bluuebunny/crossref_metadata_2025 huggingface dataset:
Prolonged length of stay in the emergency department and increased risk of hospital mortality in patients with sepsis requiring ICU admission
Authors: Zhang Zhongheng , Bokhari Faran , Guo Yizhan , Goyal Hemant
Published: December 2018

Background and objectives

Delayed patient admission to the intensive care unit (ICU) from the ED is common in China. Patients with severe sepsis or septic shock requiring ICU admission are in need of specialised monitoring and tailored treatment. Delayed admission to the ICU might be associated with adverse clinical outcomes for patients with sepsis.

Methods

Patients with sepsis admitted to the ICU from the ED from January 2010 to April 2018 were retrospectively identified from a clinical data warehouse. The primary endpoint was in-hospital mortality. Length of stay in ED (EDLOS) was compared between survivors and non-survivors. A multivariable regression model was employed to adjust for potential confounding due to patient clinical condition.

Results

A total of 1997 patients, including 473 non-survivors and 1524 survivors, were included. The crude mortality rate for patients with EDLOS <6 hours was 21.4%, which was significantly lower than patients with EDLOS of 12–24 hours (31.9%), and those with EDLOS >24 hours (31.8%). After adjusting for PaO2/FiO2, serum creatinine, age, Sequential Organ Failure Assessment, body mass index, lactate, comorbidities and infection site, EDLOS continued to be independently associated with increased risk of hospital mortality. Compared with the group with EDLOS <6 hours, those with EDLOS between 12and24 hours (OR 1.82, 95% CI 1.28 to 2.58) and EDLOS >24 hours (OR 1.79, 95% CI 1.27 to 2.52) showed a significantly increased risk of death.

Conclusions

Our study shows that prolonged EDLOS is independently associated with increased risk of hospital mortality in patients with sepsis requiring ICU admission.
Gender differences in cardiovascular risk assessment in elderly adults in Ecuador: Evidence from a national survey
Authors: Sisa Ivan
Published: December 2018

The present study aimed to predict the risk of developing cardiovascular disease (CVD) over a 5-year period and how it might vary by sex in an ethnically diverse population of older adults. We used a novel CVD risk model built and validated in older adults named the Systematic Coronary Risk Evaluation in Older Persons (SCORE OP). A population-based study analyzed a total of 1307 older adults. Analyses were done by various risk categories and sex. Of the study population, 54% were female with a mean age of 75±7.1 years. According to the SCORE OP model, individuals were classified as having low (9.8%), moderate (48.1%), and high or very high risk (42.1%) of CVD-related mortality. Individuals at higher risk of CVD were more likely to be male compared with females, 53.9% vs 31.8%, respectively (p<0.01). Males were more likely to be younger, living in rural areas, had higher levels of schooling, and with the exception of smoking status and serum triglycerides, had lower values of traditional risk factors than females. In addition, males were less likely to require blood pressure-lowering therapy and statin drugs than females. This gender inequality could be driven by sociocultural determinants and a risk factor paradox in which lower levels of the cardiovascular risk factors are associated with an increase rather than a reduction in mortality. These data can be used to tailor primary prevention strategies such as lifestyle counseling and therapeutic measures in order to improve male elderly health, especially in low-resource settings.
CAP2 mutation leads to impaired actin dynamics and associates with supraventricular tachycardia and dilated cardiomyopathy
Authors: Aspit Liam , Levitas Aviva , Etzion Sharon , Krymko Hanna , Slanovic Leonel , Zarivach Raz , Etzion Yoram , Parvari Ruti
Published: December 2018

Background

Dilated cardiomyopathy (DCM) is a primary myocardial disease leading to contractile dysfunction, progressive heart failure and excessive risk of sudden cardiac death. Around half of DCM cases are idiopathic, and genetic factors seem to play an important role.

Aim

We investigated a possible genetic cause of DCM in two consanguineous children from a Bedouin family.

Methods and results

Using exome sequencing and searching for rare homozygous variations, we identified a nucleotide change in the donor splice consensus sequence of exon 7 inCAP2as the causative mutation. Using patient-derived fibroblasts, we demonstrated that the mutation causes skipping of exons 6 and 7. The resulting protein is missing 64 amino acids in its N-CAP domain that should prevent its correct folding.CAP2protein level was markedly reduced without notable compensation by the homolog CAP1. However, β-actin mRNA was elevated as demonstrated by real-time qPCR. In agreement with the essential role of CAP2 in actin filament polymerization, we demonstrate that the mutation affects the kinetics of repolymerization of actin in patient fibroblasts.

Conclusions

This is the first report of a recessive deleterious mutation in CAP2 and its association with DCM in humans. The clinical phenotype recapitulates the damaging effects on the heart observed inCap2knockout mice including DCM and cardiac conduction disease, but not the other effects on growth, viability, wound healing and eye development. Our data underscore the importance of the proper kinetics of actin polymerization for normal function of the human heart.
The Speech Arm Vision Eyes (SAVE) scale predicts large vessel occlusion stroke as well as more complicated scales
Authors: Keenan Kevin J , Smith Wade S
Published: December 2018

Introduction

The Speech Arm Vision Eyes (SAVE) scale, a 4-item clinical scale emphasizing binary scoring and avoidance of nuanced examination distinctions, predicts LVOs with similar characteristics as more complex scales.

