bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Gonadotrophins on the Respiration of Isolated Cells from the Prepubertal Rat Ovary
Authors: Hamberger Lars A.
Published: July 2014

A detailed description for separation by microdissection of various types of cells from prepubertal rat ovaries is reported. The rate of oxidation of succinate under influence of gonadotrophins was measured in the various cell samples applying the micro‐diver technique (Zeuthen 1953). The dry weight of the cell samples was determined by a direct x‐ray absorption technique (Rosengren 1959). The gonadotrophins were injected to the animals either 2 hrs before removal of the ovaries, or added directly to the incubation medium. In isolated granulosa cells the rate of oxygen uptake was significantly enhanced by LH administered in vitro or in vivo, while FSH had no stimulatory effects. The theca cells showed the opposite pattern i.e. a stimulatory effect on the rate of oxygen uptake by FSH both in vitro and in vivo, but no stimulatory effect by LH. The oxygen uptake of interstitial cells was clearly stimulated by FSH in vivo and probably also by in vitro administration of this hormone. LH showed no tendency to increase the rate of oxygen uptake by these cells. The results support the theory that FSH and LH selectively stimulate various types of ovarian cells.
HPV vaccine stimulates cytotoxic activity of killer dendritic cells and natural killer cells against HPV‐positive tumour cells
Authors: Van den Bergh Johan M. J. , Guerti Khadija , Willemen Yannick , Lion Eva , Cools Nathalie , Goossens Herman , Vorsters Alex , Van Tendeloo Viggo F. I. , Anguille Sébastien , Van Damme Pierre , Smits Evelien L. J. M.
Published: July 2014

Cervarix™ is approved as a preventive vaccine against infection with the human papillomavirus (HPV) strains 16 and 18, which are causally related to the development of cervical cancer. We are the first to investigate in vitro the effects of this HPV vaccine on interleukin (IL)‐15 dendritic cells (DC) as proxy of a naturally occurring subset of blood DC, and natural killer (NK) cells, two innate immune cell types that play an important role in antitumour immunity. Our results show that exposure of IL‐15 DC to the HPV vaccine results in increased expression of phenotypic maturation markers, pro‐inflammatory cytokine production and cytotoxic activity against HPV‐positive tumour cells. These effects are mediated by the vaccine adjuvant, partly through Toll‐like receptor 4 activation. Next, we demonstrate that vaccine‐exposed IL‐15 DC in turn induce phenotypic activation of NK cells, resulting in a synergistic cytotoxic action against HPV‐infected tumour cells. Our study thus identifies a novel mode of action of the HPV vaccine in boosting innate immunity, including killing of HPV‐infected cells by DC and NK cells.
Global biogeography of the ectomycorrhizal /sebacina lineage (Fungi, Sebacinales) as revealed from comparative phylogenetic analyses
Authors: Tedersoo Leho , Bahram Mohammad , Ryberg Martin , Otsing Eveli , Kõljalg Urmas , Abarenkov Kessy
Published: July 2014

Compared with plants and animals, large‐scale biogeographic patterns of microbes including fungi are poorly understood. By the use of a comparative phylogenetic approach and ancestral state reconstructions, we addressed the global biogeography, rate of evolution and evolutionary origin of the widely distributed ectomycorrhizal (EcM) /sebacina lineage that forms a large proportion of the Sebacinales order. We downloaded all publicly available internal transcribed spacer (ITS) sequences and metadata and supplemented sequence information from three genes to construct dated phylogenies and test biogeographic hypotheses. The /sebacina lineage evolved 45–57 Myr ago that groups it with relatively young EcM taxa in other studies. The most parsimonious origin for /sebacina is inferred to be North American temperate coniferous forests. Among biogeographic traits, region and biome exhibited stronger phylogenetic signal than host family. Consistent with the resource availability (environmental energy) hypothesis, the ITS region is evolving at a faster rate in tropical than nontropical regions. Most biogeographic regions exhibited substantial phylogenetic clustering suggesting a strong impact of dispersal limitation over a large geographic scale. In northern Holarctic regions, however, phylogenetic distances and phylogenetic grouping of isolates indicate multiple recent dispersal events.
Kaldor's 1970 Regional Growth Model Revisited
Authors: Thirlwall A. P.
Published: July 2014

