bluuebunny/crossref_metadata_2025 huggingface dataset:
Sacred Cow Gone to Pasture: A Systematic Evaluation and Integration of Evidence‐Based Practice
Authors: Hanrahan Kirsten , Wagner Michele , Matthews Grace , Stewart Stephanie , Dawson Cindy , Greiner Joseph , Pottinger Jean , Vernon‐Levett Paula , Herold Debra , Hottel Rachel , Cullen Laura , Tucker Sharon , Williamson Ann
Published: January 2015

Background

Sacred cows (SC) are old habits in practice, considered routine and above dispute, regardless of evidence to the contrary.

Purpose

This is the first known report that aims to conduct a systematic evaluation of practices that have been described in the literature as SC and strategies for planned implementation of evidence‐based practices (EBP).

Methods

A large, complex, academic medical center department of nursing compared SC to EBP. Nurses systematically reviewed and rated the degree to which current practices adhered to best‐evidence versus SC. This initiative, “Sacred Cow: Gone to Pasture,” was developed, structured, and implemented according to the Iowa Model of Evidence‐Based Practice to Promote Quality Care, as well as Everett Rogers’ Diffusions of Innovations Theory. Implementation of EBP followed a phase plan using the Implementation Strategies for Evidence‐Based Practice to help to support adoption and integration.

Results

Review of organization‐specific policies and procedures and reports of actual practices revealed that SC persist, even in a center internationally recognized as a leader in EBP. The SC initiative caught the attention of busy clinicians, and raised awareness of SC and the importance of adherence to EBP. The SC initiative resulted in policy and practice changes and sparked new EBP and research, resulting in numerous improvements, including a significant decline in catheter‐associated urinary tract infections and shifting from basins to commercially prepared cloths for patient bathing.

Linking Evidence to Action

A strategic approach is crucial to eliminating SC and integrating EBP. This report calls nurses globally to action, to identify and abandon ineffective healthcare practices. Further research should compare and test the efficacy of implementation strategies, in particular how to sustain EBP in clinical settings.
Firm Performance and Business Cycles: Implications for Managerial Accountability
Authors: Suguri Motoki Fabio Yoshio , Carrasco Gutierrez Carlos Enrique
Published: January 2015

This study explores the relationship between firm performance and business cycles. These cycles are deviations from the trend of an economy-wide variable, in our case, GDP. Using a sample of Brazilian listed firms and accounting measures of performance, we find a generally positive contemporaneous relationship between the cycle and firm performance. Results also indicate that different industries show distinct relationships. This research presents a novel approach by linking firm performance from several industries to business cycles, indicating that managerial effort may be less determinant of firm performance than what is generally accepted. Our findings have potential implications for the design of more efficient compensation packages and to the study of managerial self-attributed performance.
An Experimental Study of the Flow Field Inside the Diffuser Passage of a Laboratory Centrifugal Pump
Authors: Si Qiaorui , Dupont Patrick , Bayeul-Lainé Annie-Claude , Dazin Antoine , Roussette Olivier , Yuan Shouqi
Published: January 2015

Measurements are processed on a centrifugal pump model, which works with air and performs with the vane-island type diffuser of a real hydraulic pump, under five flow rates to investigate the internal flow characteristics and their influence on overall pump performance. The mean flow characteristics inside the diffuser are determined by using a miniature three-hole probe connected to an online data acquisition system. The flow structure at the inlet section of the diffuser is analyzed in detail, with a focus on the local pressure loss inside the vaneless gap and incidence angle distributions along the hub-to-shroud direction of the diffuser. Some existing calculations, including leakage effects, are used to evaluate the pressure recovery downstream of the impeller. Furthermore, particle image velocimetry (PIV) measurement results are obtained to help analyze the flow characteristics inside the vane-island diffuser. Each PIV measuring plane is related to one particular diffuser blade-to-blade channel and is analyzed by using the time-averaged method according to seven different relative positions of the impeller. Measurement results show that main loss is produced inside the vaneless part of the diffuser at low flow rates, which might have been caused by the strong rotor–stator interaction. When the impeller flow rate is greater than the diffuser design flow rate, a large fluctuating separated region occurs after the throat of the diffuser on the pressure side. Mean loss originates from the unsteady pressure downstream of the diffuser throat. For better characterization of the separations observed in previous experimental studies, complementary unsteady static pressure measurement campaigns have been conducted on the diffuser blade wall. The unsteadiness revealed by these measurements, as well as theirs effects on the diffuser performance, was then studied.
Forced Convection Cooling of Low-Power Handheld Devices Using a Vibrating Cantilever Beam
Authors: Kim Jangwoo , Ro Paul I.
Published: January 2015

