bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimal Service Elasticity in Large-Scale Distributed Systems
Authors: Mukherjee Debankur , Dhara Souvik , Borst Sem C. , van Leeuwaarden Johan S.H. 
Published: March 2018

A fundamental challenge in large-scale cloud networks and data centers is to achieve highly efficient server utilization and limit energy consumption, while providing excellent user-perceived performance in the presence of uncertain and time-varying demand patterns. Auto-scaling provides a popular paradigm for automatically adjusting service capacity in response to demand while meeting performance targets, and queue-driven auto-scaling techniques have been widely investigated in the literature. In typical data center architectures and cloud environments however, no centralized queue is maintained, and load balancing algorithms immediately distribute incoming tasks among parallel queues. In these distributed settings with vast numbers of servers, centralized queue-driven auto-scaling techniques involve a substantial communication overhead and major implementation burden, or may not even be viable at all.Motivated by the above issues, we propose a joint auto-scaling and load balancing scheme which does not require any global queue length information or explicit knowledge of system parameters, and yet provides provably near-optimal service elasticity. We establish the fluid-level dynamics for the proposed scheme in a regime where the total traffic volume and nominal service capacity grow large in proportion. The fluid-limit results show that the proposed scheme achieves asymptotic optimality in terms of user-perceived delay performance as well as energy consumption. Specifically, we prove that both the waiting time of tasks and the relative energy portion consumed by idle servers vanish in the limit. At the same time, the proposed scheme operates in a distributed fashion and involves only constant communication overhead per task, thus ensuring scalability in massive data center operations. Extensive simulation experiments corroborate the fluid-limit results, and demonstrate that the proposed scheme can match the user performance and energy consumption of state-of-the-art approaches that do take full advantage of a centralized queue.
Towards Optimality in Parallel Scheduling
Authors: Berg Benjamin , Dorsman Jan-Pieter , Harchol-Balter Mor 
Published: March 2018

To keep pace with Moore's law, chip designers have focused on increasing the number of cores per chip rather than single core performance. In turn, modern jobs are often designed to run on any number of cores. However, to effectively leverage these multi-core chips, one must address the question of how many cores to assign to each job. Given that jobs receive sublinear speedups from additional cores, there is an obvious tradeoff: allocating more cores to an individual job reduces the job's runtime, but in turn decreases the efficiency of the overall system. We ask how the system should schedule jobs across cores so as to minimize the mean response time over a stream of incoming jobs.
To answer this question, we develop an analytical model of jobs running on a multi-core machine. We prove that EQUI, a policy which continuously divides cores evenly across jobs, is optimal when all jobs follow a single speedup curve and have exponentially distributed sizes. EQUI requires jobs to change their level of parallelization while they run. Since this is not possible for all workloads, we consider a class of "fixed-width" policies, which choose a single level of parallelization, k, to use for all jobs. We prove that, surprisingly, it is possible to achieve EQUI's performance without requiring jobs to change their levels of parallelization by using the optimal fixed level of parallelization, k*. We also show how to analytically derive the optimal k* as a function of the system load, the speedup curve, and the job size distribution.
In the case where jobs may follow different speedup curves, finding a good scheduling policy is even more challenging. In particular, we find that policies like EQUI which performed well in the case of a single speedup function now perform poorly. We propose a very simple policy, GREEDY*, which performs near-optimally when compared to the numerically-derived optimal policy.
DiagSim
Authors: Jo Jae-Eon , Lee Gyu-Hyeon , Jang Hanhwi , Lee Jaewon , Ajdari Mohammadamin , Kim Jangwoo 
Published: March 2018