Methods

Receiver operating characteristic analyses of the prospective STOPStroke study assessed the ability of the SAVE scale and other published scales to predict LVO. We identified scale thresholds with positive likelihood ratios with 95% confidence intervals of ≥5.0 or negative likelihood ratios with 95% confidence intervals of ≤0.5.

Results

735patients were studied. LVO prevalence was 33%. Area under the curve was 0.79 for SAVE, 0.82 for FAST-ED, 0.80 for mNIHSS and NIHSS, and lower for all other scales. SAVE=4, EMSA=6, mNIHSS≥10, NIHSS≥16, and RACE≥8 had positive likelihood ratios with 95% confidence intervals ≥5.0. SAVE≥2, CPSS≥2, C-STAT≥1, EMSA≥4, FAST-ED≥3, G-FAST≥3, mNIHSS≥6, NIHSS≥9, PASS≥1, RACE≥2, VAN=1, and 3I-SS≥1 had negative likelihood ratios with 95% confidence intervals ≤0.5.

Conclusions

SAVE=4 performed similarly to more complex scales at predicting LVO. Other simplified scales did not have thresholds with positive likelihood ratios with 95% confidence intervals ≥5.0. Validation is need in a prehospital cohort of patients with suspected stroke.
Use of geosocial networking applications is independently associated with diagnosis of STI among men who have sex with men testing for STIs: findings from the cross-sectional MSM Internet Survey Ireland (MISI) 2015
Authors: O’Connor Lois , O'Donnell Kate , Barrett Peter , Hickson Ford Colin Ian , McCartney Daniel , Quinlan Mick , Barrasa Alicia , Fitzgerald Margaret , Igoe Derval
Published: December 2018

Objectives

MSM Internet Survey Ireland (MISI) 2015 was an anonymous, self-completed, cross-sectional internet survey assessing sexual behaviours and health needs among men who have sex with men (MSM) in Ireland. We explored factors associated with self-reported STI diagnosis among MSM who were sexually active and had an STI test in the previous year.

Methods

We compared the study population (n=1158; 37% of total population), with the sexually active MISI population not testing for STIs (n=1620; 52% of total population). Within the study population, we identified sociodemographics and sexual behaviours associated with self-reporting STI diagnosis. We used multivariable logistic regression to estimate adjusted odds ratios (aORs).

Results

The sociodemographics, lifestyle and sexual behaviours of the study population differed significantly from the sexually active MISI population who did not test for STIs. Within the study population, 65% met a sexual partner via geosocial networking smartphone application (GSNa) and 21% self-reported an STI diagnosis in the previous year. On univariable analysis, factors associated with STI diagnosis included: older age, identifying as gay, HIV-positive status, increasing number of sexual partners in the previous year, condomless anal intercourse (CAI) with ≥2 non-steady partners and using GSNa to meet a new sexual partner in the previous year or most recent sexual partner. On multivariable analysis, STI diagnosis was associated with: being aged 25–39 years (aOR 1.8, 95% CI 1.04 to 3.15), CAI with ≥2 non-steady partners (aOR 2.8, 95% CI 1.84 to 4.34), total number of sexual partners (aOR 1.02, 95% CI 1.00 to 1.03) and using GSNa to meet a new sexual partner (aOR 1.95, 95% CI 1.12 to 3.39).

Conclusions

STI diagnosis among MSM testing for STIs is associated with GSNa use, as well as sexual behaviours. GSNas are key settings for STI prevention interventions, which should prioritise men with high numbers of sexual partners and those with multiple CAI partners.
Results from a cross-sectional sexual and reproductive health study among school girls in Tanzania: high prevalence of bacterial vaginosis
Authors: Francis Suzanna C , Holm Hansen Christian , Irani Julia , Andreasen Aura , Baisley Kathy , Jespers Vicky , Crucitti Tania , Changalucha John , Hayes Richard J , Nnko Soori , Watson-Jones Deborah , Buvé Anne
Published: December 2018

Objectives

Bacterial vaginosis (BV) increases women’s susceptibility to sexually transmitted infections (STIs) and HIV and may partly explain the high incidence of STI/HIV among girls and young women in East and southern Africa. The objectives of this study were to investigate the association between BV and sexual debut, to investigate other potential risk factors of BV and to estimate associations between BV and STIs.

Methods

Secondary school girls in Mwanza, aged 17 and 18 years, were invited to join a cross-sectional study. Consenting participants were interviewed and samples were obtained for STI and BV testing. Factors associated with prevalent BV were analysed using multivariable logistic regression. Y-chromosome was tested as a biomarker for unprotected penile-vaginal sex.