Kaldor's 1970 paper ‘The Case for Regional Policies’ was republished in the 60th anniversary volume of the Scottish Journal of Political Economy. This article reflects on the model after more than 40 years, and argues that although it has been criticized for its deterministic nature, it has lost none of its relevance. It predates the ideas of so‐called ‘new’ growth theory, and the new economic geography of Krugman, and provides at least a partial explanation of why growth rates and levels of per capita income between regions and between countries can continue to persist and even widen in contrast to the predictions of orthodox equilibrium theory.
Target Enzyme Mutations Confer Differential Echinocandin Susceptibilities in Candida kefyr
Authors: Staab Janet F. , Neofytos Dionysios , Rhee Peter , Jiménez-Ortigosa Cristina , Zhang Sean X. , Perlin David S. , Marr Kieren A.
Published: July 2014

Candida kefyr
is an increasingly reported pathogen in patients with hematologic malignancies. We studied a series of bloodstream isolates that exhibited reduced echinocandin susceptibilities (RES). Clinical and surveillance isolates were tested for susceptibilities to all three echinocandins, and those isolates displaying RES to one or more echinocandins were selected for molecular and biochemical studies. The isolates were analyzed for genetic similarities, and a subset was analyzed for mutations in the echinocandin target gene
FKS1
and glucan synthase echinocandin sensitivities using biochemical methods. The molecular typing did not indicate strong genetic relatedness among the isolates except for a series of strains recovered from a single patient. Two unrelated isolates with RES had previously uncharacterized
FKS1
mutations: R647G and deletion of amino acid 641 (F641Δ). Biochemical analysis of the semipurified R647G glucan synthase generated differential echinocandin sensitivity (resistance to micafungin only), while the deletion of F641 resulted in a glucan synthase highly insensitive to all three echinocandins. The consecutive isolates from a single patient with RES all harbored the common S645P mutation, which conferred resistance to all three echinocandins. The MIC values paralleled the glucan synthase inhibition kinetic data, although the S645P isolates displayed relatively higher susceptibility to caspofungin (2 μg/ml) than the other two echinocandins (>8 μg/ml). These findings highlight novel and common
FKS1
mutations in
C. kefyr
isolates. The observation of differential susceptibilities to echinocandins may provide important mechanistic insights for echinocandin antifungals.
Improving the Role and Contribution of Pharmacokinetic Analyses in Antimalarial Drug Clinical Trials
Authors: Kay Katherine , Hodel Eva Maria , Hastings Ian M.
Published: July 2014

It is now World Health Organization (WHO) policy that drug concentrations on day 7 be measured as part of routine assessment in antimalarial drug efficacy trials. The rationale is that this single pharmacological measure serves as a simple and practical predictor of treatment outcome for antimalarial drugs with long half-lives. Herein we review theoretical data and field studies and conclude that the day 7 drug concentration (d7c) actually appears to be a poor predictor of therapeutic outcome. This poor predictive capability combined with the fact that many routine antimalarial trials will have few or no failures means that there appears to be little justification for this WHO recommendation. Pharmacological studies have a huge potential to improve antimalarial dosing, and we propose study designs that use more-focused, sophisticated, and cost-effective ways of generating these data than the mass collection of single d7c concentrations.
Coinfection with an Intestinal Helminth Impairs Host Innate Immunity against Salmonella enterica Serovar Typhimurium and Exacerbates Intestinal Inflammation in Mice
Authors: Su Libo , Su Chien-wen , Qi Yujuan , Yang Guilian , Zhang Mei , Cherayil Bobby J. , Zhang Xichen , Shi Hai Ning
Published: July 2014

