bluuebunny/crossref_metadata_2025 huggingface dataset:
Randomised controlled trial of topical kanuka honey for the treatment of rosacea
Authors: Braithwaite Irene , Hunt Anna , Riley Judith , Fingleton James , Kocks Janwillem , Corin Andrew , Helm Colin , Sheahan Davitt , Tofield Christopher , Montgomery Barney , Holliday Mark , Weatherall Mark , Beasley Richard
Published: June 2015

Objective

To investigate the efficacy of topical 90% medical-grade kanuka honey and 10% glycerine (Honevo) as a treatment for rosacea.

Design

Randomised controlled trial with blinded assessment of primary outcome variable.

Setting

Outpatient primary healthcare population from 5 New Zealand sites.

Participants

138 adults aged ≥16, with a diagnosis of rosacea, and a baseline blinded Investigator Global Assessment of Rosacea Severity Score (IGA-RSS) of ≥2. 69 participants were randomised to each treatment arm. 1 participant was excluded from the Honevo group, and 7 and 15 participants withdrew from the Honevo and control groups, respectively.

Interventions

Participants were randomly allocated 1:1 to Honevo or control cream (Cetomacrogol), applied twice daily for 8 weeks.

Main outcome measures

The primary outcome measure was the proportion of participants who had a ≥2 improvement in the 7-point IGA-RSS at week 8 compared to baseline. Secondary outcomes included change in IGA-RSS and subject-rated visual analogue score of change in severity (VAS-CS) on a 100 mm scale (0 mm ‘much worse’, 100 mm ‘much improved’) at weeks 2 and 8.

Results

24/68 (34.3%) in the Honevo group and 12/69 (17.4%) in the control group had a ≥2 improvement in IGA-RSS at week 8 compared to baseline (relative risk 2.03; 95% CI 1.11 to 3.72, p=0.020). The change in IGA-RSS for Honevo compared to control at week 2 minus baseline was −1 (Hodges-Lehman estimate, 95% CI −1 to 0, p=0.03), and at week 8 minus baseline was −1 (Hodges-Lehman estimate, 95% CI −1 to 0, p=0.005). The VAS-CS at week 2 was 9.1 (95% CI 3.5 to 14.7), p=0.002, and at week 8 was 12.3 (95% CI 5.7 to 18.9)¸ p<0.001 for Honevo compared to control.

Conclusions

Honevo is an effective treatment for rosacea.

Trial registration number

This trial was registered in the Australian and New Zealand Clinical Trials Registry ACTRN12614000004662.
The chemokine receptor CXCR7 influences prognosis in human glioma in an IDH1-dependent manner
Authors: Birner Peter , Tchorbanov Andrey , Natchev Sevdalin , Tuettenberg Jochen , Guentchev Marin
Published: June 2015

Aims

The chemokine receptor CXCR7 is found on glioma cells and glioma-associated vessels and dependent upon its localisation on tumour or endothelial cells the CXCR7 receptor can mediate glioma cell invasion and tumour angiogenesis. Its expression predicts survival in several types of cancers.

Methods

We immunohistochemically studied the expression of CXCR7 and its ligand SDF1α in a cohort of 354 human patients with glioma. In an in vivo glioma model, we studied the effect of selective CXCR7 inhibition on mean vascular density.

Results

Here we show that expression of either mutant isocitrate dehydrogenase (IDH) 1 or podoplanin (PDPN), two proteins present in basically non-overlapping glioma populations, predicts the prognostic significance of CXCR7. Specifically, expression of CXCR7 on endothelial cells in IDH1 mutant cases predicted poor outcome. Surprisingly, in PDPN expressing gliomas, one of the marker genes for the recently identified mesenchymal subgroup, expression of CXCR7 predicts diminished prognosis on tumour cells and better prognosis on endothelial cells.

Conclusions

Since CXCR7 is expressed on migrating cells our data suggest that, although ubiquitously present, angiogenesis and invasion are outcome-relevant events in specific glioma subgroups, providing a potentially important tool for targeted therapy assignment.
Treatment choices in elderly patients with ST: elevation myocardial infarction—insights from the Vital Heart Response registry
Authors: Toleva Olga , Ibrahim Quazi , Brass Neil , Sookram Sunil , Welsh Robert
Published: June 2015

Background

Management of elderly patients with ST elevation myocardial infarction (STEMI) is challenging and they are under-represented in trials. Accordingly, we analysed reperfusion strategies and their effectiveness in patients with STEMI ≥75 years compared to <75 years within a comprehensive inclusive registry.

Methods

Consecutive patients with STEMI admitted to hospital and tracked within a regional registry (2006–2011) were analysed comparing reperfusion strategy (primary percutaneous coronary intervention (PPCI), fibrinolysis and no reperfusion) between patients ≥75 vs <75 years old as well as across the reperfusion strategies in those ≥75 years.