Results

Of the 386 girls who were enrolled, 163 (42%) reported having ever had penile-vaginal sex. Ninety-five (25%) girls had BV. The prevalence of BV was 33% and 19% among girls who reported or did not report having ever had penile-vaginal sex, respectively. BV was weakly associated with having ever had one sex partner (adjusted odds ratio (aOR) 1.59;95% CI 0.93 to 2.71) and strongly associated with two or more partners (aOR = 3.67; 95% CI 1.75 to 7.72), receptive oral sex (aOR 6.38; 95% CI 1.22 to 33.4) and having prevalent human papillomavirus infection (aOR = 1.73; 95% CI 1.02 to 2.95). Of the 223 girls who reported no penile-vaginal sex, 12 (5%) tested positive for an STI and 7 (3%) tested positive for Y-chromosome. Reclassifying these positive participants as having ever had sex did not change the key results.

Conclusions

Tanzanian girls attending school had a high prevalence of BV. Increasing number of sex partner was associated with BV; however, 19% of girls who reported no penile-vaginal sex had BV. This suggests that penile-vaginal sexual exposure may not be a prerequisite for BV. There was evidence of under-reporting of sexual debut.
Maternal history of miscarriages and measures of fertility in relation to childhood asthma
Authors: Magnus Maria Christine , Karlstad Øystein , Parr Christine Louise , Page Christian M , Nafstad Per , Magnus Per , London Stephanie J , Wilcox Allen J , Nystad Wenche , Håberg Siri Eldevik
Published: December 2018

Background

It remains unclear what underlies the greater risk of asthma reported among children conceived by assisted reproductive technologies (ART).

Objective

Our aim was to clarify the role of parental subfertility and unmeasured confounding on the association between ART and childhood asthma, and to examine the possibility for common mechanisms underlying parental subfertility and miscarriages influencing asthma pathogenesis.

Methods

We used data from national Norwegian health registries (n=474 402) and the Norwegian Mother and Child Cohort Study (MoBa) (n=75 797). We used log-linear regression to estimate overall associations, and fixed-effects logistic regression to estimate associations within siblings.

Results

ART offspring had greater asthma risk, the adjusted relative risk (aRR) was 1.20 (95% CI 1.09 to 1.32) in the registry-based cohort, and 1.42 (95% CI 1.14 to 1.76) in MoBa. The sibling analysis yielded similar associations, although the CI included the null value. The elevated asthma risk among ART offspring was attenuated when they were compared with spontaneously conceived offspring with time to conception >12 months, aRR 1.22 (95% CI 0.95 to 1.57). Asthma risk also increased with maternal history of early miscarriages (≤12 weeks), with an aRR of 1.07 (95% CI 1.03 to 1.11) for one, aRR 1.18 (95% CI 1.10 to 1.26) for two and aRR 1.24 (95% CI 1.12 to 1.37) for three or more.

Conclusion

Our findings indicate that both parental subfertility and characteristics related to the ART procedure itself might increase offspring asthma risk, although this needs to be confirmed in future studies, and further suggest that common mechanisms underlying parental subfertility and recurrent miscarriages might influence offspring asthma pathogenesis.
Involvement of local Indigenous peoples in Arctic research — expectations, needs and challenges perceived by early career researchers
Authors: Sjöberg Ylva , Gomach Sarah , Kwiatkowski Evan , Mansoz Mathilde
Published: December 2018

Rapid changes in the natural and social environments of the Arctic region have led to increased scientific presence across the Arctic. Simultaneously, the importance of involving local Indigenous peoples in research activities is increasingly recognized for several reasons, including knowledge sharing and sustainable development. This study explores Arctic early career researchers’ (ECRs) perceptions on involving local Indigenous peoples in their research. The results, based on 108 online survey respondents from 22 countries, show that ECRs value the knowledge of local Indigenous peoples and generally wish to extend the involvement of this group in their research. ECRs in North America and in the social sciences have more experience working with Indigenous communities and value it more than researchers in the Nordic area and in the natural sciences. Respondents cited more funding, networking opportunities, and time as the main needs for increasing collaborations. The results of this study are helpful for developing strategies to build good relationships between scientists and Indigenous peoples and for increasing the involvement of Arctic Indigenous peoples in science and engagement of their knowledge systems. The complementary views from Arctic Indigenous peoples are, however, needed for a full understanding of how to effectively achieve this.
Determination of optimal sowing dates and densities of winter wheat under Quebec growing conditions
Authors: Allard Francis , Vanasse Anne , Pageau Denis , Tremblay Gilles , Durand Julie , Vachon Elizabeth
Published: December 2018

The objective of this project was to determine the optimal sowing dates and densities for winter wheat to increase winter survival and yield under Quebec growing conditions. The trials were carried out from 2014 to 2016 at four sites, representing three cereal production zones (zones 1, 2, and 3). Three cultivars were assessed using four sowing dates and four seeding densities (250, 350, 450, and 550 seeds m−2). In the first year, the wheat at two of the four sites survived (82%–100%), and in the second year, all the sites showed good survival rates (69%–99%). In zone 2, winter survival was higher for the early sowing dates compared with later dates. Sowing date and seeding density had no effect on survival in zones 1 and 3. Maximum yields were attained with sowing dates from mid- to late September in zone 1; from early to mid-September in zone 2; and from mid-August to mid-September in zone 3. An increase in seeding density from 250 to 550 seeds m−2led to an average yield gain of 9% in zones 2 and 3, but no gain in zone 1. Winter survival rates and yield differ between cultivars.
THE VARIATOR WITH LEVER MECHANISMS
Authors: Abdiraimov Abdusamad
Published: December 2018