Salmonella enterica
serovar Typhimurium is a Gram-negative food-borne pathogen that is a major cause of acute gastroenteritis in humans. The ability of the host to control such bacterial pathogens may be influenced by host immune status and by concurrent infections. Helminth parasites are of particular interest in this context because of their ability to modulate host immune responses and because their geographic distribution coincides with those parts of the world where infectious gastroenteritis is most problematic. To test the hypothesis that helminth infection may negatively regulate host mucosal innate immunity against bacterial enteropathogens, a murine coinfection model was established by using the intestinal nematode
Heligmosomoides polygyrus
and
S
. Typhimurium. We found that mice coinfected with
S
. Typhimurium and
H. polygyrus
developed more severe intestinal inflammation than animals infected with
S
. Typhimurium alone. The enhanced susceptibility to
Salmonella
-induced intestinal injury in coinfected mice was found to be associated with diminished neutrophil recruitment to the site of bacterial infection that correlated with decreased expression of the chemoattractants CXCL2/macrophage inflammatory protein 2 (MIP-2) and CXCL1/keratinocyte-derived chemokine (KC), poor control of bacterial replication, and exacerbated intestinal inflammation. The mechanism of helminth-induced inhibition of MIP-2 and KC expression involved interleukin-10 (IL-10) and, to a lesser extent, IL-4 and IL-13. Ly6G antibody-mediated depletion of neutrophils reproduced the adverse effects of
H. polygyrus
on
Salmonella
infection. Our results suggest that impaired neutrophil recruitment is an important contributor to the enhanced severity of
Salmonella
enterocolitis associated with helminth coinfection.
Massive Diversification in Aging Colonies of Escherichia coli
Authors: Saint-Ruf Claude , Garfa-Traoré Meriem , Collin Valérie , Cordier Corinne , Franceschi Christine , Matic Ivan
Published: July 2014

The evolutionary success of bacteria depends greatly on their capacity to continually generate phenotypic diversity. Structured environments are particularly favorable for diversification because of attenuated clonal interference, which renders selective sweeps nearly impossible and enhances opportunities for adaptive radiation. We examined at the microscale level the emergence and the spatial and temporal dynamics of phenotypic diversity and their underlying causes in
Escherichia coli
colonies. An important dynamic heterogeneity in the growth, metabolic activity, morphology, gene expression patterns, stress response induction, and death patterns among cells within colonies was observed. Genetic analysis indicated that the phenotypic variation resulted mostly from mutations and that indole production, oxidative stress, and the RpoS-regulated general stress response played an important role in the generation of diversity. We observed the emergence and persistence of phenotypic variants within single colonies that exhibited variable fitness compared to the parental strain. Some variants showed improved capacity to produce biofilms, whereas others were able to use different nutrients or to tolerate antibiotics or oxidative stress. Taken together, our data show that bacterial colonies provide an ecological opportunity for the generation and maintenance of vast phenotypic diversity, which may increase the probability of population survival in unpredictable environments.
Agrobacterium tumefaciens ExoR Controls Acid Response Genes and Impacts Exopolysaccharide Synthesis, Horizontal Gene Transfer, and Virulence Gene Expression
Authors: Heckel Brynn C. , Tomlinson Amelia D. , Morton Elise R. , Choi Jeong-Hyeon , Fuqua Clay
Published: July 2014

Agrobacterium tumefaciens
is a facultative plant pathogen and the causative agent of crown gall disease. The initial stage of infection involves attachment to plant tissues, and subsequently, biofilms may form at these sites. This study focuses on the periplasmic ExoR regulator, which was identified based on the severe biofilm deficiency of
A. tumefaciens
exoR
mutants. Genome-wide expression analysis was performed to elucidate the complete ExoR regulon. Overproduction of the exopolysaccharide succinoglycan is a dramatic phenotype of
exoR
mutants. Comparative expression analyses revealed that the core ExoR regulon is unaffected by succinoglycan synthesis. Several findings are consistent with previous observations: genes involved in succinoglycan biosynthesis, motility, and type VI secretion are differentially expressed in the Δ
exoR
mutant. In addition, these studies revealed new functional categories regulated by ExoR, including genes related to virulence, conjugation of the pAtC58 megaplasmid, ABC transporters, and cell envelope architecture. To address how ExoR exerts a broad impact on gene expression from its periplasmic location, a genetic screen was performed to isolate suppressor mutants that mitigate the
exoR
motility phenotype and identify downstream components of the ExoR regulatory pathway. This suppression analysis identified the acid-sensing two-component system ChvG-ChvI, and the suppressor mutant phenotypes suggest that all or most of the characteristic
exoR
properties are mediated through ChvG-ChvI. Subsequent analysis indicates that
exoR
mutants are simulating a response to acidic conditions, even in neutral media. This work expands the model for ExoR regulation in
A. tumefaciens
and underscores the global role that this regulator plays on gene expression.
The Two-Component Regulators GacS and GacA Positively Regulate a Nonfluorescent Siderophore through the Gac/Rsm Signaling Cascade in High-Siderophore-Yielding Pseudomonas sp. Strain HYS
Authors: Yu Xinyan , Chen Min , Jiang Zhen , Hu Yi , Xie Zhixiong
Published: July 2014