Simulators are the most popular and useful tool to study computer architecture and examine new ideas. However, modern simulators have become prohibitively complex (e.g., 200K+ lines of code) to fully understand and utilize. Users therefore end up analyzing and modifying only the modules of interest (e.g., branch predictor, register file) when performing simulations. Unfortunately, hidden details and inter-module interactions of simulators create discrepancies between the expected and actual module behaviors. Consequently, the effect of modifying the target module may be amplified or masked and the users get inaccurate insights from expensive simulations.
In this article, we propose DiagSim, an efficient and systematic method to diagnose simulators. It ensures the target modules behave as expected to perform simulation in a healthy (i.e., accurate and correct) way. DiagSim is efficient in that it quickly pinpoints the modules showing discrepancies and guides the users to inspect the behavior without investigating the whole simulator. DiagSim is systematic in that it hierarchically tests the modules to guarantee the integrity of individual diagnosis and always provide reliable results. We construct DiagSim based on generic category-based diagnosis ideas to encourage easy expansion of the diagnosis.
We diagnose three popular open source simulators and discover hidden details including implicitly reserved resources, un-documented latency factors, and hard-coded module parameter values. We observe that these factors have large performance impacts (up to 156%) and illustrate that our diagnosis can correctly detect and eliminate them.
Ossabaw Pigs With a PCSK9 Gain‐of‐Function Mutation Develop Accelerated Coronary Atherosclerotic Lesions: A Novel Model for Preclinical Studies
Authors: Yuan Fang , Guo Liang , Park Kyoung‐Ha , Woollard John R. , Taek‐Geun Kwon , Jiang Kai , Melkamu Tamene , Zang Bin , Smith Samantha L. , Fahrenkrug Scott C. , Kolodgie Frank D. , Lerman Amir , Virmani Renu , Lerman Lilach O. , Carlson Daniel F. 
Published: March 2018

Background

Ossabaw pigs are unique miniature swine with genetic predisposition to develop metabolic syndrome and coronary atherosclerosis after extended periods receiving atherogenic diets. We have hypothesized that transgenic Ossabaw swine expressing chimp
PCSK9
(proprotein convertase subtilisin‐like/kexin type 9) containing the D374Y gain of function would develop familial hypercholesterolemia and coronary artery plaques more rapidly than Landrace swine with the same transgene.

Methods and Results

Ossabaw and Landrace
PCSK9
gain‐of‐function founders were generated by
Sleeping Beauty
transposition and cloning. Histopathologic findings in the Ossabaw founder animal showed more advanced plaques and higher stenosis than in the Landrace founder, underscoring the Ossabaw genetic predisposition to atherosclerosis. We chose to further characterize the Ossabaw
PCSK9
gain‐of‐function animals receiving standard or atherogenic diets in a 6‐month longitudinal study using computed tomography, magnetic resonance (MR) imaging, intravascular ultrasound, and optical coherence tomography, followed by pathological analysis of atherosclerosis focused on the coronary arteries. The Ossabaw model was consistently hypercholesterolemic, with or without dietary challenge, and by 6 months had consistent and diffuse fibrofatty or fibroatheromatous plaques with necrosis, overlying fibrous caps, and calcification in up to 10% of coronary plaques.

Conclusions

The Ossabaw
PCSK9
gain‐of‐function model provides consistent and robust disease development in a time frame that is practical for use in preclinical therapeutic evaluation to drive innovation. Although no animal model perfectly mimics the human condition, this genetic large‐animal model is a novel tool for testing therapeutic interventions in the context of developing and advanced coronary artery disease.
Attributes of Weathercasters Who Engage in Climate Change Education Outreach
Authors: Perkins IV David R. , Myers Teresa , Francis Zephi , Mazzone Raphael , Maibach Edward 
Published: March 2018

AbstractThis research explores the role of weathercasters as local climate change educators and identifies attributes of those who present climate science to their viewers. In 2015, the authors attempted to survey all television weathercasters currently working in the United States (n = 2128); 478 participated, yielding a 22.5% participation rate. Using logistic regression to identify attributes of weathercasters who report on climate change on-air, it was found that the strongest predictors were participation in Climate Matters (a climate change reporting resource program) (β = 1.01, p &lt; 0.001), personal interest in reporting on climate change (β = 0.93, p &lt; 0.001), age (higher rates of reporting among older weathercasters) (β = 0.301, p &lt; 0.05), and number of climate reporting interests (β = 1.37, p &lt; 0.05). Linear regression was used to identify attributes of weathercasters who showed the most interest in climate change reporting. Weathercasters most interested in reporting about climate change on-air were more certain that climate change is happening (β = 0.344, p &lt; 0.001), were convinced climate change is human caused (β = 0.226, p &lt; 0.001), were older (β = 0.157, p &lt; 0.001), and found the Third National Climate Assessment to be useful (β = 0.134, p &lt; 0.05). Weathercasters who are personally motivated to seek and share broad scientific information, acting as “station scientists,” appear to be those who are also proactive in sharing climate change information. Assisting motivated weathercasters with programs that reduce barriers to climate change education outreach complements their abilities to educate the public regarding climate change science.
Do selective serotonin reuptake inhibitors increase the risk of bleeding or mortality following coronary artery bypass graft surgery? A meta-analysis of observational studies
Authors: Eckersley Martyn J. , Sepehripour Amir H. , Casula Roberto , Punjabi Prakash , Athanasiou Thanos 
Published: March 2018