This article describes the device and the principle of the variator with lever mechanisms intended for the contact ratio to change within a wide range and making it capable of reversibility. Structural analysis is carried out and the main relationship between the lengths of the links, the equation for the determination of the contact ratio and variants of structural schemes of variator with lever mechanisms are shown.
THE EXPERIMENTAL RESEARCH ON AXIS ORBIT OF MIXED-FLOW PUMP
Authors: Qian Li , Wei Li , Leilei Ji , Weidong Shi , Xiaofan Zhao , Xiaoping Jiang
Published: December 2018

In order to study the vibration state of the rotor shaft in mixed-flow pump under stable operation, the axis orbit measurement was carried out under design flow condition. The results show that there are some jagged high harmonic signals and the original axis orbit has an "8" shaped distribution, which can be caused by factors like the shafting friction and misalignment. Most part of vibration energy is in 1X frequency, indicating that the shafting unbalance is caused by hydraulic excitation and other related factors. In the meantime, the axis orbit shape of 2X frequency indicates that the rotor misalignment also has an influence on the running stability. This study aims at providing practical guidance and instruction for improving the mixed-flow pump stability and preventing the deterioration of vibration fault.
COMPARATIVE SURVEY OF VARIOUS STATIC AND DYNAMIC MODELS OF PNEUMATIC ARTIFICIAL MUSCLES
Authors: Sárosi József , Piteľ Ján , Tóthová Mária , Hošovský Alexander , Bíró István
Published: December 2018

A lesser known type of pneumatic actuators is pneumatic artificial muscle (PAM) although these pneumatic actuators play an important role in industrial, medical and other applications. In this study a PAM model based on the assumption Euler’s law is developed, some static force models (geometric model-based static force model, static force model using maximum force of PAM and static force model using a polynomial function) are compared to Sárosi’s force model and two dynamic models based on Sárosi’s static force model and Hill’s muscle model are presented.
DURABILITY TESTS: statistical analysIs for variable amplitude loads
Authors: Jimenez Moises
Published: December 2018

The reduced time available for product evolution has forced original equipment manufacturers and their suppliers to develop new components and subsystems more rapidly, while taking into consideration the reliability of the final product in terms of its durability. Although durability is nowadays improved through virtual testing, it is mandatory to perform experimental tests for the final release of a product. The complexity of this kind of testing has increased. In the early 20th century, evaluations began to represent a real life time history with standardized load–time histories. This coincided with the introduction of the closed-loop test system to reproduce more realistic time histories. Most tier-1 suppliers perform such testing at their own development centers or at consultant test facilities; however, design engineers and product management need to understand the requirements of the testing and be able to interpret the results to understand how to improve a mechanical component. Most papers published on durability give experimental results for constant-amplitude loads and analytical predictions. However, information on tests with time histories and statistical analysis is very often missing. The present paper reviews the main aspects of durability tests for variable-amplitude loads, including the main statistical analysis conducted to reproduce damage to vehicles traveling on roads and proving grounds in the laboratory.
SOGRO — Terrestrial full-tensor detector for mid-frequency gravitational waves
Authors: Paik Ho Jung , Vol Moody M. , Norton Ronald S.
Published: December 2018

Laser interferometer gravitational-wave (GW) detectors are observing signals from merging black hole and neutron star binaries with a frequency window from 10[Formula: see text]Hz to several kHz. Future space-based laser interferometers will open a new window of 0.1[Formula: see text]mHz to 0.1[Formula: see text]Hz. In this paper, we discuss the possibility of constructing a terrestrial GW detector named Superconducting Omni-directional Gravitational Radiation Observatory (SOGRO), which can fill the missing frequency window, 0.1 to 10[Formula: see text]Hz, with astronomically interesting sensitivity. SOGRO measures all five tensor components of the spacetime metric, which results in uniform sensitivity for all-sky directions and enables identification of the source direction and wave polarization with a single detector. Seismic and Newtonian gravity noise pose the greatest challenges for constructing ground-based detectors below 10[Formula: see text]Hz. SOGRO utilizes enhanced mechanical and electrical stabilities of materials at cryogenic temperatures to reject common-mode seismic noise to a very high degree. Further, its full-tensor characteristic gives an advantage in the rejection of the Newtonian noise over conventional detectors.
ANNEALING BEHAVIOR OF Ni-TiO2NANOCOMPOSITES
Authors: NIU TE , CHEN WEIWEI , CHEN HUANWU , WANG LU
Published: December 2018

Ni-TiO2nanocomposite have been prepared by electrodeposition. The microstructure and tribological behavior of Ni-TiO2nanocomposite before and after annealing have been investigated compared with as-deposited Ni-TiO2composite. The results demonstrated that TiO2nanoparticles usually collected along the grain boundaries and nickel grains changed from columnar grains into equiaxed grains after annealing. HRTEM photographs indicated that the diffusion between crystalline nickel and TiO2nanoparticles did happen after annealing. Wear results indicated that the main wear mechanism of as-deposited Ni-TiO2nanocomposite was adhesion wear. The wear resistance of Ni-TiO2nanocomposite heat-treated is better than as-deposited Ni-TiO2nanocomposite because the oxidation layers on the worn surface of Ni-TiO2nanocomposite masked the strengthening effect of small grain size. The corrosion behavior also has been studied and it is found that annealing reduces the corrosion resistance of composite coatings.
EFFECT OF DIFFUSION PROCESS ON COATING IN HOT-DIPPED ALUMINIZED STEEL
Authors: DING YUWEN , CHEN XIAOCHUN , LIU YA , SU XUPING
Published: December 2018