Siderophores, which are produced to overcome iron deficiency, are believed to be closely related to the adaptability of bacteria. The high-siderophore-yielding
Pseudomonas
sp. strain HYS simultaneously secretes the fluorescent siderophore pyoverdine and another nonfluorescent siderophore that is a major contributor to the high siderophore yield. Transposon mutagenesis revealed siderophore-related genes, including the two-component regulators GacS/GacA and a special cluster containing four open reading frames (the
nfs
cluster). Deletion mutations of these genes abolished nonfluorescent-siderophore production, and expression of the
nfs
cluster depended on
gacA
, indicating that
gacS-gacA
may control the nonfluorescent siderophore through regulation of the
nfs
cluster. Furthermore, regulation of the nonfluorescent siderophore by GacS/GacA involved the Gac/Rsm pathway. In contrast, inactivation of GacS/GacA led to upregulation of the fluorescent pyoverdine. The two siderophores were secreted under different iron conditions, probably because of differential effects of GacS/GacA. The global GacS/GacA regulatory system may control iron uptake by modulating siderophore production and may enable bacteria to adapt to changing iron environments.
Safety culture in a pharmacy setting using a pharmacy survey on patient safety culture: a cross-sectional study in China
Authors: Jia P L , Zhang L H , Zhang M M , Zhang L L , Zhang C , Qin S F , Li X L , Liu K X
Published: July 2014

Objective

To explore the attitudes and perceptions of patient safety culture for pharmacy workers in China by using a Pharmacy Survey on Patient Safety Culture (PSOPSC), and to assess the psychometric properties of the translated Chinese language version of the PSOPSC.

Design

Cross-sectional study.

Participants

Data were obtained from 20 hospital pharmacies in the southwest part of China.

Methods

We performed χ2test to explore the differences on pharmacy staff in different hospital and qualification levels and countries towards patient safety culture. We also computed descriptive statistics, internal consistency coefficients and intersubscale correlation analysis, and then conducted an exploratory factor analysis. A test–retest was performed to assess reproducibility of the items.

Results

A total of 630 questionnaires were distributed of which 527 were responded to validly (response rate 84%). The positive response rate for each item ranged from 37% to 90%. The positive response rate on three dimensions (‘Teamwork’, ‘Staff Training and Skills’ and ‘Staffing, Work Pressure and Pace’) was higher than that of Agency for Healthcare Research and Quality (AHRQ) data (p<0.05). There was a statistical difference in the perception of patient safety culture at different hospital and qualification levels. The internal consistency of the total survey was comparatively satisfied (Cronbach's α=0.89).

Conclusions

The results demonstrated that among the pharmacy staffs surveyed in China, there was a positive attitude towards patient safety culture in their organisations. Identifying perspectives of patient safety culture from pharmacists in different hospital and qualification levels are important, since this can help support decisions about action to improve safety culture in pharmacy settings. The Chinese translation of the PSOPSC questionnaire (V.2012) applied in our study is acceptable.
Noise Effected Energy Harvesting in a Beam with Stopper
Authors: Borowiec Marek , Litak Grzegorz , Lenci Stefano
Published: July 2014

An autonomous system of energy supplier to low power devices or wireless sensors is one of the most important motivations for energy harvesting based on ambient mechanical vibrations. In traditional approach, harvesters were based on a linear mechanical resonator combined with an electro-mechanical transducer working in the resonance region, i.e. in a relatively small range of frequencies. Here, we study a frequency broadband nonlinear resonator with impact characteristics with the aim of increasing the range of operativity of the system. The excitations are modeled by kinematic forcing possessing periodic and stochastic components, motivated by realistic ambient conditions. We show how the noise component of the excitation influences the stability of the solution.
The uncertainty cascade in model fusion
Authors: Beven Keith , Lamb Rob
Published: July 2014