Results

There were 3588 patients with STEMI with 646 (18%) ≥75 years old. Elderly patients were more likely female (46.9% vs 18.4%) and had more prior: angina (28.2% vs 17.2%), myocardial infarction (MI; 22.8% vs 13.9%), hypertension (67.6% vs 44.2%), heart failure (2.3% vs 0.3%) and atrial fibrillation (2.2% vs 0.5%) (all p<0.001). The reperfusion strategy for patients ≥75 vs <75: PPCI 45.3% vs 41.2%, fibrinolysis 24.8% vs 45.7%, and no reperfusion 29.9% vs 13.1% (p<0.001). Time from symptoms to first medical contact (median, 93 vs 78 min p=0.008) and PPCI (median, 166 vs 136 min (p<0.001) were longer for ≥75 years. In those ≥75 years outcomes by reperfusion (PPCI, fibrinolysis and none) were: in-hospital death 13.3%, 9.4% and 19.7% (p=0.018), and composite of death, recurrent-MI, cardiogenic shock and congestive heart failure 28%, 20% and 33.2% (p=0.022).

Conclusions

Elderly patients have more comorbidities, worst in-hospital clinical outcomes and are less likely to receive reperfusion. Acknowledging physician selection of the reperfusion strategy; outcomes appear favourable in the elderly receiving fibrinolysis.
A preliminary investigation into the moral reasoning abilities of UK veterinarians
Authors: Batchelor C. E. M. , Creed A. , McKeegan D. E. F.
Published: June 2015

Veterinary medicine is an ethically challenging profession, but the ethical reasoning abilities of practising veterinarians in the UK have never been formally assessed. This study investigated moral reasoning ability in 65 qualified veterinarians (38 practising and 27 academic) and 33 members of the public in the UK using the Defining Issues Test. Academic veterinarians had higher scores than members of the public but practising veterinarians did not. There was large variation in moral reasoning abilities among qualified veterinarians. Moral reasoning score in veterinarians did not improve with years of experience. These results show that despite having a professional degree moral reasoning skills of practising veterinarians may be insufficient to deal with the demands of their profession. This could have implications for animal welfare, client services and veterinarian wellbeing. The results highlight the need for more training in this area.
Maintaining the high diversity of pine and oak species in Mexican temperate forests: a new management approach combining functional zoning and ecosystem adaptability
Authors: Galicia Leopoldo , Potvin Catherine , Messier Christian
Published: June 2015

Mexican temperate forests, at the southernmost end of the distribution range of this ecosystem, are the world’s centre of diversity of pine and oak, with 55 and 161 species, respectively. Such forests are threatened by land-use change, unsustainable forest management practices, and climate change; these threats reduce their diversity, alter the distribution ranges of species, modify disturbance regimes, and reduce ecosystem adaptability. This paper briefly reviews (i) the ecology of the Mexican temperate forests, (ii) the ecological basis for the unique diversity of pine and oak species, (iii) the main disturbances as well as the main drivers of global changes affecting these forests, in particular climate change, and (iv) the social, economic, and cultural factors to be considered in proposing a new forest management approach. It proposes a new conceptual framework to manage Mexican temperate forests that are in line with (i) their natural dynamics, (ii) the rapidly changing and uncertain global environmental, social, and economic conditions, and (iii) the complex adaptive system approach. This new forest management combines functional zoning, multispecies plantations, and sylvicultural interventions to increase the adaptive capacity of forests as a way to balance the increasing need for timber products with the need for other ecosystem services facing rapidly changing and uncertain future environmental, social, and economic conditions.
An Established Cell Line from the Atlantic Salmon (Salmo salar)
Authors: Nicholson Bruce L. , Byrne Charles
Published: June 2015

A monolayer culture of fibroblast-like cells was initiated from a trypsin digest of heart, liver, kidney, and spleen tissue of young Atlantic salmon (Salmo salar). This culture has been subcultured 81 times over a period of 21 months and appears to be an established cell line, which we have designated AS. Cells of the AS line multiply over a temperature range of 4–28 C with an optimum growth temperature of 20 C. Temperatures in excess of 29 C cause rapid cell death. The AS cells remain viable for periods up to 6 months at 4 C. An absolute plating efficiency of 30% has been determined for AS cells at 20 C. Analysis of the cell cycle of AS cells reveals a generation time (Gt) of 19.5 hr. The duration of the DNA synthetic period (S) is 10.5 hr, while the G1 and G2 periods are 1.1 and 7.1 hr, respectively. The duration of mitosis (M) has been calculated to be 0.9 hr with a mitotic index (M.I.) for the culture of 3.3%. Preliminary studies indicate a modal chromosome number of 54. The AS cell line is susceptible to infectious pancreatic necrosis (IPN) virus, infectious hematopoietic necrosis (IHN) virus and the myxovirus of bluegills.
Effects of Brief Temperature Increases on Larvae of the American Oyster (Crassostrea virginica)
Authors: Diaz Robert J.
Published: June 2015

Growth of larvae of the American oyster (Crassostrea virginica) was not affected by brief temperature increases of 10 or 15 degrees C, but a 20 degree increase had a detrimental effect. Mortality increased significantly following all temperature increases. Setting rates of larvae receiving 15 or 20 degree increases were significantly lower. Growth rate, mortality, and setting also seemed to be affected by the age at which larvae received a thermal shock.
Homing of Brook Trout (Salvelinus fontinalis) in Matamek Lake, Quebec
Authors: O’Connor J. F. , Power G.
Published: June 2015