Aluminized steels possess excellent corrosion resistance due to the formation of Al-Fe solution phases and intermetallic compounds in coatings. Ni was added to baths to further improve the corrosion resistance of the coatings at high temperature. Here, the role of Ni in the formation of coatings and the effect of diffusion process on the developing of coatings were investigated. 45 steels were immersed in Al-Ni baths (Al-1mass% Ni, Al-3mass% Ni, and Al-5mass% Ni) and diffusion-treated at 1023 and 1123[Formula: see text]K for 20, 40 and 100[Formula: see text]min, respectively. The coatings of samples were analyzed via scanning electron microscopy (SEM) along with energy-dispersive X-ray spectroscopy (EDS). X-ray diffraction (XRD) was further used to confirm the types of phases that formed during diffusion treatment. The formations of intermetallic coating layers were also analyzed via the diffusion path. More continuous Al3Ni layer and compact coating were obtained with diffusion treatment at 1023[Formula: see text]K for 40[Formula: see text]min.
MATHEMATICAL PROPERTIES OF AMERICAN CHOOSER OPTIONS
Authors: QIU SHI , MITRA SOVAN
Published: December 2018

The American chooser option is a relatively new compound option that has the characteristic of offering exceptional risk reduction for highly volatile assets. This has become particularly significant since the start of the global financial crisis. In this paper, we derive mathematical properties of American chooser options. We show that the two optimal stopping boundaries for American chooser options with finite horizon can be characterized as the unique solution pair to a system formed by two nonlinear integral equations, arising from the early exercise premium (EEP) representation. The proof of EEP representation is based on the method of change-of-variable formula with local time on curves. The key mathematical properties of American chooser options are proved, specifically smooth-fit, continuity of value function and continuity of free-boundary among others. We compare the performance of the American chooser option against the American strangle option. We also conduct numerical experiments to illustrate our results.
EQUILIBRIUM ASSET RETURNS IN FINANCIAL MARKETS
Authors: MADAN DILIP B. , SCHOUTENS WIM
Published: December 2018

Return distributions in the class of pure jump limit laws are observed to reflect numerous asymmetries between the upward and downward motions of asset prices. The return distributions are modeled by self-decomposable parametric laws with all parameters continuously responding to each other. Fixed points of the response functions define equilibrium distributions. The equilibrium distributions that can arise in practice are constrained by the level of return acceptability they may attain. As a consequence, expected returns are equated to risk measured by the cost of purchasing the negative of the centered return. The asymmetries studied include differences in scale, speed, power variation, excitation and cross-excitation.
Energy Harvesting Optimizing with a Magnetostrictive Cantilever Beam System
Authors: Borowiec Marek , Syta Arkadiusz , Litak Grzegorz
Published: December 2018

Vibration energy is scavenged by a beam system based on magnetostrictive material (MsM). The system consists of interconnected substructural beams (aluminum and magnetostrictive layers) with a neutral stress axis shifted away from the axis of symmetry of the magnetostrictive beam. The coil that generates the electromotive force is wound on the composite beam. The study investigates the effects of a tip mass placed at the end of the beam and the beam thickness influence. Multiple solutions are found for high amplitudes, and the optimal configuration of the operating conditions is proposed. In addition, the sensitivity of the system to the initial conditions is compared for the first three resonance areas, leading to determination of two types of solutions with different levels of power output.
Laplacian-based 3D mesh simplification with feature preservation
Authors: Lyu Wei , Wu Wei , Zhang Lin , Wu Zhaohui , Zhou Zhong
Published: December 2018

We propose a novel Laplacian-based algorithm that simplifies triangle surface meshes and can provide different preservation ratios of geometric features. Our efficient and fast algorithm uses a 3D mesh model as input and initially detects geometric features by using a Laplacian-based shape descriptor (L-descriptor). The algorithm further performs an optimized clustering approach that combines a Laplacian operator with K-means clustering algorithm to perform vertex classification. Moreover, we introduce a Laplacian weighted cost function based on L-descriptor to perform feature weighting and error statistics comparison, which are further used to change the deletion order of the model elements and preserve the saliency features. Our algorithm can provide different preservation ratios of geometric features and may be extended to handle arbitrary mesh topologies. Our experiments on a variety of 3D surface meshes demonstrate the advantages of our algorithm in terms of improving accuracy and applicability, and preserving saliency geometric features.
Democratizing Authority in the Built Environment
Authors: Andersen Michael P. , Kolb John , Chen Kaifei , Fierro Gabe , Culler David E. , Katz Randy
Published: December 2018

Operating systems and applications in the built environment have relied upon central authorization and management mechanisms that restrict their scalability, especially with respect to administrative overhead. We propose a new set of primitives encompassing syndication, security, and service execution that unifies the management of applications and services across the built environment, while enabling participants to individually delegate privilege across multiple administrative domains with no loss of security or manageability. We show how to leverage a decentralized authorization syndication platform to extend the design of building operating systems beyond the single administrative domain of a building. The authorization system leveraged is based on blockchain smart contracts to permit decentralized and democratized delegation of authorization without central trust. Upon this, a publish/subscribe syndication tier and a containerized service execution environment are constructed. Combined, these mechanisms solve problems of delegation, federation, device protection and service execution that arise throughout the built environment. We leverage a high-fidelity city-scale emulation to verify the scalability of the authorization tier, and briefly describe a prototypical democratized operating system for the built environment using this foundation.