Introduction: Depressive illness has a high prevalence in patients undergoing coronary artery bypass graft surgery (CABG). The first line treatment for depression are selective serotonin reuptake inhibitors (SSRIs) which inhibit serotonin reuptake in the presynaptic neuronal membrane and uptake by platelets, inhibiting subsequent serotonin-mediated platelet activation. This presents a theoretically increased risk of bleeding and subsequent postoperative mortality. This review aims to investigate the effects of SSRIs on postoperative bleeding, defined as the need for transfusions and re-operation for bleeding, as well as 30-day mortality in patients undergoing CABG. Method: Four hundred and thirty-seven papers were screened with seven meeting the full inclusion criteria. Results: Meta-analysis demonstrated that SSRI use increased the risk of red blood cell transfusion (odds ratio (OR) = 1.15; 95% confidence interval (CI): 1.06-1.26), but resulted in no difference in the rate of re-operation for bleeding (OR = 1.07; 95% CI: 0.66-1.74). SSRI use had no effect on the rates of platelet (OR = 0.93; 95% CI: 0.79-1.09) or fresh frozen plasma (OR = 0.96; 95% CI: 0.74-1.24) transfusion nor on the mortality rate (OR =1.03; 95 CI: 0.90-1.17). Conclusion: This review demonstrates that SSRIs are largely safe in cardiac surgery as no increase in mortality was observed. However, there is a significantly raised chance of red blood cell transfusion. The heterogeneous nature of the current evidence base highlights the need for further research into SSRIs and whether any effect on patient outcomes in cardiac surgery occurs.
The use of behavioural theories in end-of-life care research: A systematic review
Authors: Scherrens Anne-Lore , Beernaert Kim , Robijn Lenzo , Deliens Luc , Pauwels Nele S , Cohen Joachim , Deforche Benedicte 
Published: March 2018

Background: It is necessary to understand behaviours that contribute to improvement in the quality of end-of-life care; use of behavioural theories allows identification of factors underlying end-of-life care behaviour, but little is known about the extent to which, and in what manner, these theories are used in an end-of-life care research context. Aim: To assess the number of end-of-life care studies that have used behavioural theories, which theories were used, to what extent main constructs were explored/measured and which behavioural outcomes were examined. Design: We conducted a systematic review. The protocol was registered on PROSPERO (CRD42016036009). Data sources: The MEDLINE (PubMed), PsycINFO, EMBASE, Web of Science and CINAHL databases were searched from inception to June 2017. We included studies aimed at understanding or changing end-of-life care behaviours and that explicitly referred to individual behavioural theories. Results: We screened 2231 records by title and abstract, retrieved 43 full-text articles and included 31 studies – 27 quantitative (of which four (quasi-)randomised controlled trials) and four qualitative – for data extraction. More than half used the Theory of Planned Behaviour (9), the Theory of Reasoned Action (4) or the Transtheoretical Model (8). In 9 of 31 studies, the theory was fully used, and 16 of the 31 studies focussed on behaviours in advance care planning. Conclusion: In end-of-life care research, the use of behavioural theories is limited. As many behaviours can determine the quality of care, their more extensive use may be warranted if we want to better understand and influence behaviours and improve end-of-life care.
Thoracic-abdominal imaging with a novel dual-layer spectral detector CT: intra-individual comparison of image quality and radiation dose with 128-row single-energy acquisition
Authors: Haneder Stefan , Siedek Florian , Doerner Jonas , Pahn Gregor , Grosse Hokamp Nils , Maintz David , Wybranski Christian 
Published: March 2018