Brook trout (Salvelinus fontinalis) showed both in-season and repeat homing to spawning tributaries of Matamek Lake, Quebec. Of 283 trout clipped from Gallienne Creek and Kaikhosru Creek during August and September, 1971, 31.1% returned to the homestreams to spawn in 1972. During July and August, 1972, 450 trout were tagged and displaced from these two streams and released at three points (0.20–4.50 km) in the lake. Of these fish, 44.0% homed, 0.2% strayed to the opposite stream and the remainder were unaccounted for. Percentage returns from the deepwater release point was much lower than returns from the two inshore release points, and average return time was proportional to the distance from the homestream.
Discharge of Nitrilotriacetate (NTA) from Two Sewage Treatment Facilities Located in a Midcontinental Climate
Authors: Rudd John W. M. , Townsend B. E. , Hamilton R. D.
Published: June 2015

Concentrations of NTA entering the Red and Assiniboine rivers from two Winnipeg sewage treatment facilities were monitored. The activated sludge plant usually discharged < 0.5-mg NTA/liter throughout the year. The aerated sewage lagoon discharged < 20μg NTA/liter during summer. It was believed that the NTA passed through the lagoon essentially unchanged during winter (1800-μg NTA/liter) when degradation rates must have been extremely low. No NTA was detected in river water downstream from either of these facilities. It was concluded that even under extreme environmental conditions NTA discharge did not present a hazard to either local aquifers or the local biota.
Validating variational principle for higher order theory of gravity
Authors: Ruz Soumendranath , Sarkar Kaushik , Sk Nayem , Sanyal Abhik Kumar
Published: June 2015

Metric variation of higher order theory of gravity requires fixing of the Ricci scalar in addition to the metric tensor at the boundary. Fixing Ricci scalar at the boundary implies that the classical solutions are fixed once and forever to the de Sitter or anti-de Sitter (dS/AdS) solutions. Here, we justify such requirement from the standpoint of Noether symmetry.
BoostFS: A Boosting-Based Irrelevant Feature Selection Algorithm
Authors: Miao Qi-Guang , Cao Ying , Song Jian-Feng , Liu Jiachen , Quan Yining
Published: June 2015

In a learning process, features play a fundamental role. In this paper, we propose a Boosting-based feature selection algorithm called BoostFS. It extends AdaBoost which is designed for classification problems to feature selection. BoostFS maintains a distribution over training samples which is initialized from the uniform distribution. In each iteration, a decision stump is trained under the sample distribution and then the sample distribution is adjusted so that it is orthogonal to the classification results of all the generated stumps. Because a decision stump can also be regarded as one selected feature, BoostFS is capable to select a subset of features that are irrelevant to each other as much as possible. Experimental results on synthetic datasets, five UCI datasets and a real malware detection dataset all show that the features selected by BoostFS help to improve learning algorithms in classification problems, especially when the original feature set contains redundant features.
On Moufang loops that are abelian groups over the nucleus
Authors: Csörgő Piroska , Giuliani Maria L. Merlini
Published: June 2015

We give some necessary and sufficient conditions for the equivalency of the following two properties for a Moufang loop Q: Q over the nucleus Q/N is an abelian group and Q over the center is a group. We study those properties of Moufang loops which guarantee that L(y, x) is in the automorphism group of the loop. These imply numerous statements, among them there are well-known old results.
ALE–VMS formulation for stratified turbulent incompressible flows with applications
Authors: Bazilevs Y. , Korobenko A. , Yan J. , Pal A. , Gohari S. M. I. , Sarkar S.
Published: June 2015

A numerical formulation for incompressible flows with stable stratification is developed using the framework of variational multiscale methods. In the proposed formulation, both density and temperature stratification are handled in a unified manner. The formulation is augmented with weakly-enforced essential boundary conditions and is suitable for applications involving moving domains, such as fluid–structure interaction. The methodology is tested using three numerical examples ranging from flow-physics benchmarks to a simulation of a full-scale offshore wind-turbine rotor spinning inside an atmospheric boundary layer. Good agreement is achieved with experimental and computational results reported by other researchers. The wind-turbine rotor simulation shows that flow stratification has a strong influence on the dynamic rotor thrust and torque loads.
Automating unambiguous NOE data usage in NVR for NMR protein structure-based assignments
Authors: Akhmedov Murodzhon , Çatay Bülent , Apaydın Mehmet Serkan
Published: June 2015