In this study, a convection cooling technique for handheld electronic devices is proposed and investigated. The technique uses bulk airflows generated by a vibrating cantilever beam actuated by a rotating imbalance motor. Analytic coupled physics modeling using an approximate integral method within laminar-flow boundary layers was used to analyze the proposed cooling technique. The cantilever beam and enclosure were designed based on the form factors of a typical handheld device. The bulk airflow cooling performances at various probe locations were investigated experimentally for low and high heating loads and numerically verified. The results indicate that a higher heating load of the heat source results in a larger temperature drop at the same convection rate. Also, for the probe locations away from the heat source and closer to the beam, the resulting temperature drops were relatively small despite a stronger velocity field generated by the beam. This is due first to the heat generated by the vibrating beam itself and second to a circulation of the air heated by the heat source to the rest of the regions in the enclosure. In general, a good agreement between experimental and numerical results was attained, even though a slight difference between two results exists. Overall, significant cooling was achieved by the proposed system. With a beam tip deflection of ±4 mm, nearly an 18-fold increase in the cooling performance was achieved compared to a natural convection case. Furthermore, the cooling performance continues to increase as the tip deflection of the cantilever beam increases. Thus, a cooling system using the bulk airflow generated by a vibrating cantilever beam has much potential as a feasible solution for electronic handheld devices.
3D calculation of radiation‐induced second cancer risk including dose and tissue response heterogeneities
Authors: Timlin C. , Warren D. R. , Rowland B. , Madkhali A. , Loken J. , Partridge M. , Jones B. , Kruse J. , Miller R.
Published: January 2015

Purpose:

Tools for comparing relative induced second cancer risk, to inform choice of radiotherapy treatment plan, are becoming increasingly necessary as the availability of new treatment modalities expands. Uncertainties, in both radiobiological models and model parameters, limit the confidence of such calculations. The aim of this study was to develop and demonstrate a software tool to produce a malignant induction probability (MIP) calculation which incorporates patient‐specific dose and allows for the varying responses of different tissue types to radiation.

Methods:

The tool has been used to calculate relative MIPs for four different treatment plans targeting a subtotally resected meningioma: 3D conformal radiotherapy (3DCFRT), volumetric modulated arc therapy (VMAT), intensity‐modulated x‐ray therapy (IMRT), and scanned protons.

Results:

Two plausible MIP models, with considerably different dose–response relationships, were considered. A fractionated linear–quadratic induction and cell‐kill model gave a mean relative cancer risk (normalized to 3DCFRT) of 113% for VMAT, 16% for protons, and 52% for IMRT. For a linear no‐threshold model, these figures were 105%, 42%, and 78%, respectively. The relative MIP between plans was shown to be significantly more robust to radiobiological parameter uncertainties compared to absolute MIP. Both models resulted in the same ranking of modalities, in terms of MIP, for this clinical case.

Conclusions:

The results demonstrate that relative MIP is a useful metric with which treatment plans can be ranked, regardless of parameter‐ and model‐based uncertainties. With further validation, this metric could be used to discriminate between plans that are equivalent with respect to other planning priorities.
I spy alloreactive T cells
Authors: Alegre Maria-Luisa
Published: January 2015

Longitudinal tracking of alloreactive T cells in kidney transplant patients with high-throughput sequencing highlighted clonal deletion as a mechanism of transplantation tolerance.
Healing with medical implants: The body battles back
Authors: Ratner Buddy D.
Published: January 2015

Disease or inflammation can have substantial impact on biomaterials performance and the loosely defined term “biocompatibility” (Oliva
et al
., this issue).
TRIPOD puts prediction models on a firmer footing
Authors: Drum Chester L.
Published: January 2015

International standards for clinical prediction models should improve the quality of reporting.
Putative E3 Ubiquitin Ligase of Human Rotavirus Inhibits NF-κB Activation by Using Molecular Mimicry To Target β-TrCP
Authors: Morelli Marco , Dennis Allison F. , Patton John T.
Published: January 2015

NF-κB plays a critical role in the induction and maintenance of innate and adaptive immune transcriptional programs. An associated inhibitor of κB protein (IκB) regulates NF-κB activation and contains a degron motif (DSGΦxS) that undergoes phosphorylation following pathogen recognition or other proinflammatory signals. The E3 ubiquitin ligase SCF
β-TrCP
recognizes this phosphodegron through its β-transducin repeat-containing protein (β-TrCP) subunit and induces IκB degradation, allowing NF-κB to translocate to the nucleus and modulate gene expression. Rotavirus (RV), a major cause of pediatric gastroenteritis, can block NF-κB activation through the action of its nonstructural protein NSP1, a putative E3 ubiquitin ligase that mediates the degradation of β-TrCP or other immunomodulatory proteins in a virus strain-specific manner. Here, we show that NSP1 targets β-TrCP by mimicking the IκB phosphodegron. The NSP1 proteins of most human and porcine RV strains conserve a C-terminal phosphodegron-like (PDL) motif, DSGΦS. Deletion of this motif or mutation of its serine residues disrupts NSP1-mediated degradation of β-TrCP and inhibition of NF-κB activation. Additionally, a point mutation within the phosphodegron-binding pocket protects β-TrCP from NSP1-mediated turnover. Fusion of the PDL motif to an NSP1 protein known to target other immunomodulatory proteins generates a chimeric NSP1 protein that can induce β-TrCP degradation and block NF-κB activation. Other viral proteins (Epstein-Barr virus LMP1, HIV-1 Vpu, and vaccinia virus A49) also contain a PDL motif and interact with β-TrCP to inhibit NF-κB activation. Taken together, these data suggest that targeting β-TrCP by molecular mimicry may be a common strategy used by human viruses to evade the host immune response.

