Infection in Global Populations

Human microbiome data from genomic sequencing technologies is fast accumulating, giving us insights into bacterial taxa that contribute to health and disease. The predictive modeling of such microbiota count data for the classification of human infection from parasitic worms, such as helminths, can help in the detection and management across global populations. Real-world datasets of microbiome experiments are typically sparse, containing hundreds of measurements for bacterial species, of which only a few are detected in the bio-specimens that are analyzed. This feature of microbiome data produces the challenge of needing more observations for accurate predictive modeling and has been dealt with previously, using different methods of feature reduction. To our knowledge, integrative methods, such as transfer learning, have not yet been explored in the microbiome domain as a way to deal with data sparsity by incorporating knowledge of different but related datasets. One way of incorporating this knowledge is by using a meaningful mapping among features of these datasets. In this paper, we claim that this mapping would exist among members of each individual cluster, grouped based on phylogenetic dependency among taxa and their association to the phenotype. We validate our claim by showing that models incorporating associations in such a grouped feature space result in no performance deterioration for the given classification task. In this paper, we test our hypothesis by using classification models that detect helminth infection in microbiota of human fecal samples obtained from Indonesia and Liberia countries. In our experiments, we first learn binary classifiers for helminth infection detection by using Naive Bayes, Support Vector Machines, Multilayer Perceptrons, and Random Forest methods. In the next step, we add taxonomic modeling by using the SMART-scan module to group the data, and learn classifiers using the same four methods, to test the validity of the achieved groupings. We observed a 6% to 23% and 7% to 26% performance improvement based on the Area Under the receiver operating characteristic (ROC) Curve (AUC) and Balanced Accuracy (Bacc) measures, respectively, over 10 runs of 10-fold cross-validation. These results show that using phylogenetic dependency for grouping our microbiota data actually results in a noticeable improvement in classification performance for helminth infection detection. These promising results from this feasibility study demonstrate that methods such as SMART-scan can be utilized in the future for knowledge transfer from different but related microbiome datasets by phylogenetically-related functional mapping, to enable novel integrative biomarker discovery.
On the Orbital Inclination of Proxima Centauri b

The field of exoplanetary science has seen discovery rates increase dramatically over recent years, due largely to the data from the Kepler mission. Even so, individual discoveries of planets orbiting nearby stars are very important for studies of characterization and near-term follow-up prospects. The recent discovery of a terrestrial planet candidate orbiting Proxima Centauri presents numerous opportunities for studying a super-Earth within our own stellar backyard. One of the remaining ambiguities of the discovery is the true mass of the planet since the discovery signature was obtained via radial velocities. Here, we describe the effect of orbital inclination on the Proxima Centauri planet, in terms of mass, radius, atmosphere, and albedo. We calculate the astrometric, angular separation, and reflected light properties of the planet including the effects of orbital eccentricity. We further provide dynamical simulations that show how the presence of additional terrestrial planets within the Habitable Zone varies as a function of inclination. Finally, we discuss these effects in the context of future space-based photometry and imaging missions that could potentially detect the planetary signature and resolve the inclination and mass ambiguity of the planet.
Thermal contact resistance of cured gel polymeric thermal interface material

This paper reports the experimental results on the contact resistance of curable polymer gel thermal interface materials (TIMs) that have different mechanical properties due to difference in the rheology of the polymers. A semi-analytical model for the prediction of the thermal contact resistance of cured gel TIMs is also introduced in this paper. A novel method of finding the transition from grease type behavior to gel type behavior, which is very important for post reliability stress performance, based on G' (storage shear modulus) and G'' (loss shear modulus) measurements is reported. Further, post thermal cycling thermal resistance degradation rate of gel TIMs are related to the ratio of G and G''. Finally, design guidelines for gel TIMs for use in flip-chip packages comprising heat spreaders are proposed.
Flywheel technology development program for aerospace applications

An overview of advanced flywheel development for energy storage in aerospace applications is presented. The advantages offered by this emerging technology are described and the current NASA approach toward developing the technology is presented.
Finite Temperature String Method with Umbrella Sampling: Application on a Side Chain Flipping in Mhp1 Transporter.

Protein conformational change is of central importance in molecular biology. Here we demonstrate a computational approach to characterize the transition between two metastable conformations in all-atom simulations. Our approach is based on the finite temperature string method, and the implementation is essentially a generalization of umbrella sampling simulations with Hamiltonian replica exchange. We represent the transition pathway by a curve in the conformational space, with the curve parameter taken as the reaction coordinate. Our approach can efficiently refine a transition pathway and compute a one-dimensional free energy as a function of the reaction coordinate. A diffusion model can then be used to calculate the forward and backward transition rates, the major kinetic quantities for the transition. We applied the approach on a local transition in the ligand-free Mhp1 transporter, between its outward-facing conformation and an intermediate conformation with the side chain of Phe305 flipped to the ou...
Restriction of the Fourier Transform to Some Oscillating Curves