Nuclear Magnetic Resonance (NMR) Spectroscopy is an important technique that allows determining protein structure in solution. An important problem in protein structure determination using NMR spectroscopy is the mapping of peaks to corresponding amino acids, also known as the assignment problem. Structure-Based Assignment (SBA) is an approach to solve this problem using a template structure that is homologous to the target. Our previously developed approach Nuclear Vector Replacement-Binary Integer Programming (NVR-BIP) computed the optimal solution for small proteins, but was unable to solve the assignments of large proteins. NVR-Ant Colony Optimization (ACO) extended the applicability of the NVR approach for such proteins. One of the input data utilized in these approaches is the Nuclear Overhauser Effect (NOE) data. NOE is an interaction observed between two protons if the protons are located close in space. These protons could be amide protons, protons attached to the alpha-carbon atom in the backbone of the protein, or side chain protons. NVR only uses backbone protons. In this paper, we reformulate the NVR-BIP model to distinguish the type of proton in NOE data and use the corresponding proton coordinates in the extended formulation. In addition, the threshold value over interproton distances is set in a standard manner for all proteins by extracting the NOE upper bound distance information from the data. We also convert NOE intensities into distance thresholds. Our new approach thus handles the NOE data correctly and without manually determined parameters. We accordingly adapt NVR-ACO solution methodology to these changes. Computational results show that our approaches obtain optimal solutions for small proteins. For the large proteins our ant colony optimization-based approach obtains promising results.
Probabilistic Self-Organizing Map for Clustering and Visualizing non-i.i.d Data
Authors: Lebbah Mustapha , Jaziri Rakia , Bennani Younès , Chenot Jean-Hugues
Published: June 2015

We present a generative approach to train a new probabilistic self-organizing map (PrSOMS) for dependent and nonidentically distributed data sets. Our model defines a low-dimensional manifold allowing friendly visualizations. To yield the topology preserving maps, our model has the SOM like learning behavior with the advantages of probabilistic models. This new paradigm uses hidden Markov models (HMM) formalism and introduces relationships between the states. This allows us to take advantage of all the known classical views associated to topographic map. The objective function optimization has a clear interpretation, which allows us to propose expectation-maximization (EM) algorithm, based on the forward–backward algorithm, to train the model. We demonstrate our approach on two data sets: The real-world data issued from the "French National Audiovisual Institute" and handwriting data captured using a WACOM tablet.
Analysis of Reversed Torsion of FCC Metals Using Polycrystal Plasticity Models
Authors: Guo X. Q. , Wang H. , Wu P. D. , Mao X. B.
Published: June 2015

Large strain behavior of FCC polycrystals during reversed torsion are investigated through the special purpose finite element based on the classical Taylor model and the elastic-viscoplastic self-consistent (EVPSC) model with various Self-Consistent Schemes (SCSs). It is found that the response of both the fixed-end and free-end torsion is very sensitive to the constitutive models. The models are assessed through comparing their predictions to the corresponding experiments in terms of the stress and strain curves, the Swift effect and texture evolution. It is demonstrated that none of the models examined can precisely predict all the experimental results. However, more careful observation reveals that, among the models considered, the tangent model gives the worst overall performance. It is also demonstrated that the intensity of residual texture during reverse twisting is dependent on the amounts of pre-shear strain during forward twisting and the model used.
Dynamic Analysis of Dry Frictional Disc Brake System Based on the Rigid-Flexible Coupled Model
Authors: Zhao Yini , Ding Qian
Published: June 2015

A rigid-flexible coupled dynamic model is established to investigate the dynamic behaviors of a disc brake system. The analytical model of the pad includes transverse and circumferential displacements. The disc is modeled using the thin plate theory. A governing equation of the motion of the disc is established. Then the first-order vibration equation is obtained using Galerkin method, considering only the transverse displacement. The friction between the pad and disk among the contacting area is estimated using an exponential model, in which the Stribeck effect is included. Numerical method is applied to reveal the influences of coupling dynamical relationships between the pad and disc on the whole system. The results show that with the variation of disc annular speed, the pad keeps vibrating with small amplitude due to the sustaining variation of the contacting pressure and friction. Stick-slip flutter happens as the velocity is lower than a critical speed and strong movement coupling between elements of the system brings earlier occurrence of the frictional flutter. Besides, for strong movement coupling case, before the critical speed, there are intermittent frequency ranges among which the amplitude is quite higher, which is due to a redistribution of friction and contacting pressure.
The effect of vaccination to dendritic cell and immune cell interaction in HIV disease progression
Authors: Roy Priti Kumar , Chatterjee Amar Nath , Li Xue-Zhi
Published: June 2015

In this research paper, our main objective is to find out the meticulous role of activated dendritic cells (DCs) during the human immunodeficiency virus (HIV) infection process. DCs play a dual role by enhancing both HIV infection progression, as well as antiviral immune response. To explore the implications of these dual roles, we have formulated our mathematical model and analyzed the model by both analytical and numerical approaches. By using an impulsive differential equation, we have studied the effect of DC-based vaccination. Analytically we have determined the threshold value of drug dosage and dosing interval for optimum levels of infection. We have also investigated the effect of perfect adherence of drug dose on the immune cell count in extreme cases and observed that, systematic drug dose of the immune cells leads to its maximum level.
Display Advertising Auctions with Arbitrage
Authors: Cavallo Ruggiero , Mcafee R. Preston , Vassilvitskii Sergei
Published: June 2015

Online display advertising exchanges connect Web publishers with advertisers seeking to place ads. In many cases, the advertiser obtains value from an ad impression (a viewing by a user) only if it is clicked, and frequently advertisers prefer to pay contingent on this occurring. But at the same time, many publishers demand payment independent of clicks. Arbitragers with good estimates of click-probabilities can resolve this conflict by absorbing the risk and acting as an intermediary, paying the publisher on allocation and being paid only if a click occurs. This article examines the incentives of advertisers and arbitragers and contributes an efficient mechanism with truthful bidding by the advertisers and truthful reporting of click predictions by arbitragers as dominant strategies while, given that a hazard rate condition is satisfied, yielding increased revenue to the publisher. We provide empirical evidence based on bid data from Yahoo's Right Media Exchange suggesting that the mechanism would increase revenue in practice.
Passwords and the evolution of imperfect authentication
Authors: Bonneau Joseph , Herley Cormac , van Oorschot Paul C. , Stajano Frank
Published: June 2015