This is an extension of work presented in Ref. [3].
Pivot Tracing
Authors: Mace Jonathan , Roelke Ryan , Fonseca Rodrigo
Published: December 2018

Monitoring and troubleshooting distributed systems is notoriously difficult; potential problems are complex, varied, and unpredictable. The monitoring and diagnosis tools commonly used today—logs, counters, and metrics—have two important limitations: what gets recorded is defined
a priori
, and the information is recorded in a component- or machine-centric way, making it extremely hard to correlate events that cross these boundaries. This article presents Pivot Tracing, a monitoring framework for distributed systems that addresses both limitations by combining dynamic instrumentation with a novel relational operator: the happened-before join. Pivot Tracing gives users, at runtime, the ability to define arbitrary metrics at one point of the system, while being able to select, filter, and group by events meaningful at other parts of the system, even when crossing component or machine boundaries. We have implemented a prototype of Pivot Tracing for Java-based systems and evaluate it on a heterogeneous Hadoop cluster comprising HDFS, HBase, MapReduce, and YARN. We show that Pivot Tracing can effectively identify a diverse range of root causes such as software bugs, misconfiguration, and limping hardware. We show that Pivot Tracing is dynamic, extensible, and enables cross-tier analysis between inter-operating applications, with low execution overhead.
Mechanisms and Policies for Controlling Distributed Solar Capacity
Authors: Bashir Noman , Irwin David , Shenoy Prashant , Taneja Jay
Published: December 2018

The rapid expansion of intermittent grid-tied solar capacity is making the job of balancing electricity’s real-time supply and demand increasingly challenging. Recent work proposes mechanisms for actively controlling solar power in the grid at individual sites by enabling software to cap it as a fraction of its time-varying maximum output. However, while enforcing an equal fraction of each solar site’s time-varying maximum output results in “fair” short-term contributions of solar power across all sites, it does not result in “fair” long-term contributions of solar energy. Enforcing fair long-term energy access is important when controlling distributed solar capacity, since limits on solar output impact the compensation users receive for net metering and the battery capacity required to store excess solar energy. This discrepancy arises from fundamental differences in enforcing “fair” access to the grid to contribute solar energy, compared to analogous fair sharing in networks and processors. To address the problem, we first present both a centralized and distributed algorithm to enable control of distributed solar capacity that enforces fair grid energy access. We then present multiple policies that show how utilities can leverage this new distributed rate-limiting mechanism to reduce variations in grid demand from intermittent solar generation.
A Systematic Review for Smart City Data Analytics
Authors: Moustaka Vaia , Vakali Athena , Anthopoulos Leonidas G.
Published: December 2018

Smart cities (SCs) are becoming highly sophisticated ecosystems at which innovative solutions and smart services are being deployed. These ecosystems consider SCs as data production and sharing engines, setting new challenges for building effective SC architectures and novel services. The aim of this article is to “connect the pieces” among Data Science and SC domains, with a systematic literature review which identifies the core topics, services, and methods applied in SC data monitoring. The survey focuses on data harvesting and data mining processes over repeated SC data cycles. A survey protocol is followed to reach both quantitative and semantically important entities. The review results generate useful taxonomies for data scientists in the SC context, which offers clear guidelines for corresponding future works. In particular, a taxonomy is proposed for each of the main SC data entities, namely, the “D Taxonomy” for the data production, the “M Taxonomy” for data analytics methods, and the “S Taxonomy” for smart services. Each of these taxonomies clearly places entities in a classification which is beneficial for multiple stakeholders and for multiple domains in urban smartness targeting. Such indicative scenarios are outlined and conclusions are quite promising for systemizing.
Modeling User Intrinsic Characteristic on Social Media for Identity Linkage
Authors: Yu Xianqi , Sun Yuqing , Bertino Elisa , Li Xin
Published: December 2018