There are increasing demands in assessing the impacts of change on environmental systems to couple different model components together in a cascade, the outputs from one component providing the inputs to another with or without feedbacks in the coupling. Each model component will necessarily involve some uncertainty in its specification and simulations that can be conditioned using some observational data. Taking account of this uncertainty should result in more robust decision making and may change the nature of the decision made. The difficulty in environmental decision making is in making proper estimates of uncertainties when so many of the sources of uncertainty result from lack of knowledge (epistemic uncertainties) rather than uncertainty that can be treated as random variability (aleatory uncertainty). This is particularly the case for problems that involve cascades of model components. Examples are the use of UKCP09 climate scenarios in impact studies, flood risk assessment involving models of runoff generation and their impact on hydraulic models of flood plains, and integrated catchment management involving upstream to downstream surface and subsurface routing of water quality variables. The uncertainties are such that, even for relatively simple problems, they can result in wide ranges of potential outputs. This poses the questions that will be considered in this paper: how to take account of knowledge uncertainties in cascades of model components; and how to constrain the potential uncertainties for use in making decisions. In particular we highlight the difficulties of defining statistical likelihood functions that properly reflect the non-stationary uncertainty characteristics expected of epistemic sources of uncertainty.
DICE
Authors: Gună Ştefan , Mottola Luca , Picco Gian Pietro
Published: July 2014

Wireless sensor networks (WSNs) enable decentralized architectures to monitor the behavior of physical processes and to detect deviations from a specified “safe” behavior, for example, to check the operation of control loops. Such correct behavior is typically expressed by
global
invariants over the state of different sensors or actuators. Nevertheless, to leverage the computing capabilities of WSN nodes, the application intelligence needs to reside inside the network. The task of ensuring that the monitored processes behave safely thus becomes inherently distributed, and hence more complex. In this article we present DICE, a system enabling WSN-based distributed monitoring of global invariants. A DICE invariant is expressed by predicates defined over the state of multiple WSN nodes, such as the expected state of actuators based on given sensed environmental conditions. Our modular design allows two alternative protocols for detecting invariant violations: both perform in-network aggregation but with different degrees of decentralization, therefore supporting scenarios with different network and data dynamics. We characterize and compare the two protocols using large-scale simulations and a real-world testbed. Our results indicate that invariant violations are detected in a timely and energy-efficient manner. For instance, in a 225-node 15-hop network, invariant violations are detected in less than a second and with only a few packets sent by each node.
Performance Portability Across Heterogeneous SoCs Using a Generalized Library-Based Approach
Authors: Fang Shuangde , Du Zidong , Fang Yuntan , Huang Yuanjie , Chen Yang , Eeckhout Lieven , Temam Olivier , Li Huawei , Chen Yunji , Wu Chengyong
Published: July 2014

Because of tight power and energy constraints, industry is progressively shifting toward
heterogeneous
system-on-chip (SoC) architectures composed of a mix of general-purpose cores along with a number of accelerators. However, such SoC architectures can be very challenging to efficiently program for the vast majority of programmers, due to numerous programming approaches and languages. Libraries, on the other hand, provide a simple way to let programmers take advantage of complex architectures, which does not require programmers to acquire new accelerator-specific or domain-specific languages. Increasingly, library-based, also called algorithm-centric, programming approaches propose to generalize the usage of libraries and to compose programs around these libraries, instead of using libraries as mere complements.

In this article, we present a software framework for achieving
performance portability
by leveraging a generalized library-based approach. Inspired by the notion of a component, as employed in software engineering and HW/SW codesign, we advocate nonexpert programmers to write simple wrapper code around existing libraries to provide simple but necessary semantic information to the runtime. To achieve performance portability, the runtime employs machine learning (simulated annealing) to select the most appropriate accelerator and its parameters for a given algorithm. This selection factors in the possibly complex composition of algorithms used in the application, the communication among the various accelerators, and the tradeoff between different objectives (i.e., accuracy, performance, and energy).