Theory on passwords has lagged practice, where large providers use back-end smarts to survive with imperfect technology.
System-Level Observation Framework for Non-Intrusive Runtime Monitoring of Embedded Systems
Authors: Lee Jong Chul , Lysecky Roman
Published: June 2015

As the complexity of embedded systems rapidly increases, the use of traditional analysis and debug methods encounters significant challenges in monitoring, analyzing, and debugging the complex interactions of various software and hardware components. This situation is further exacerbated for in-situ debugging and verification in which traditional debug and trace interfaces that require physical access are unavailable, infeasible, or cost prohibitive. In this article, we present a system-level observation framework that provides minimally intrusive methods for dynamically monitoring and analyzing deeply integrated hardware and software components within embedded systems. The system-level observation framework monitors hardware and software events by inserting additional logic for detecting designer-specified events within hardware cores to observe complex interaction across hardware and software boundaries at runtime, and provides visibility for monitoring complex execution behavior of software applications without affecting the system execution.
Report on RecSys 2014
Authors: Bogers Toine , Koolen Marijn , Cantador Iván
Published: June 2015

While content-based recommendation has been applied successfully in many different domains, it has not seen the same level of attention as collaborative filtering techniques have. However, there are many recommendation domains and applications where content and metadata play a key role, either in addition to or instead of ratings and implicit usage data. For some domains, such as movies, the relationship between content and usage data has seen thorough investigation already, but for many other domains, such as books, news, scientific articles, andWeb pages we still do not know if and how these data sources should be combined to provided the best recommendation performance. The CBRecSys 2014 workshop aimed to address this by providing a dedicated venue for papers dedicated to all aspects of content-based recommender systems.
Report on the First Workshop on Supporting Complex Search Tasks
Authors: Gäde Maria , Hall Mark M. , Huurdeman Hugo , Kamps Jaap , Koolen Marijn , Skove Mette , Toms Elaine , Walsh David
Published: June 2015

There is broad consensus in the field of IR that search is complex in many use cases and applications, both on theWeb and in domain specific collections, and both in our professional and in our daily life. Yet our understanding of complex search tasks, in comparison to simple look up tasks, is fragmented at best. The workshop addressed many open research questions: What are the obvious use cases and applications of complex search? What are essential features of work tasks and search tasks to take into account? And how do these evolve over time? With a multitude of information, varying from introductory to specialized, and from authoritative to speculative or opinionated, when to show what sources of information? How does the information seeking process evolve and what are relevant differences between different stages? With complex task and search process management, blending searching, browsing, and recommendations, and supporting exploratory search to sensemaking and analytics, UI and UX design pose an overconstrained challenge. How do we know that our approach is any good? Supporting complex search tasks requires new collaborations across the whole field of IR, and the proposed workshop brought together a diverse group of researchers to work together on one of the greatest challenges of our field.

The workshop featured three main elements. First, a keynote on an emerging theory of task difficulty by Diane Kelly. Second, a lively boaster and poster session in which seven contributed papers were presented. Third, three breakout groups on: 1) user interfaces and user experience, 2) tasks and users, and 3) information needs on controversial topics. There was an general feeling that the discussion made progress, and built new connections between related strands of research in IR.
Power of
d
Choices for Large-Scale Bin Packing
Authors: Xie Qiaomin , Dong Xiaobo , Lu Yi , Srikant Rayadurgam
Published: June 2015

We consider a system of $N$ parallel servers, where each server consists of
B
units of a resource. Jobs arrive at this system according to a Poisson process, and each job stays in the system for an exponentially distributed amount of time. Each job may request different units of the resource from the system. The goal is to understand how to route arriving jobs to the servers to minimize the probability that an arriving job does not find the required amount of resource at the server, i.e., the goal is to minimize blocking probability. The motivation for this problem arises from the design of cloud computing systems in which the jobs are virtual machines (VMs) that request resources such as memory from a large pool of servers. In this paper, we consider power-of-
d
-choices routing, where a job is routed to the server with the largest amount of available resource among
d
≥ 2 randomly chosen servers. We consider a fluid model that corresponds to the limit as
N
goes to infinity and provide an explicit upper bound for the equilibrium blocking probability. We show that the upper bound exhibits different behavior as
B
goes to infinity depending on the relationship between the total traffic intensity λ and
B
. In particular, if (
B
-- λ)/√λ → α, the upper bound is doubly exponential in √λ and if (
B
-- λ)/log
d
λ → β, β > 1, the upper bound is exponential in λ. Simulation results show that the blocking probability, even for small
B
, exhibits qualitatively different behavior in the two traffic regimes. This is in contrast with the result for random routing, where the blocking probability scales as
O
(1/√λ) even if (
B
-- λ)/√λ → α.
Whittle Index Approach to Size-aware Scheduling with Time-varying Channels
Authors: Aalto Samuli , Lassila Pasi , Osti Prajwal
Published: June 2015