Most users on social media have intrinsic characteristics, such as interests and political views, that can be exploited to identify and track them, thus raising privacy and identity concerns in online communities. In this article, we investigate the problem of user identity linkage on two behavior datasets collected from different experiments. Specifically, we focus on user linkage based on users’ interaction behaviors with respect to content topics. We propose an embedding method to model a topic as a vector in a latent space to interpret its deep semantics. Then a user is modeled as a vector based on his or her interactions with topics. The embedding representations of topics are learned by optimizing the joint-objective: the compatibility between topics with similar semantics, the discriminative abilities of topics to distinguish identities, and the consistency of the same user’s characteristics from two datasets. The effectiveness of our method is verified on real-life datasets and the results show that it outperforms related methods. We also analyze failure cases in the application of our identity linkage method. Our analysis shows that factors such as the visibility and variance of user behaviors and users’ group psychology can result in mis-linkages. We also analyze the details of the behaviors of some representative users to understand the essential reasons for their identity being mis-linked. We find that these users have high variance level in their behaviors. According to the above experimental results, we introduce a confidence score into identity linkage to provide information about the accuracy of the method results.
Filtering Translation Bandwidth with Virtual Caching
Authors: Yoon Hongil , Lowe-Power Jason , Sohi Gurindar S.
Published: December 2018

Heterogeneous computing with GPUs integrated on the same chip as CPUs is ubiquitous, and to increase programmability many of these systems support virtual address accesses from GPU hardware. However, this entails address translation on every memory access. We observe that future GPUs and workloads show very high bandwidth demands (up to 4 accesses per cycle in some cases) for shared address translation hardware due to frequent private TLB misses. This greatly impacts performance (32% average performance degradation relative to an ideal MMU). To mitigate this overhead, we propose a software-agnostic, practical, GPU virtual cache hierarchy. We use the virtual cache hierarchy as an effective address translation bandwidth filter. We observe many requests that miss in private TLBs find corresponding valid data in the GPU cache hierarchy. With a GPU virtual cache hierarchy, these TLB misses can be filtered (i.e., virtual cache hits), significantly reducing bandwidth demands for the shared address translation hardware. In addition, accelerator-specific attributes (e.g., less likelihood of synonyms) of GPUs reduce the design complexity of virtual caches, making a whole virtual cache hierarchy (including a shared L2 cache) practical for GPUs. Our evaluation shows that the entire GPU virtual cache hierarchy effectively filters the high address translation bandwidth, achieving almost the same performance as an ideal MMU. We also evaluate L1-only virtual cache designs and show that using a whole virtual cache hierarchy obtains additional performance benefits (1.31× speedup on average).
The semantics of transactions and weak memory in x86, Power, ARM, and C++
Authors: Chong Nathan , Sorensen Tyler , Wickerson John
Published: December 2018

Weak memory models provide a complex, system-centric semantics for concurrent programs, while transactional memory (TM) provides a simpler, programmer-centric semantics. Both have been studied in detail, but their
combined
semantics is not well understood. This is problematic because such widely-used architectures and languages as x86, Power, and C++ all support TM, and all have weak memory models.

Our work aims to clarify the interplay between weak memory and TM by extending existing axiomatic weak memory models (x86, Power, ARMv8, and C++) with new rules for TM. Our formal models are backed by automated tooling that enables (1) the synthesis of tests for validating our models against existing implementations and (2) the model-checking of TM-related transformations, such as lock elision and compiling C++ transactions to hardware. A key finding is that a proposed TM extension to ARMv8 currently being considered within ARM Research is incompatible with lock elision without sacrificing portability or performance.
Write-rationing garbage collection for hybrid memories
Authors: Akram Shoaib , Sartor Jennifer B. , McKinley Kathryn S. , Eeckhout Lieven
Published: December 2018

Emerging Non-Volatile Memory (NVM) technologies offer high capacity and energy efficiency compared to DRAM, but suffer from limited write endurance and longer latencies. Prior work seeks the best of both technologies by combining DRAM and NVM in hybrid memories to attain low latency, high capacity, energy efficiency, and durability. Coarsegrained hardware and OS optimizations then spread writes out (wear-leveling) and place highly mutated pages in DRAM to extend NVM lifetimes. Unfortunately even with these coarse-grained methods, popular Java applications exact impractical NVM lifetimes of 4 years or less. This paper shows how to make hybrid memories practical, without changing the programming model, by enhancing garbage collection in managed language runtimes. We find object write behaviors offer two opportunities: (1) 70% of writes occur to newly allocated objects, and (2) 2% of objects capture 81% of writes to mature objects. We introduce writerationing garbage collectors that exploit these fine-grained behaviors. They extend NVM lifetimes by placing highly mutated objects in DRAM and read-mostly objects in NVM. We implement two such systems. (1) Kingsguard-nursery places new allocation in DRAM and survivors in NVM, reducing NVM writes by 5× versus NVM only with wear-leveling. (2) Kingsguard-writers (KG-W) places nursery objects in DRAM and survivors in a DRAM observer space. It monitors all mature object writes and moves unwritten mature objects from DRAM to NVM. Because most mature objects are unwritten, KG-W exploits NVM capacity while increasing NVM lifetimes by 11×. It reduces the energy-delay product by 32% over DRAM-only and 29% over NVM-only. This work opens up new avenues for making hybrid memories practical.
Accelerating search-based program synthesis using learned probabilistic models
Authors: Lee Woosuk , Heo Kihong , Alur Rajeev , Naik Mayur
Published: December 2018