Using a set of benchmarks run on a real heterogeneous SoC composed of a multicore processor and a GPU, we show that the runtime overhead is fairly small at 5.1% for the GPU and 6.4% for the multi-core. We then apply our accelerator selection approach to a simulated SoC platform containing multiple inexact accelerators. We show that accelerator selection together with hardware parameter tuning achieves an average 46.2% energy reduction and a speedup of 2.1× while meeting the desired application error target.
Intra-Masking Dual-Rail Memory on LUT Implementation for SCA-Resistant AES on FPGA
Authors: Hoang Anh-Tuan , Fujino Takeshi
Published: July 2014

In current countermeasure design trends against differential power analysis (DPA), security at gate level is required in addition to the security algorithm. Several dual-rail pre-charge logics (DPL) have been proposed to achieve this goal. Designs using ASIC can attain this goal owing to its backend design restrictions on placement and routing. However, implementing these designs on field programmable gate arrays (FPGA) without information leakage is still a problem because of the difficulty involved in the restrictions on placement and routing on FPGA.

This article describes our novel masked dual-rail pre-charged memory approach, called “intra-masking dual-rail memory (IMDRM) on LUT”, and its implementation on FPGA for Side-Channel Attack-resistant (SCA-resistant) AES. In the proposed design, all unsafe nodes, such as unmasking and masking, and parts of dual-rail memory with unsafe buses (buses that are not masked) are packed into a single LUT. This makes them balanced and independent of the placement and routing tools. Inputs and outputs of all LUTs are masked, and so can be considered safe signals. Several LUTs can be combined to create a safe SBox. The design is independent of the cryptographic algorithm, and hence, it can be applied to available cryptographic standards such as DES or AES as well as future standards. It requires no special placement or route constraints in its implementation. A correlation power analysis (CPA) attack on 1,000,000 traces of AES implementation on FPGA showed that the secret information is well protected against first-order side-channel attacks. Even though the number of LUTs used for memory in this implementation is seven times greater than that of the conventional unprotected single-rail memory table-lookup AES and three times greater than the implementation based on a composite field, it requires a smaller number of LUTs than all other advanced SCA-resistant implementations such as the wave dynamic differential logic, masked dual-rail pre-charge logic, and threshold.
Self-Awareness as a Model for Designing and Operating Heterogeneous Multicores
Authors: Agne Andreas , Happe Markus , Lösch Achim , Plessl Christian , Platzner Marco
Published: July 2014

Self-aware computing is a paradigm for structuring and simplifying the design and operation of computing systems that face unprecedented levels of system dynamics and thus require novel forms of adaptivity. The generality of the paradigm makes it applicable to many types of computing systems and, previously, researchers started to introduce concepts of self-awareness to multicore architectures. In our work we build on a recent reference architectural framework as a model for self-aware computing and instantiate it for an FPGA-based heterogeneous multicore running the ReconOS reconfigurable architecture and operating system. After presenting the model for self-aware computing and ReconOS, we demonstrate with a case study how a multicore application built on the principle of self-awareness, autonomously adapts to changes in the workload and system state. Our work shows that the reference architectural framework as a model for self-aware computing can be practically applied and allows us to structure and simplify the design process, which is essential for designing complex future computing systems.
A Self-Aware Tuning and Self-Aware Evaluation Method for Finite-Difference Applications in Reconfigurable Systems
Authors: Niu Xinyu , Jin Qiwei , Luk Wayne , Weston Stephen
Published: July 2014

Finite-difference methods are computationally intensive and required by many applications. Parameters of a finite-difference algorithm, such as grid size, can be varied to generate design space which contains algorithm instances with different constant coefficients. An algorithm instance with specific coefficients can either be mapped into general operators to construct static designs, or be implemented as constant-specific operators to form dynamic designs, which require runtime reconfiguration to update algorithm coefficients. This article proposes a tuning method to explore the design space to optimise both the static and the dynamic designs, and an evaluation method to select the design with maximum overall throughput, based on algorithm characteristics, design properties, available resources and runtime data size. For benchmark applications option pricing and Reverse-Time Migration (RTM), over 50% reduction in resource consumption has been achieved for both static designs and dynamic designs, while meeting precision requirements. For a single hardware implementation, the RTM design optimised with the proposed approach is expected to run 1.8 times faster than the best published design. The tuned static designs run thousands of times faster than the dynamic designs for algorithms with small data size, while the tuned dynamic designs achieve up to 5.9 times speedup over the corresponding static designs for large-scale finite-difference algorithms.
Collaborative Language Models for Localized Query Prediction
Authors: Fang Yi , Bawab Ziad Al , Crespo Jean-Francois
Published: July 2014

Localized query prediction (LQP) is the task of estimating web query trends for a specific location. This problem subsumes many interesting personalized web applications such as personalization for buzz query detection, for query expansion, and for query recommendation. These personalized applications can greatly enhance user interaction with web search engines by providing more customized information discovered from user input (i.e., queries), but the LQP task has rarely been investigated in the literature. Although exist abundant work on estimating
global
web search trends does exist, it often encounters the big challenge of data sparsity when personalization comes into play.