We consider the optimal opportunistic scheduling problem for downlink data traffic in a wireless cell with time-varying channels. The scheduler itself operates in a very fast timescale of milliseconds, but the objective function is related to minimizing the holding costs in a much longer timescale, at the so-called flow level. The Whittle index approach is a powerful tool in this context, since it renders the flow level optimization problem with heterogeneous users tractable. Until now, this approach has been applied to the opportunistic scheduling problem to generate non-anticipating index policies that may depend on the amount of attained service but do not utilize the exact size information. In this paper, we produce a size-aware (i.e., anticipating) index policy by applying the Whittle index approach in a novel way. By a numerical study based on simulations, we demonstrate that the resulting size-aware index policy systematically improves performance. As a side result, we show that the opportunistic scheduling problem is indexable when the file sizes follow the Pascal distribution, and we derive the corresponding Whittle index, which generalizes earlier results.
60 GHz Indoor Networking through Flexible Beams
Authors: Sur Sanjib , Venkateswaran Vignesh , Zhang Xinyu , Ramanathan Parmesh
Published: June 2015

60 GHz technology holds tremendous potential to upgrade wireless link throughput to Gbps level. To overcome inherent vulnerability to attenuation, 60 GHz radios communicate by forming highly-directional electronically-steerable beams. Standards like IEEE 802.11ad have tailored MAC/PHY protocols to such flexible-beam 60 GHz networks. However, lack of a reconfigurable platform has thwarted a realistic proof-of-concept evaluation. In this paper, we conduct an in-depth measurement of indoor 60 GHz networks using a first-of-its-kind software-radio platform. Our measurement focuses on the link-level behavior with three major perspectives: (i) coverage and bit-rate of a single link, and implications for 60 GHz MIMO; (ii) impact of beam-steering on network performance, particularly under human blockage and device mobility; (iii) spatial reuse between flexible beams. Our study dispels some common myths, and reveals key challenges in maintaining robust flexible-beam connection. We propose new principles that can tackle such challenges based on unique properties of 60 GHz channel and cognitive capability of 60 GHz links.
Spy vs. Spy
Authors: Fanti Giulia , Kairouz Peter , Oh Sewoong , Viswanath Pramod
Published: June 2015

Anonymous messaging platforms, such as Secret, Yik Yak and Whisper, have emerged as important social media for sharing one's thoughts without the fear of being judged by friends, family, or the public. Further, such anonymous platforms are crucial in nations with authoritarian governments; the right to free expression and sometimes the personal safety of the author of the message depend on anonymity. Whether for fear of judgment or personal endangerment, it is crucial to keep anonymous the identity of the user who initially posted a sensitive message. In this paper, we consider an adversary who observes a snapshot of the spread of a message at a certain time. Recent advances in rumor source detection shows that the existing messaging protocols are vulnerable against such an adversary. We introduce a novel messaging protocol, which we call adaptive diffusion, and show that it spreads the messages fast and achieves a perfect obfuscation of the source when the underlying contact network is an infinite regular tree: all users with the message are nearly equally likely to have been the origin of the message. Experiments on a sampled Facebook network show that it effectively hides the location of the source even when the graph is finite, irregular and has cycles.
Reducing Latency via Redundant Requests
Authors: Gardner Kristen , Zbarsky Samuel , Doroudi Sherwin , Harchol-Balter Mor , Hyytia Esa
Published: June 2015

Recent computer systems research has proposed using redundant requests to reduce latency. The idea is to run a request on multiple servers and wait for the first completion (discarding all remaining copies of the request). However there is no exact analysis of systems with redundancy.

This paper presents the first exact analysis of systems with redundancy. We allow for any number of classes of redundant requests, any number of classes of non-redundant requests, any degree of redundancy, and any number of heterogeneous servers. In all cases we derive the limiting distribution on the state of the system.

In small (two or three server) systems, we derive simple forms for the distribution of response time of both the redundant classes and non-redundant classes, and we quantify the "gain" to redundant classes and "pain" to non-redundant classes caused by redundancy. We find some surprising results. First, the response time of a fully redundant class follows a simple Exponential distribution and that of the non-redundant class follows a Generalized Hyperexponential. Second, fully redundant classes are "immune" to any pain caused by other classes becoming redundant.

We also compare redundancy with other approaches for reducing latency, such as optimal probabilistic splitting of a class among servers (Opt-Split) and Join-the-Shortest-Queue (JSQ) routing of a class. We find that, in many cases, redundancy outperforms JSQ and Opt-Split with respect to overall response time, making it an attractive solution.
Latency in Software Defined Networks
Authors: He Keqiang , Khalid Junaid , Das Sourav , Gember-Jacobson Aaron , Prakash Chaithan , Akella Aditya , Li Li Erran , Thottan Marina
Published: June 2015