Background A novel, multi-energy, dual-layer spectral detector computed tomography (SDCT) is commercially available now with the vendor’s claim that it yields the same or better quality of polychromatic, conventional CT images like modern single-energy CT scanners without any radiation dose penalty. Purpose To intra-individually compare the quality of conventional polychromatic CT images acquired with a dual-layer spectral detector (SDCT) and the latest generation 128-row single-energy-detector (CT128) from the same manufacturer. Material and Methods Fifty patients underwent portal-venous phase, thoracic-abdominal CT scans with the SDCT and prior CT128 imaging. The SDCT scanning protocol was adapted to yield a similar estimated dose length product (DLP) as the CT128. Patient dose optimization by automatic tube current modulation and CT image reconstruction with a state-of-the-art iterative algorithm were identical on both scanners. CT image contrast-to-noise ratio (CNR) was compared between the SDCT and CT128 in different anatomic structures. Image quality and noise were assessed independently by two readers with 5-point-Likert-scales. Volume CT dose index (CTDIvol), and DLP were recorded and normalized to 68 cm acquisition length (DLP68). Results The SDCT yielded higher mean CNR values of 30.0% ± 2.0% (26.4–32.5%) in all anatomic structures ( P < 0.001) and excellent scores for qualitative parameters surpassing the CT128 (all P < 0.0001) with substantial inter-rater agreement (κ ≥ 0.801). Despite adapted scan protocols the SDCT yielded lower values for CTDIvol (–10.1 ± 12.8%), DLP (−13.1 ± 13.9%), and DLP68 (–15.3 ± 16.9%) than the CT128 (all P < 0.0001). Conclusion The SDCT scanner yielded better CT image quality compared to the CT128 and lower radiation dose parameters.
The role of ARFI elastography to evaluate microstructrual changes of patients with testicular microlithiasis
Authors: Aslan Serdar , Ceyhan Bilgici Meltem , Saglam Dilek , Ozturk Mesut 
Published: March 2018

Background Testicular microlithiasis (TML) is thought to cause microstructural changes in the parenchyma of the testis, but it is difficult to demonstrate this by ultrasonography. It may be possible to evaluate microstructural changes in the testis by Acoustic Radiation Force Impulse (ARFI) elastography, which measures tissue stiffness. Purpose To assess the tissue stiffness of testicles of children with TML and to compare them with the healthy control group. Material and Methods Between November 2015 and May 2016, 25 pediatric patients with TML and 24 healthy children were enrolled in the study (mean age for TML and control group 6.7 ± 3.17 and 7.9 ± 4.18 years, respectively). Testicular volumes and mean shear wave velocity (SWV) values were calculated and compared with each other in both groups. Results There was no significant difference in average testicular volumes between the TML group and the control group (1.14 cm3, 1.21 cm3, respectively; P = 0.986). Mean SWV of the testicles with TML and normal testicles with control group was 1.18 ± 0.22 cm/s and 0.88 ± 0.11 cm/s, respectively. The SWV of the testicles with TML was higher than the normal testicles and this was statistically significant ( P < 0.001). Conclusion This study has shown that tissue stiffness in patients with TML is increased compared to the normal population. ARFI elastography helps the early detection of microstructural changes in TML and can be used for screening and follow-up.
The support needs and experiences of newly formed adoptive families: findings from the Wales Adoption Study
Authors: Meakings Sarah , Ottaway Heather , Coffey Amanda , Palmer Claire , Doughty Julie , Shelton Katherine 
Published: March 2018

This article reports on findings from the Wales Adoption Study which used a sequential, mixed-method design to explore the early support needs and experiences of newly formed adoptive families. Ninety-six adoptive parents completed a questionnaire four months post-placement and a sub-sample of 40 parents was interviewed in-depth five months thereafter. The main support needs of the families fell within five key domains: promoting children's health and development; strengthening family relationships; fostering children's identity; managing contact with birth parents and significant others; and financial and legal assistance. While the age and developmental stage of the child placed for adoption often influenced the nature of the support required across the various domains, the need for some form of support in every family was universal. Most, however, were not facing insurmountable difficulties. Arguably, many of the support needs identified could have been anticipated as they illustrate the complexities of ‘normal’ adoptive family life. The implications for social work practice are discussed.
Trends in Cigarette Advertising, Price-Reducing Promotions, and Policy Compliance in New York State Licensed Tobacco Retailers, 2004 to 2015
Authors: Watson Kimberly A. , Gammon Doris G. , Loomis Brett R. , Juster Harlan R. , Anker Elizabeth 
Published: March 2018