In this article, we tackle the LQP task by proposing a series of collaborative language models (CLMs). CLMs alleviate the data sparsity issue by collaboratively collecting queries and trend information from the other locations. The traditional statistical language models assume a fixed background language model, which loses the taste of personalization. In contrast, CLMs are personalized language models with flexible background language models customized to various locations. The most sophisticated CLM enables the collaboration to adapt to specific query topics, which further advances the personalization level. An extensive set of experiments have been conducted on a large-scale web query log to demonstrate the effectiveness of the proposed models.
Social media and college access
Authors: Ellison Nicole B. , Wohn D. Yvette , Brown Michael G.
Published: July 2014

Social media has become globally ubiquitous, transforming how people are networked and mobilized. This forum explores research and applications of these new networked publics at individual, organizational, and societal levels. ---
Shelly Farnham, Editor
Future Tense: The Chatbot and the Drone
Authors: Landis Geoffrey A.
Published: July 2014

From the intersection of computational science and technological speculation, with boundaries limited only by our ability to imagine what could be.

Autonomous or not, design is destiny.
Data dissemination performance in large-scale sensor networks
Authors: Meyfroyt Thomas M.M. , Borst Sem C. , Boxma Onno J. , Denteneer Dee
Published: July 2014

As the use of wireless sensor networks increases, the need for (energy-)efficient and reliable broadcasting algorithms grows. Ideally, a broadcasting algorithm should have the ability to quickly disseminate data, while keeping the number of transmissions low. In this paper we develop a model describing the message count in large-scale wireless sensor networks. We focus our attention on the popular Trickle algorithm, which has been proposed as a suitable communication protocol for code maintenance and propagation in wireless sensor networks. Besides providing a mathematical analysis of the algorithm, we propose a generalized version of Trickle, with an additional parameter defining the length of a listen-only period. This generalization proves to be useful for optimizing the design and usage of the algorithm. For single-cell networks we show how the message count increases with the size of the network and how this depends on the Trickle parameters. Furthermore, we derive distributions of inter-broadcasting times and investigate their asymptotic behavior. Our results prove conjectures made in the literature concerning the effect of a listen-only period. Additionally, we develop an approximation for the expected number of transmissions in multi-cell networks. All results are validated by simulations.
Studying social networks at scale
Authors: Gabielkov Maksym , Rao Ashwin , Legout Arnaud
Published: July 2014

Twitter is one of the largest social networks using exclusively directed links among accounts. This makes the Twitter social graph much closer to the social graph supporting real life communications than, for instance, Facebook. Therefore, understanding the structure of the Twitter social graph is interesting not only for computer scientists, but also for researchers in other fields, such as sociologists. However, little is known about how the information propagation in Twitter is constrained by its inner structure. In this paper, we present an in-depth study of the macroscopic structure of the Twitter social graph unveiling the highways on which tweets propagate, the specific user activity associated with each component of this macroscopic structure, and the evolution of this macroscopic structure with time for the past 6 years. For this study, we crawled Twitter to retrieve all accounts and all social relationships (follow links) among accounts; the crawl completed in July 2012 with 505 million accounts interconnected by 23 billion links. Then, we present a methodology to unveil the macroscopic structure of the Twitter social graph. This macroscopic structure consists of 8 components defined by their connectivity characteristics. Each component group users with a specific usage of Twitter. For instance, we identified components gathering together spammers, or celebrities. Finally, we present a method to approximate the macroscopic structure of the Twitter social graph in the past, validate this method using old datasets, and discuss the evolution of the macroscopic structure of the Twitter social graph during the past 6 years.
On the relevance of adversarial queueing theory in practice
Authors: Berger Daniel S. , Karsten Martin , Schmitt Jens
Published: July 2014