IMPORTANCE
   The transcription factor NF-κB, a central regulator of the host response to infection, is a frequent target of viral antagonism. Pathogen detection activates NF-κB by inducing the phosphorylation of an associated inhibitor protein (IκB), which targets IκB for degradation by the E3 ubiquitin ligase β-TrCP. Rotavirus, a significant cause of childhood gastroenteritis, antagonizes NF-κB through the activity of its NSP1 protein, a putative E3 ubiquitin ligase that mediates β-TrCP turnover. Here, we show that NSP1 functions by mimicking the IκB phosphodegron recognized by β-TrCP. Nearly all human rotavirus strains conserve this motif at the NSP1 C terminus, and its removal disrupts NSP1 antagonist activity. This sequence conserves the biochemical properties of the IκB phosphodegron and can rescue antagonist activity when fused to an NSP1 protein otherwise inactive against β-TrCP. Other viral proteins also mimic IκB to disrupt NF-κB activation, indicating that this is an important immune evasion strategy.
Psoas abscess and severe fasciitis due to a caecal carcinoma
Authors: Ng Nigel Yong Boon , Twoon Mark , Thomson Suzanne E
Published: January 2015

A man in his mid-50s presented with a painful and swollen right thigh and buttock. This was accompanied by a month long history of flank pain, back pain, vague abdominal pain, limp, fever and weight loss. On examination, there was extensive erythaema, heat, tenderness, oedema and crepitus over his right buttock and thigh. The patient was referred to plastic surgery to exclude necrotising fasciitis of the gluteal and thigh region. After CT imaging, a psoas abscess (PA) and caecal mass were identified. Subsequent right hemicolectomy, PA drainage and debridement of his right thigh were performed. This case reminds clinicians of the many non-specific ways a PA can present and that a high level of suspicion assists in making a timely diagnosis.
Evidence of and recommendations for non-pharmacological interventions for common geriatric conditions: the SENATOR-ONTOP systematic review protocol
Authors: Abraha Iosief , Cruz-Jentoft Alfonso , Soiza Roy L , O'Mahony Denis , Cherubini Antonio
Published: January 2015

Introduction

Non-pharmacological therapies for common chronic medical conditions in older patients are underused in clinical practice. We propose a protocol for the assessment of the evidence of non-pharmacological interventions to prevent or treat relevant outcomes in several prevalent geriatric conditions in order to provide recommendations.

Methods and analysis

The conditions of interest for which the evidence about efficacy of non-pharmacological interventions will be searched include delirium, falls, pressure sores, urinary incontinence, dementia, heart failure, orthostatic hypotension, sarcopaenia and stroke. For each condition, the following steps will be undertaken: (A) prioritising clinical questions; (B) retrieving the evidence (MEDLINE, the Cochrane Library, CINAHL and PsychINFO will be searched to identify systematic reviews); (C) assessing the methodological quality of the evidence (risk of bias according to the Cochrane method will be applied to the primary studies retrieved from the systematic reviews); (D) developing recommendations based on the evidence (Grading of Recommendations Assessment, Development and Evaluation (GRADE) items—risk of bias, imprecision, inconsistency, indirectness and publication bias—will be used to rate the overall evidence and develop recommendations).

Dissemination

For each target condition, at least one systematic overview concerning the evidence of non-pharmacological interventions will be produced and published in peer-reviewed journals.
Periprocedural safety of aneurysm embolization with the Medina Coil System: the early human experience
Authors: Turk Aquilla S , Maia Orlando , Ferreira Christian Candido , Freitas Diogo , Mocco J , Hanel Ricardo
Published: January 2015

Introduction

Intracranial saccular aneurysms, if untreated, carry a high risk of morbidity and mortality from intracranial bleeding. Embolization coils are the most common treatment. We describe the periprocedural safety and performance of the initial human experience with the next generation Medina Coil System.

Methods

The Medina Coil System is a layered three-dimensional coil made from a radiopaque, shape set core wire, and shape memory alloy outer coil filaments. Nine aneurysms in five patients were selected for treatment with the Medina Coil System.

Results

Nine aneurysms in five patients, ranging from 5 to 17 mm in size in various locations, were treated with the Medina Coil System. No procedural or periprocedural complications were encountered. Procedure times, number of coils used to treat the aneurysm, and use of adjunctive devices were much less than anticipated if conventional coil technology had been used.