Purpose: To describe the presence of licensed tobacco retailers (LTRs), cigarette advertisements, price-reducing promotions, and compliance with tobacco control policies in New York State from 2004 to 2015 and to discuss implications and lessons learned from 11 years of experience conducting LTR surveys. Design: Annual surveys of tobacco advertising from cross-sectional, stratified random samples of LTRs in New York State from 2004 to 2015 were conducted by professional data collectors. Data for 2013 were unavailable as the survey was not fielded in that year. Setting: New York State. Participants: Licensed tobacco retailers, which are stores licensed to sell tobacco in the state of New York. Between 3.6% (n = 800) and 19.7% (n = 3945) of all LTRs were sampled annually. Measures: The presence and number of cigarette advertisements and the presence of price-reducing promotions, required age-of-sale signage, and self-service tobacco displays were documented. Analysis: We tested for significant differences between 2014 and 2015 and significant trends overall and by outlet type. We used logistic regression for binary outcomes and Poisson regression for count variables. Results: The number of LTRs in New York State decreased 22.9% from 2004 (n = 25 740) to 2015 (n = 19 855). The prevalence and number of cigarette advertisements and the prevalence of cigarette price-reducing promotions decreased significantly over time. Compliance with posting required age-of-sale signs increased significantly from 2004 to 2015 and from 2014 to 2015. Compliance with the ban on self-service tobacco displays was consistently near 100%. Conclusion: The tobacco retail environment in New York State improved substantially from 2004 to 2015. The implications of these findings for youth and adult smoking and the associated social costs are unknown; however, decreases in pro-tobacco marketing, decreases in the number of LTRs, and improvements in compliance are likely to have positive impacts on youth and adult smoking outcomes, such as reduced initiation and increased cessation, given previous research findings.
Effect of duration and severity of migraine on retinal nerve fiber layer, ganglion cell layer, and choroidal thickness
Authors: Abdellatif Mona K , Fouad Mohamed M 
Published: March 2018

Purpose: To investigate the factors in migraine that have the highest significance on retinal and choroidal layers’ thickness. Methods: Ninety patients with migraine and 40 age-matched healthy participants were enrolled in this observational, cross-sectional study. After full ophthalmological examination, spectral domain-optical coherence tomography was done for all patients measuring the thickness of ganglion cell layer and retinal nerve fiber layer. Enhanced depth imaging technique was used to measure the choroidal thickness. Results: There was significant thinning in the superior and inferior ganglion cell layers, all retinal nerve fiber layer quadrants, and all choroidal quadrants (except for the central subfield) in migraineurs compared to controls. The duration of migraine was significantly correlated with ganglion cell layer, retinal nerve fiber layer, and all choroidal quadrants, while the severity of migraine was significantly correlated with ganglion cell layer and retinal nerve fiber layer only. Multiregression analysis showed that the duration of migraine is the most important determinant factor of the superior retinal nerve fiber layer quadrant (β = −0.375, p = 0.001) and in all the choroidal quadrants (β = −0.531, −0.692, −0.503, −0.461, −0.564, respectively, p  < 0.001), while severity is the most important determinant factor of inferior, nasal, and temporal retinal nerve fiber layer quadrants (β = −0.256, −0.335, −0.308; p  = 0.036, 0.005, 0.009, respectively) and the inferior ganglion cell layer hemisphere (β = −0.377 and p = 0.001). Conclusion: Ganglion cell layer, retinal nerve fiber layer, and choroidal thickness are significantly thinner in patients with migraine. The severity of migraine has more significant influence in the thinning of ganglion cell layer and retinal nerve fiber layer, while the duration of the disease affected the choroidal thickness more.