Let $$\phi $$ be a smooth function on a compact interval I. Let $$\begin{aligned} \gamma (t)=\left( t,t^2,\ldots ,t^{n-1},\phi (t)\right) . \end{aligned}$$ In this paper, we show that $$\begin{aligned} \left( \int _I \big |\hat{f}(\gamma (t))\big |^q \big |\phi ^{(n)}(t)\big |^{\frac{2}{n(n+1)}} \mathrm{{d}}t\right) ^{1/q}\le C\Vert f\Vert _{L^p(\mathbb R^n)} \end{aligned}$$ holds in the range $$\begin{aligned} 1\le p<\frac{n^2+n+2}{n^2+n},\quad 1\le q<\frac{2}{n^2+n}p'. \end{aligned}$$ This generalizes an affine restriction theorem of Sjolin (Stud Math 51:169–182, 1974) for $$n=2$$ . Our proof relies on ideas of Sjolin (Stud Math 51:169–182, 1974) and Drury (Ann Inst Fourier (Grenoble) 35(1):117–123, 1985), and more recently Bak, Oberlin and Seeger (J Aust Math Soc 85(1):1–28, 2008) and Stovall (Am J Math 138(2):449–471, 2016), as well as a variation bound for smooth functions.
On estimating maximum matching size in graph streams

We study the problem of estimating the maximum matching size in graphs whose edges are revealed in a streaming manner. We consider both insertion-only streams, which only contain edge insertions, and dynamic streams that allow both insertions and deletions of the edges, and present new upper and lower bound results for both cases.On the upper bound front, we show that an α-approximate estimate of the matching size can be computed in dynamic streams using O(n2/α4) space, and in insertion-only streams using O(n/α2)-space. These bounds respectively shave off a factor of α from the space necessary to compute an α-approximate matching (as opposed to only size), thus proving a non-trivial separation between approximate estimation and approximate computation of matchings in data streams.On the lower bound front, we prove that any α-approximation algorithm for estimating matching size in dynamic graph streams requires [EQUATION] bits of space, even if the underlying graph is both sparse and has arboricity bounded by O(α). We further improve our lower bound to Ω(n/α2) in the case of dense graphs. These results establish the first non-trivial streaming lower bounds for super-constant approximation of matching size.Furthermore, we present the first super-linear space lower bound for computing a (1 + e)-approximation of matching size even in insertion-only streams. In particular, we prove that a (1 + e)-approximation to matching size requires RS(n) · n1−O(e) space; here, RS(n) denotes the maximum number of edge-disjoint induced matchings of size Θ(n) in an n-vertex graph. It is a major open problem with far-reaching implications to determine the value of RS(n), and current results leave open the possibility that RS(n) may be as large as n/log n. Moreover, using the best known lower bounds for RS(n), our result already rules out any O(n · poly(log n/e))-space algorithm for (1 + e)-approximation of matchings. We also show how to avoid the dependency on the parameter RS(n) in proving lower bound for dynamic streams and present a near-optimal lower bound of n2−O(e) for (1 + e)-approximation in this model.Using a well-known connection between matching size and matrix rank, all our lower bounds also hold for the problem of estimating matrix rank. In particular our results imply a near-optimal n2−O(e) bit lower bound for (1 + e)-approximation of matrix ranks for dense matrices in dynamic streams, answering an open question of Li and Woodruff (STOC 2016).
Convective Merging of Vortex Cores in Lift-Generated Wakes

The several wake vortices that originate from aircraft wingtips, flap edges, engine pylons, etc. usually merge, in the far field to form a single pair, whose structure determines the hazard posed to encountering aircraft. In order to gain an understanding of the process whereby vortices merge and disperse, a numercial study was made of the interaciton of two-dimension al, time-dependent, inviscid vortical regions. It was found that discrete boundaries, which depend on the structure and spacing of the vortices, distinguish merging from nonmerging situations. Furthermore, certain arrays of finite vortex cores that alternate in sign were found to undergo division and merging that may be useful in alleviating the hazard posed by aircraft wakes. AR b CL Ce Ct c c de d/
Tracking the Untrackable: Learning to Track Multiple Cues with Long-Term Dependencies

The majority of existing solutions to the Multi-Target Tracking (MTT) problem do not combine cues over a long period of time in a coherent fashion. In this paper, we present an online method that encodes long-term temporal dependencies across multiple cues. One key challenge of tracking methods is to accurately track occluded targets or those which share similar appearance properties with surrounding objects. To address this challenge, we present a structure of Recurrent Neural Networks (RNN) that jointly reasons on multiple cues over a temporal window. Our method allows to correct data association errors and recover observations from occluded states. We demonstrate the robustness of our data-driven approach by tracking multiple targets using their appearance, motion, and even interactions. Our method outperforms previous works on multiple publicly available datasets including the challenging MOT benchmark.
The many guises of a neutral fermion singlet

The addition of a neutral fermion singlet to the Standard Model (SM) of particle interactions leads to many diverse possibilities. It is not necessarily a right-handed neutrino. I discuss many of the simplest and most interesting scenarios of possible new physics with this approach. In particular, I propose the possible spontaneous breaking of baryon number, resulting in the massless “sakharon”.