Conclusions

The Medina Coil System is a next generation coil that combines all of the familiar and expected procedural safety and technique concepts associated with conventional coils. We found improved circumferential aneurysm filling, which may lead to improved long term outcomes, with fewer devices and faster operating times.
Measuring shear wave velocity of granular material using the piezoelectric ring-actuator technique (P-RAT)
Authors: Karray Mourad , Ben Romdhan Mohamed , Hussien Mahmoud N. , Éthier Yannic
Published: January 2015

A precise evaluation of shear wave velocity, Vs, is a crucial issue in the design of foundations subjected to dynamic loading, liquefaction evaluation, and soil improvement control. Laboratory techniques such as resonant column (RC) and bender element (BE) have been developed over the years to measure Vs. At low strain (γ < 10−3), techniques based on piezoelectric elements (e.g., BE) can be considered superior to RC, as they can be used in conventional geotechnical devices (e.g., triaxial, oedometer, direct simple shear, etc.). However, it is a difficult task to verify that the obtained Vsvalues are correct and accurate, as there are several difficulties associated with these methods, including the mixed radiation of both primary and shear waves, near-field effects, boundary effects, and uncertain detection of first arrivals. This paper presents the use of a new technique to measure Vsin granular material, called the piezoelectric ring-actuator technique (P-RAT), developed at the Université de Sherbrooke. The paper also provides a detailed description of a unique interpretation method of the signals produced from this technique to minimize the difficulties associated with other techniques. The P-RAT has been incorporated into the well-known oedometer cell to measure the Vsof Péribonka sand through a series of oedometric tests, and the obtained results have been detailed, analyzed, and discussed in light of the basic state of knowledge of Vsand factors affecting it. Particular emphasis is also placed on the validation of the accuracy of the P-RAT by means of reliable experimental measurements available in literature.
Lanthanide-dependent RNA-cleaving DNAzymes as metal biosensors
Authors: Liu Juewen
Published: January 2015

Lanthanides represent a group of very important but challenging analytes for biosensor development. These 15 elements are very similar in their chemical properties. So far, limited success has been realized using the rational ligand design approach. My laboratory has successfully accomplished the task of carrying out combinatorial selection to isolate lanthanide-dependent RNA-cleaving DNAzymes. We report two new DNAzymes, each discovered in a different selection condition and both are highly specific to lanthanides. When both DNAzymes are used together, it is possible to identify the last few heavy lanthanides. Upon introducing a phosphorothioate modification, one of the abovementioned DNAzymes becomes highly active with many toxic heavy metals. With the selection of more DNAzymes with different activity patterns cross the lanthanide series, a sensor array might be produced for identifying each ion. This article is a minireview of the current developments on this topic and some of the historical aspects. It reflects the main content of the Fred Beamish Award presentation delivered at the 2014 Canadian Society for Chemistry Conference in Vancouver. Future directions in this area are also discussed.
Vitamin D3 analogs for the treatment of osteoporosis
Authors: Hagino Hiroshi
Published: January 2015

Vitamin D supplementation is recommended whenever patients are given therapeutic drugs for osteoporosis, to make their calcium (Ca) balance positive. Vitamin D is converted to 25-hydroxyvitamin D in the liver, and then activated to become 1α,25-dihydroxyvitamin D in the kidneys. The active vitamin D acts in the intestine to stimulate Ca absorption and maintain the Ca balance. 2β-(3-Hydroxypropyloxy)-1α,25-dihydroxyvitamin D3 (eldecalcitol) and 2-methylene-19-nor-(20S)-1α,25-dihydroxyvitamin D3 (2MD) are newly developed vitamin D analogs, with a substitution at the 2 position of 1α,25-dihydroxyvitamin D3 (calcitriol). Eldecalcitol and 2MD share common structural and biological characteristics. Both compounds increase serum Ca levels more markedly than calcitriol, increase bone mineral density (BMD), and improve bone strength in ovariectomized (OVX) rats. In a randomized, placebo-controlled, double-blind, 1 year clinical trial, eldecalcitol dose-dependently increased lumbar and hip BMD and suppressed bone turnover markers in patients with osteoporosis. Whereas, 2MD markedly increased the bone turnover markers, but it did not change the BMD of postmenopausal women with osteopenia in a 1 year clinical trial. After a randomized, double-blind, 3 year fracture-prevention trial comparing it with alfacalcidol, eldecalcitol was approved for the treatment of osteoporosis in Japan. On the other hand, the manufacturer discontinued the clinical development of 2MD. In this review, we discuss the similarities and differences between these 2 compounds, and the reasons why different outcomes resulted from their clinical trials.
Effect of oxidative stress on Rho kinase II and smooth muscle contraction in rat stomach
Authors: Al-Shboul Othman , Mustafa Ayman
Published: January 2015

Recent studies have shown that both Rho kinase signaling and oxidative stress are involved in the pathogenesis of a number of human diseases, such as diabetes mellitus, hypertension, and atherosclerosis. However, very little is known about the effect of oxidative stress on the gastrointestinal (GI) smooth muscle Rho kinase pathway. The aim of the current study was to investigate the effect of oxidative stress on Rho kinase II and muscle contraction in rat stomach. The peroxynitrite donor 3-morpholinosydnonimine (SIN-1), hydrogen peroxide (H2O2), and peroxynitrite were used to induce oxidative stress. Rho kinase II expression and ACh-induced activity were measured in control and oxidant-treated cells via specifically designed enzyme-linked immunosorbent assay (ELISA) and activity assay kits, respectively. Single smooth muscle cell contraction was measured via scanning micrometry in the presence or absence of the Rho kinase blocker, Y-27632 dihydrochloride. All oxidant agents significantly increased ACh-induced Rho kinase II activity without affecting its expression level. Most important, oxidative stress induced by all three agents augmented ACh-stimulated muscle cell contraction, which was significantly inhibited by Y-27632. In conclusion, oxidative stress activates Rho kinase II and enhances contraction in rat gastric muscle, suggesting an important role in GI motility disorders associated with oxidative stress.
Relaying propensity and characteristics of replacement clutches of Leach’s Storm-Petrels (Oceanodroma leucorhoa)
Authors: Bond Alexander L. , Hobson Keith A.
Published: January 2015