We conduct a comprehensive measurement study of switch control plane latencies using four types of production SDN switches. Our measurements show that control actions, such as rule installation, have surprisingly high latency, due to both software implementation inefficiencies and fundamental traits of switch hardware. We also propose three measurement-driven latency mitigation techniques---optimizing route selection, spreading rules across switches, and reordering rule installations---to effectively tame the flow setup latencies in SDN.
Scheduling Storms and Streams in the Cloud
Authors: Ghaderi Javad , Shakkottai Sanjay , Srikant Rayadurgam
Published: June 2015

Motivated by emerging big
streaming data
processing paradigms (e.g., Twitter Storm, Streaming MapReduce), we investigate the problem of scheduling graphs over a large cluster of servers. Each graph is a job, where nodes represent compute tasks and edges indicate data-flows between these compute tasks. Jobs (graphs) arrive randomly over time, and upon completion, leave the system. When a job arrives, the scheduler needs to partition the graph and distribute it over the servers to satisfy load balancing and cost considerations. Specifically, neighboring compute tasks in the graph that are mapped to different servers incur load on the network; thus a mapping of the jobs among the servers incurs a cost that is proportional to the number of "broken edges''. We propose a low complexity randomized scheduling algorithm that, without service preemptions, stabilizes the system with graph arrivals/departures; more importantly, it allows a smooth trade-off between minimizing average partitioning cost and average queue lengths. Interestingly, to avoid service preemptions, our approach does not rely on a Gibbs sampler; instead, we show that the corresponding limiting invariant measure has an interpretation stemming from a loss system.
Pricing Bilateral Electricity Trade between Smart Grids and Hybrid Green Datacenters
Authors: Zhou Zhi , Liu Fangming , Li Zongpeng
Published: June 2015

Datacenter demand response is envisioned as a promising approach for mitigating operational instability faced by smart grids. It enables significant potentials in peak load shedding and facilitates the incorporation of distributed generation and intermittent energy sources. This work considers two key aspects towards realtime electricity pricing for eliciting demand response: (i) Two-way electricity flow between smart grids and large datacenters with hybrid green generation capabilities. (ii) The geo-distributed nature of large cloud systems, and hence the potential competition among smart grids that serve different datacenters of the cloud. We propose a pricing scheme tailored for geo-distributed green datacenters, from a multi-leader single-follower game point of view. At the cloud side, in quest for performance, scalability and robustness, the energy cost is minimized in a distributed manner, based on the technique of alternating direction of multipliers (ADMM). At the smart grid side, a practical equilibrium of the pricing game is desired. To this end, we employ mathematical programming with equilibrium constraints (MPEC), equilibrium problem with equilibrium constraints (EPEC) and exact linearization, to transform the multi-leader single-follower pricing game into a mixed integer linear program (MILP) that can be readily solved. The effectiveness of the proposed solutions is evaluated based on trace-driven simulations.
Expression of rat Na-K-ATPase α2 enables ion pumping but not ouabain-induced signaling in α1-deficient porcine renal epithelial cells
Authors: Xie Joe , Ye Qiqi , Cui Xiaoyu , Madan Namrata , Yi Qiying , Pierre Sandrine V. , Xie Zijian
Published: June 2015

Na-K-ATPase is a fundamental component of ion transport. Four α isoforms of the Na-K-ATPase catalytic α subunit are expressed in human cells. The ubiquitous Na-K-ATPase α1 was recently discovered to also mediate signal transduction through Src kinase. In contrast, α2 expression is limited to a few cell types including myocytes, where it is coupled to the Na+/Ca2+ exchanger. To test whether rat Na-K-ATPase α2 is capable of cellular signaling like its α1 counterpart in a recipient mammalian system, we used an α1 knockdown pig renal epithelial cell (PY-17) to create an α2-expressing cell line with no detectable level of α1 expression. These cells exhibited normal ouabain-sensitive ATPase, but failed to effectively regulate Src. In contrast to α1-expressing cells, ouabain did not stimulate Src kinase or downstream effectors such as ERK and Akt in α2 cells, although their signaling apparatus was intact as evidenced by EGF-mediated signal transduction. Additionally, α2 cells were unable to rescue caveolin-1. Unlike the NaKtide sequence derived from Na-K-ATPase α1, which downregulates basal Src activity, the corresponding α2 NaKtide was unable to inhibit Src in vitro. Finally, coimmunoprecipitation of cellular Src was diminished in α2 cells. These findings indicate that Na-K-ATPase α2 does not regulate Src and, therefore, may not serve the same role in signal transduction as α1. This further implies that the signaling mechanism of Na-K-ATPase is isoform specific, thereby supporting a model where α1 and α2 isoforms play distinct roles in mediating contraction and signaling in myocytes.
A high-throughput assay for quantifying appetite and digestive dynamics
Authors: Jordi Josua , Guggiana-Nilo Drago , Soucy Edward , Song Erin Yue , Lei Wee Caroline , Engert Florian
Published: June 2015