A key challenge in program synthesis concerns how to efficiently search for the desired program in the space of possible programs. We propose a general approach to accelerate search-based program synthesis by biasing the search towards likely programs. Our approach targets a standard formulation, syntax-guided synthesis (SyGuS), by extending the grammar of possible programs with a probabilistic model dictating the likelihood of each program. We develop a weighted search algorithm to efficiently enumerate programs in order of their likelihood. We also propose a method based on transfer learning that enables to effectively learn a powerful model, called probabilistic higher-order grammar, from known solutions in a domain. We have implemented our approach in a tool called Euphony and evaluate it on SyGuS benchmark problems from a variety of domains. We show that Euphony can learn good models using easily obtainable solutions, and achieves significant performance gains over existing general-purpose as well as domain-specific synthesizers.
Modularity for decidability of deductive verification with applications to distributed systems
Authors: Taube Marcelo , Losa Giuliano , McMillan Kenneth L. , Padon Oded , Sagiv Mooly , Shoham Sharon , Wilcox James R. , Woos Doug
Published: December 2018

Proof automation can substantially increase productivity in formal verification of complex systems. However, unpredictablility of automated provers in handling quantified formulas presents a major hurdle to usability of these tools. We propose to solve this problem not by improving the provers, but by using a modular proof methodology that allows us to produce
decidable
verification conditions. Decidability greatly improves predictability of proof automation, resulting in a more practical verification approach. We apply this methodology to develop verified implementations of distributed protocols, demonstrating its effectiveness.
Klotho deficiency aggravates sepsis-related multiple organ dysfunction
Authors: Jorge Lectícia B. , Coelho Fernanda O. , Sanches Talita R. , Malheiros Denise M. A. C. , Ezaquiel de Souza Leandro , dos Santos Fernando , de Sá Lima Larissa , Scavone Cristóforo , Irigoyen Maria , Kuro-o Makoto , Andrade Lucia
Published: December 2018

Sepsis-induced organ failure is characterized by a massive inflammatory response and oxidative stress. Acute kidney injury (AKI) occurs in approximately half of patients in septic shock, and the mortality associated with sepsis-induced AKI is unacceptably high. Klotho is a protein expressed by renal cells and has anti-senescence properties. Klotho has also been shown to protect the kidneys in ischemia-reperfusion injury and to have antioxidant properties. To analyze the role of Klotho in sepsis-related organ dysfunction and AKI, we used a cecal ligation and puncture (CLP) model of sepsis in heterozygous Klotho-haploinsufficient mice and their wild-type littermates (CLP- Kl/+ and CLP-WT mice, respectively). In comparison with the CLP-WT mice, CLP- Kl/+ mice showed lower survival, impaired renal function, impaired hepatic function, greater oxidative stress, upregulation of inflammatory pathways (at the systemic and kidney tissue levels), and increased NF-κB activation. It is noteworthy that CLP- Kl/+ mice also showed lower heart-rate variability, less sympathetic activity, impaired baroreflex sensitivity to sodium nitroprusside, and a blunted blood pressure response to phenylephrine. We also demonstrated that sepsis creates a state of acute Klotho deficiency. Given that low Klotho expression exacerbates sepsis and multiple organ dysfunction, Klotho might play a protective role in sepsis, especially in elderly individuals in whom Klotho expression is naturally reduced.
Ipsilateral finger representations in the sensorimotor cortex are driven by active movement processes, not passive sensory input
Authors: Berlot Eva , Prichard George , O’Reilly Jill , Ejaz Naveed , Diedrichsen Jörn
Published: December 2018

Hand and finger movements are mostly controlled through crossed corticospinal projections from the contralateral hemisphere. During unimanual movements, activity in the contralateral hemisphere is increased while the ipsilateral hemisphere is suppressed below resting baseline. Despite this suppression, unimanual movements can be decoded from ipsilateral activity alone. This indicates that ipsilateral activity patterns represent parameters of ongoing movement, but the origin and functional relevance of these representations is unclear. In this study, we asked whether ipsilateral representations are caused by active movement or whether they are driven by sensory input. Participants alternated between performing single finger presses and having fingers passively stimulated while we recorded brain activity using high-field (7T) functional imaging. We contrasted active and passive finger representations in sensorimotor areas of ipsilateral and contralateral hemispheres. Finger representations in the contralateral hemisphere were equally strong under passive and active conditions, highlighting the importance of sensory information in feedback control. In contrast, ipsilateral finger representations in the sensorimotor cortex were stronger during active presses. Furthermore, the spatial distribution of finger representations differed between hemispheres: the contralateral hemisphere showed the strongest finger representations in Brodmann areas 3a and 3b, whereas the ipsilateral hemisphere exhibited stronger representations in premotor and parietal areas. Altogether, our results suggest that finger representations in the two hemispheres have different origins: contralateral representations are driven by both active movement and sensory stimulation, whereas ipsilateral representations are mainly engaged during active movement.

NEW & NOTEWORTHY Movements of the human body are mostly controlled by contralateral cortical regions. The function of ipsilateral activity during movements remains elusive. Using high-field neuroimaging, we investigated how human contralateral and ipsilateral hemispheres represent active and passive finger presses. We found that representations in contralateral sensorimotor cortex are equally strong during both conditions. Ipsilateral representations were mostly present during active movement, suggesting that sensorimotor areas do not receive direct sensory input from the ipsilateral hand.