Animals with low fecundity, such as seabirds, invest heavily into one or a few eggs per breeding attempt. The loss of these eggs can mean that individuals abandon breeding or invest in a replacement clutch. However, the ability of females to replace clutches may be costly and so replacement clutches may be delayed and they may differ in nutrient content. Replacement clutches are rarely documented conclusively in storm-petrels, and most avian replacement clutches are smaller and differ in composition from original eggs. We removed eggs from Leach’s Storm-Petrel (Oceanodroma leucorhoa (Vieillot, 1818)) nests on Gull Island, Witless Bay, Newfoundland and Labrador, Canada, and monitored nest sites for replacement clutches. Leach’s Storm-Petrels use locally acquired nutrients to lay a single egg that weighs 20% of a female’s body mass. Nearly 70% of pairs (17/26) produced a replacement egg after 22 days and two pairs produced a third egg after a further 21 days. Replacement eggs were nearly identical to original clutches, except for small decreases in length (2%) and volume (3%). We found that Leach’s Storm-Petrels were able to acquire sufficient nutrients to produce a second (and in two cases, a third) egg, likely from endogenous nutrients, but delays of 3–6 weeks in breeding may have detrimental effects on fledging success and offspring survival.
Lattice gauge theory and gluon color-confinement in curved spacetime
Authors: Villegas Kristian Hauser , Esguerra Jose Perico
Published: January 2015

The lattice gauge theory (LGT) for curved spacetime is formulated. A discretized action is derived for both gluon and quark fields which reduces to the generally covariant form in the continuum limit. Using the Wilson action, it is shown analytically that for a general curved spacetime background, two propagating gluons are always color-confined. The fermion-doubling problem is discussed in the specific case of Friedman–Robertson–Walker (FRW) metric. Last, we discussed possible future numerical implementation of lattice QCD in curved spacetime.
Fabrication and characterization of a-oriented TbFeO3/Nb-doped SrTiO3 heterostructure
Authors: Li P. G. , Li W. L. , Zhang M. , An Y. H. , Guo D. Y. , Wu Z. P. , Lei M. , Wang S. L. , Shen J. Q. , Xiao J. H. , Tang W. H.
Published: January 2015

The a-axis oriented TbFeO 3, (TFO) thin film was epitaxially grown on (001) Nb-1 wt.%-doped SrTiO 3 (Nb–STO) single crystal substrate to construct a heterostructure. The heterostructure exhibited a good rectifying behavior over the temperature range of 25–300 K, and the rectification ratio was continuously enhanced with increasing temperature. In positive bias direction, transport mechanism of the heterostructure showed a crossover from the Schottky-emission-like to a space-charge-limited type at 120 K, the temperature at which the TFO shows a magnetic ordering, while in the negative bias direction it was solely dominated by the space-charge-limited mechanism. The result indicates that coupling between electrical and magnetic orders can influence the rectifying behavior of the heterostructure. The observation hints the possibility to tune rectifying properties of a heterostructure via influencing magnetic properties of the magnetic layer.
Spin polarization of polaron in quasi-one dimensional organic system
Authors: Jiang Hong , Zhang Chao , Hu Xuening , Hu Guichao , Xie Shijie
Published: January 2015

The spin polarization of polarons in quasi-1D organic materials has been investigated by using the extended Su–Schrieffer–Heeger (SSH) model with spin-orbit coupling. Results show that the polaron is partly spin polarized, and that the electron–electron interaction and spin-orbit coupling compete with each other during the formation of spin polarization. The dependence of spin polarization on electron–phonon coupling is also revealed. Our results demonstrate that spin polarization is well correlated with polaron localization, thus providing useful guidance for exploring magnetic effects in organic materials.
Structural properties of coal metallic glasses investigated by molecular dynamics simulations
Authors: Xia J. H. , Gao Xue-mei , Xiao Xu-yang , Cheng Zheng-fu
Published: January 2015

Based on using molecular dynamics simulations, the structural transitions of Co 25 Al 75 and Co 75 Al 25 were studied during two different quenching processes. The pair-correlation function, the Honeycutt–Andersen (HA) pair analysis technique, Voronoi indices and structural snapshot are adopted in both rapid quenching processes. The results provide direct evidence of the liquid–crystal transition and the liquid Co 75 Al 25 crystallizes into bcc phase at 300 K during the rapid quenching process r1 = 1 K/ps. While during the rapid quenching r2 = 10 K/ps the liquid is frozen into the glass state at 300 K. Meanwhile, the liquid Co 25 Al 75 is frozen into the glass state at 300 K during the two rapid quenching processes. Our results show that the phase formation is strongly dependent on the cooling rates and the compositions.
CHEMICAL, MECHANICAL AND HYDRODYNAMIC PROPERTIES RESEARCH ON COMPOSITE DRAG REDUCTION SURFACE BASED ON BIOLOGICAL SHARKSKIN MORPHOLOGY AND MUCUS NANOLONG CHAIN
Authors: LUO YUEHAO , ZHANG DEYUAN , LIU YUFEI , LI YUANYUE , NG E. Y. K.
Published: January 2015