Food intake and digestion are vital functions, and their dysregulation is fundamental for many human diseases. Current methods do not support their dynamic quantification on large scales in unrestrained vertebrates. Here, we combine an infrared macroscope with fluorescently labeled food to quantify feeding behavior and intestinal nutrient metabolism with high temporal resolution, sensitivity, and throughput in naturally behaving zebrafish larvae. Using this method and rate-based modeling, we demonstrate that zebrafish larvae match nutrient intake to their bodily demand and that larvae adjust their digestion rate, according to the ingested meal size. Such adaptive feedback mechanisms make this model system amenable to identify potential chemical modulators. As proof of concept, we demonstrate that nicotine, l-lysine, ghrelin, and insulin have analogous impact on food intake as in mammals. Consequently, the method presented here will promote large-scale translational research of food intake and digestive function in a naturally behaving vertebrate.
Offline reactivation of experience-dependent neuronal firing patterns in the rat ventral tegmental area
Authors: Valdés José L. , McNaughton Bruce L. , Fellous Jean-Marc
Published: June 2015

In a rest period immediately after a task, neurons in the hippocampus, neocortex, and striatum exhibit spatiotemporal correlation patterns resembling those observed during the task. This reactivation has been proposed as a neurophysiological substrate for memory consolidation. We provide new evidence that rodent ventral tegmental area (VTA) neurons are selective for different types of food stimuli and that stimulus-sensitive neurons strongly reactivate during the rest period following a task that involved those stimuli. Reactivation occurred primarily during slow wave sleep and during quiet awakeness. In these experiments, VTA reactivation patterns were uncompressed and occurred at the firing rate level, rather than on a spike-to-spike basis. Mildly aversive stimuli were reactivated more often than positive ones. The VTA is a pivotal structure involved in the perception and prediction of reward and stimulus salience and is a key neuromodulatory system involved in synaptic plasticity. These results suggest new ways in which dopaminergic signals could contribute to the biophysical mechanisms of selective, system-wide, memory consolidation, and reconsolidation during sleep.
An arterially perfused nose-olfactory bulb preparation of the rat
Authors: Pérez de los Cobos Pallarés Fernando , Stanić Davor , Farmer David , Dutschmann Mathias , Egger Veronica
Published: June 2015

A main feature of the mammalian olfactory bulb network is the presence of various rhythmic activities, in particular, gamma, beta, and theta oscillations, with the latter coupled to the respiratory rhythm. Interactions between those oscillations as well as the spatial distribution of network activation are likely to determine olfactory coding. Here, we describe a novel semi-intact perfused nose-olfactory bulb-brain stem preparation in rats with both a preserved olfactory epithelium and brain stem, which could be particularly suitable for the study of oscillatory activity and spatial odor mapping within the olfactory bulb, in particular, in hitherto inaccessible locations. In the perfused olfactory bulb, we observed robust spontaneous oscillations, mostly in the theta range. Odor application resulted in an increase in oscillatory power in higher frequency ranges, stimulus-locked local field potentials, and excitation or inhibition of individual bulbar neurons, similar to odor responses reported from in vivo recordings. Thus our method constitutes the first viable in situ preparation of a mammalian system that uses airborne odor stimuli and preserves these characteristic features of odor processing. This preparation will allow the use of highly invasive experimental procedures and the application of techniques such as patch-clamp recording, high-resolution imaging, and optogenetics within the entire olfactory bulb.
Neuronal Reward and Decision Signals: From Theories to Data
Authors: Schultz Wolfram
Published: June 2015

Rewards are crucial objects that induce learning, approach behavior, choices, and emotions. Whereas emotions are difficult to investigate in animals, the learning function is mediated by neuronal reward prediction error signals which implement basic constructs of reinforcement learning theory. These signals are found in dopamine neurons, which emit a global reward signal to striatum and frontal cortex, and in specific neurons in striatum, amygdala, and frontal cortex projecting to select neuronal populations. The approach and choice functions involve subjective value, which is objectively assessed by behavioral choices eliciting internal, subjective reward preferences. Utility is the formal mathematical characterization of subjective value and a prime decision variable in economic choice theory. It is coded as utility prediction error by phasic dopamine responses. Utility can incorporate various influences, including risk, delay, effort, and social interaction. Appropriate for formal decision mechanisms, rewards are coded as object value, action value, difference value, and chosen value by specific neurons. Although all reward, reinforcement, and decision variables are theoretical constructs, their neuronal signals constitute measurable physical implementations and as such confirm the validity of these concepts. The neuronal reward signals provide guidance for behavior while constraining the free will to act.
Network Utilization Improvement via a Predictive Load Scheduling Scheme in Heterogeneous Wireless Networks
Authors: Fang Bin , Zhou Wuyang
Published: June 2015

In heterogeneous wireless networks (HWNs), the large-coverage cellular networks are usually overlaid with denser small-coverage microcells, wireless local area networks (WLANs), femtocells, and even relays. To prevent unbalanced load distribution in these HWNs from decreasing network utilization and degrading the quality of service (QoS), load scheduling between the overlaid networks is essential and should be reasonably designed. In fact, unbalanced load distribution can be directly reflected by the idle durations of networks and channels. In this paper, a predictive load scheduling scheme is proposed from the point of decreasing the capacity-weighted idle durations of networks and channels. For the proposed scheme, a fairly general HWNs scenario is considered, the scheduling problem is formulated, an iteration-based predictive method is given to obtain the idle duration, and a gradient descent method is derived for the optimal scheduled load. In the simulation, the effectiveness of the idle duration prediction method is validated, and the simulation results show that the proposed load scheduling scheme can greatly improve the network utilization and QoS.