Natural selection, survival of the fittest. Through millions of years' evolution, shark has become one of the fastest swimming animals in the ocean, and it is very well-known for sharkskin effect, especially for "sharkskin swimsuit". Due to its great superior properties in drag reduction, anti-wear, self-cleaning and so on, the investigations on the essential mechanisms and fabricating methods have attracted so much attention from all over the world, and the achievements have been widely put into application in industry, agriculture, transportation, airspace and so on, and so lots of profits have been obtained so far. In this paper, the method of fabricating artificial composite drag reduction surface based on biological sharkskin morphology and mucus nano-long chain is investigated and studied, the chemical, mechanical and hydrodynamic properties are explored from different aspects in depth, in which, the experimental results in water tunnel showed that the drag-reducing efficiency could surpass 20% with the smooth skin as reference, and the drag reduction mechanism is systematically explained and discussed from different aspects, which has important significance to understand the recent research status and expand the applications of sharkskin in the fluid engineering.
Getting to the Shalls
Authors: Chakraborty Suranjan , Rosenkranz Christoph , Dehlinger Josh
Published: January 2015

Sensemaking in Requirements Engineering (RE) relies on knowledge transfer, communication, and negotiation of project stakeholders. It is a critical and challenging aspect of Information Systems (IS) development. One of the most fundamental aspects of RE is the specification of traceable, unambiguous, and operationalizable functional and nonfunctional requirements. This remains a nontrivial task in the face of the complexity inherent in RE due to the lack of well-documented, systematic procedures that facilitate a structured analysis of the qualitative data from stakeholder interviews, observations, and documents that are typically the input to this activity. This research develops a systematic and traceable procedure, for non-functional requirements the Grounded and Linguistic-Based Requirements Analysis Procedure (GLAP), which can fill this gap by incorporating perspectives from Grounded Theory Method, linguistic analysis of language quality, Volere typology, and the Nonfunctional Requirements Framework without significantly deviating from existing practice. The application of GLAP is described along with empirical illustrations using RE data from a redesign initiative of a library website of a public university in the United States. An outlook is given on further work and necessary evaluation steps.
Editorial
Authors: Jarke Matthias , Lyytinen Kalle
Published: January 2015

Walking on water, and programming according to specifications is easy—as long as both of them are frozen.
--Robert Glass

This introduction discusses the changing nature of complexity associated with requirements engineering (RE) tasks and how it has shifted from managing internal complexity to adapting and leveraging upon external and dynamic complexity. We note several significant drivers in the requirements knowledge that have resulted in this change and discuss in light of complexity theory how the RE research community can respond to this. We observe several research challenges associated with “new complexity” and highlight how the articles included in the special issue advance the field by defining complexity more accurately, observing more vigilantly new sources of complexity, and suggesting new ways to manage complexity in terms of economic assessments, knowledge flows, and modeling for adaptability.
A Software Scheme for Multithreading on CGRAs
Authors: Pager Jared , Jeyapaul Reiley , Shrivastava Aviral
Published: January 2015

Recent industry trends show a drastic rise in the use of hand-held embedded devices, from everyday applications to medical (e.g., monitoring devices) and critical defense applications (e.g., sensor nodes). The two key requirements in the design of such devices are their processing capabilities and battery life. There is therefore an urgency to build high-performance and power-efficient embedded devices, inspiring researchers to develop novel system designs for the same. The use of a coprocessor (application-specific hardware) to offload power-hungry computations is gaining favor among system designers to suit their power budgets. We propose the use of CGRAs (Coarse-Grained Reconfigurable Arrays) as a power-efficient coprocessor. Though CGRAs have been widely used for streaming applications, the extensive compiler support required limits its applicability and use as a general purpose coprocessor. In addition, a CGRA structure can efficiently execute only one statically scheduled kernel at a time, which is a serious limitation when used as an accelerator to a multithreaded or multitasking processor. In this work, we envision a multithreaded CGRA where multiple schedules (or kernels) can be executed simultaneously on the CGRA (as a coprocessor). We propose a comprehensive software scheme that transforms the traditionally single-threaded CGRA into a multithreaded coprocessor to be used as a power-efficient accelerator for multithreaded embedded processors. Our software scheme includes (1) a compiler framework that integrates with existing CGRA mapping techniques to prepare kernels for execution on the multithreaded CGRA and (2) a runtime mechanism that dynamically schedules multiple kernels (offloaded from the processor) to execute simultaneously on the CGRA coprocessor. Our multithreaded CGRA coprocessor implementation thus makes it possible to achieve improved power-efficient computing in modern multithreaded embedded systems.
System-Level Performance and Power Optimization for MPSoC
Authors: Lin Ye-Jyun , Yang Chia-Lin , Huang Jiao-We , Lin Tay-Jyi , Hsueh Chih-Wen , Chang Naehyuck
Published: January 2015

As the number of IPs in a multimedia Multi-Processor System-on-Chip (MPSoC) continues to increase, concurrent memory accesses from different IPs increasingly stress memory systems, which presents both opportunities and challenges for future MPSoC design. The impact of such requirements on the system-level design for MPSoC is twofold. First, contention among IPs prolongs memory access time, which exacerbates the persisting memory wall problem. Second, longer memory accesses lead to longer IP stall time, which results in unnecessary leakage waste. In this article, we propose two memory access-aware system-level design approaches for performance and leakage optimization. To alleviate the memory wall problem, we propose a Hierarchical Memory Scheduling (HMS) policy that schedules memory requests from the same IP and application consecutively to reduce interference among memory accesses from different IPs with a fairness guarantee. To reduce IP leakage waste due to long memory access, we propose a memory access-aware power-gating policy. A straightforward power-gating approach is to power gate an IP when it needs to fetch data from memory. However, due to the response time variation among memory accesses, aggressively power gating an IP whenever a memory request occurs may result in incorrect power-gating decisions. The proposed memory access-aware power-gating policy makes these decisions judiciously, based on the predicted memory latency of an individual IP and its energy breakeven time. The experimental results show that the proposed HMS memory scheduling policy improves system throughput by 42% compared to First-Come-First-Serve (FCFS) and by 21% compared to First-Ready First-Come-First-Serve (FR-FCFS) on an MPSoC for mobile phones. For the improvement of fairness, HMS improves fairness by 1.52× compared to FCFS and by 1.23× compared to FRFCFS. In the aspect of leakage optimization, our memory access-aware power-gating mechanism improves energy savings by 3.88× and reduces the performance penalty by 70% compared to conventional timeout-based power gating. We further demonstrate that our HMS memory scheduler can regulate memory access orders, thereby reducing memory response time variation. This leads to more accurate power-down decisions for both conventional timeout power gating and the proposed memory access- aware power gating.
Mechanistic Modeling of Architectural Vulnerability Factor
Authors: Nair Arun Arvind , Eyerman Stijn , Chen Jian , John Lizy Kurian , Eeckhout Lieven
Published: January 2015

Reliability to soft errors is a significant design challenge in modern microprocessors owing to an exponential increase in the number of transistors on chip and the reduction in operating voltages with each process generation. Architectural Vulnerability Factor (AVF) modeling using microarchitectural simulators enables architects to make informed performance, power, and reliability tradeoffs. However, such simulators are time-consuming and do not reveal the microarchitectural mechanisms that influence AVF. In this article, we present an accurate first-order mechanistic analytical model to compute AVF, developed using the first principles of an out-of-order superscalar execution. This model provides insight into the fundamental interactions between the workload and microarchitecture that together influence AVF. We use the model to perform design space exploration, parametric sweeps, and workload characterization for AVF.
Stubborn Sets for Time Petri Nets
Authors: Boucheneb Hanifa , Barkaoui Kamel
Published: January 2015

The main limitation of the verification approaches based on state enumeration is the state explosion problem. The partial order reduction techniques aim at attenuating this problem by reducing the number of transitions to be fired from each state while preserving properties of interest. Among the reduction techniques proposed in the literature, this article considers the stubborn set method of Petri nets and investigates its extension to time Petri nets. It establishes some useful sufficient conditions for stubborn sets, which preserve deadlocks and k-boundedness of places.
Foreword
Authors: Eide Eric
Published: January 2015

Welcome to this special issue of Operating Systems Review dedicated to the topics of repeatability and sharing of experimental artifacts in systems research. The twelve papers in this issue present na snapshot of activities, results, and viewpoints on this theme. As the guest editor of this issue, I hope that you find these papers to be both inspiring and useful. I hope that by reading them, you will be motivated to carefully think about repeatability and artifact sharing as you pursue your own systems experiments. Several of the papers in this special issue present tools or testbeds that support repeatability and sharing, so I expect that you will discover one or more "new tricks" that will make it easier for you to create and share high-quality, sound, and repeatable experiments.
An introduction to Docker for reproducible research
Authors: Boettiger Carl
Published: January 2015

As computational work becomes more and more integral to many aspects of scientific research, computational reproducibility has become an issue of increasing importance to computer systems researchers and domain scientists alike. Though computational reproducibility seems more straight forward than replicating physical experiments, the complex and rapidly changing nature of computer environments makes being able to reproduce and extend such work a serious challenge. In this paper, I explore common reasons that code developed for one research project cannot be successfully executed or extended by subsequent researchers. I review current approaches to these issues, including virtual machines and workflow systems, and their limitations. I then examine how the popular emerging technology Docker combines several areas from systems research - such as operating system virtualization, cross-platform portability, modular re-usable elements, versioning, and a 'DevOps' philosophy, to address these challenges. I illustrate this with several examples of Docker use with a focus on the R statistical environment.
Creating Repeatable Computer Science and Networking Experiments on Shared, Public Testbeds
Authors: Edwards Sarah , Liu Xuan , Riga Niky
Published: January 2015

There are many compelling reasons to use a shared, public testbed such as GENI, Emulab, or PlanetLab to conduct experiments in computer science and networking. These testbeds support creating experiments with a large and diverse set of resources. Moreover these testbeds are constructed to inherently support the repeatability of experiments as required for scientifically sound research. Finally, the artifacts needed for a researcher to repeat their own experiment can be shared so that others can readily repeat the experiment in the same environment.

However using a shared, public testbed is different from conducting experiments on resources either owned by the experimenter or someone the experimenter knows. Experiments on shared, public testbeds are more likely to use large topologies, use scarce resources, and need to be tolerant to outages and maintenances in the testbed. In addition, experimenters may not have access to low-level debugging information.

This paper describes a methodology for new experimenters to write and deploy repeatable and sharable experiments which deal with these challenges by: having a clear plan; automating the execution and analysis of an experiment by following best practices from software engineering and system administration; and building scalable experiments. In addition, the paper describes a case study run on the GENI testbed which illustrates the methodology described.
A Roadmap and Plan of Action for Community-Supported Empirical Evaluation in Computer Architecture
Authors: Childers Bruce R. , Jones Alex K. , Mossé Daniel
Published: January 2015

A framework of open interoperable simulators for computer architecture is long overdue. Today there are many separate, uncoordinated efforts to develop simulation and modeling artifacts (tools) for computer architecture research. The artifacts are used to empirically evaluate new computer architecture innovations and compare them with the state of the art. The artifacts are usually developed by individual groups, often for a specific purpose, and may not be publicly released. Consequently, it is difficult to leverage investment in artifact development and to repeat or reproduce experiments. In this position paper, we present recommendations and a roadmap for sharing and building open-source, interoperable simulation and modeling artifacts. The recommendations are the outcome of a community workshop involving industry, government and academia to determine how to coordinate effort, share tools and improve methodology.
Task assignment with energy efficiency considerations for non-DVS heterogeneous multiprocessor systems
Authors: Kuo Chin-Fu , Lu Yung-Feng
Published: January 2015

Currently, the multiprocessor architecture platform becomes more and more popular to the applications with higher computational capacity for meeting the fast-grown demand of applications and increasing the performance of whole system. Managing the consumption of resources has become an important issue in many different settings. The energyefficient scheduling for multiprocessors becomes one of important research issues. In this paper we study the scheduling problem of a heterogeneous non-DVSmultiprocessor platform with a task set. The processors have different characteristics of power consumption. We propose an off-line taskto- processor assignment algorithm, the
Best-Fit Decreasing Physical Power Consumption
(BDPC) algorithm to derive a feasible task assignment with the minimal energy consumption and has the time complexity of
O
(
N
(
logN
+
M
)), where
N
and
M
are the numbers of tasks and processor types, respectively. A series of experiments were conducted to evaluate the proposed algorithm. The experimental results demonstrate that the performance of the proposed BDPC algorithm is better than the compared algorithms.
Simulation-based evaluations of DAG scheduling in hard real-time multiprocessor systems
Authors: Qamhieh Manar , Midonnet Serge
Published: January 2015

The scheduling of parallel real-time tasks on multiprocessor systems is more complicated than the one of independent sequential tasks, specially for the Directed Acyclic Graph (DAG) model. The complexity is due to the structure of DAG tasks and the precedence constraints between their subtasks. The trivial DAG scheduling approach is to directly apply common real-time scheduling algorithms on DAGs despite their lack of compatibility with the parallel model. Another scheduling approach, which is called the stretching method, aims at transforming each parallel DAG task in the set into a collection of independent sequential threads that are easier to be scheduled.

In this paper, we are interested in analyzing global preemptive scheduling of DAGs using both approaches by showing that they are not comparable when associated with Deadline Monotonic (DM) and Earliest Deadline First (EDF) scheduling algorithms. Then we use extensive simulations to evaluate their schedulability performance. To this end, we use our simulation tool
YARTISS
to generate random DAG tasks with many parameter variations so as to guarantee reliable experimental results.
Constant bandwidth server revisited
Authors: Abeni Luca , Lipari Giuseppe , Lelli Juri
Published: January 2015

The Constant Bandwidth Server (CBS) is an algorithm for providing temporal protection and real-time guarantees to real-time sporadic tasks. Recently, an implementation of this algorithim called SCHED_DEADLINE has been included in the Linux kernel. Therefore, the CBS algorithm is now used to serve more generic tasks than do not obey to the classical sporadic task model. One important type of tasks which was not considered by the original CBS algorithm is the so called "self-suspending task model", where a task instance can suspend itself waiting for an external event. Even if the original algorithm is adapted so that the temporal protection property continues to hold, it is difficult for developers to provide guarantees and to select the most appropriate server parameters for such tasks. This paper investigates the problem of using the CBS algorithm for serving self-suspending tasks, by analysing it from a theoretical point of view and showing how to select the server parameters (budget and periods) for self-suspending tasks. Finally, the effectiveness of these proposals is shown through both simulations and real experiments on Linux / SCHED_DEADLINE.