Adversarial Queueing Theory (AQT) has shown that seemingly innocent traffic injection rates might lead to unbounded queues in packet-switched networks - depending on scheduling strategies as well as topological characteristics. Little attention has been given to quantifying these effects in realistic network configurations. In particular, the existing AQT literature makes two unrealistic assumptions: infinite buffers and perfect synchrony. Because finite buffers inherently limit queue sizes, adversarial effects ultimately lead to packet loss which we address in this work. In addition, we study the effect of imperfect network synchronization under the packet loss metric. Our results, using analysis and simulation, indicate that classical AQT examples appear harmless under realistic assumptions but for a novel class of adversaries considerably higher loss can be observed. We introduce this class by giving examples of two new AQT concepts to construct loss-efficient network adversaries. Our analysis proves the robustness of these new adversaries against randomized de-synchronization effects in terms of variable link delays and nodal processing.
Randomized routing schemes for large processor sharing systems with multiple service rates
Authors: Mukhopadhyay Arpan , Mazumdar Ravi R.
Published: July 2014

We consider randomized job routing techniques for a system consisting of a large number of parallel processor sharing servers with heterogeneous server speeds. In particular, a scheme, that routes an incoming job request to the server providing the highest instantaneous processing rate per job among two servers, chosen uniformly at random, is proposed. We show that, unlike the homogeneous case, in the heterogeneous case, such randomized dynamic schemes need not always perform better than the optimal static scheme (in which jobs are assigned to servers with fixed probabilities independent of server states) in terms of reducing the mean response time of jobs. Specifically, we show that the stability region under the proposed scheme is a subset of that under the optimal static routing scheme. We also obtain the stationary tail distribution of server occupancies for the proposed scheme in the limit as the system size grows to infinity. This distribution has been shown to be insensitive to job length distribution and decay super-exponentially.
A comparison of core power gating strategies implemented in modern hardware
Authors: Arora Manish , Manne Srilatha , Eckert Yasuko , Paul Indrani , Jayasena Nuwan , Tullsen Dean
Published: July 2014

Idle power is a significant contributor to overall energy consumption in modern multi-core processors. Cores can enter a full-sleep state, also known as C6, to reduce idle power; however, entering C6 incurs performance and power overheads. Since power gating can result in negative savings, hardware vendors implement various algorithms to manage C6 entry. In this paper, we examine state-of-the-art C6 entry algorithms and present a comparative analysis in the context of consumer and CPU-GPU benchmarks.
What's your choice?
Authors: Ammar Ammar , Oh Sewoong , Shah Devavrat , Voloch Luis Filipe
Published: July 2014

Computing a ranking over choices using consumer data gathered from a heterogenous population has become an indispensable module for any modern consumer information system, e.g. Yelp, Netflix, Amazon and app-stores like Google play. In such applications, a ranking or recommendation algorithm needs to extract meaningful information from noisy data
accurately
and in a
scalable
manner. A principled approach to resolve this challenge requires a
model
that connects observations to recommendation decisions and a tractable inference algorithm utilizing this model. To that end, we abstract the preference data generated by consumers as noisy, partial realizations of their innate preferences, i.e. orderings or permutations over choices. Inspired by the seminal works of Samuelson (cf.
axiom of revealed preferences
) and that of McFadden (cf. discrete choice models for transportation), we model the population's innate preferences as a mixture of the so called Multi-nomial Logit (MMNL) model. Under this model, the recommendation problem boils down to (a) learning the MMNL model from population data, (b) finding am MNL component within the mixture that closely represents the revealed preferences of the consumer at hand, and (c) recommending other choices to her/him that are ranked high according to thus found component. In this work, we address the problem of learning MMNL model from partial preferences. We identify fundamental limitations of
any
algorithm to learn such a model as well as provide conditions under which, a simple, data-driven (non-parametric) algorithm learns the model effectively. The proposed algorithm has a pleasant similarity to the standard
collaborative filtering
for scalar (or star) ratings, but in the domain of permutations. This work advances the state-of-art in the domain of learning distribution over permutations (cf. [2]) as well as in the context of learning mixture distributions (cf. [4]).
Unified localization framework using trajectory signatures
Authors: Rallapalli Swati , Dong Wei , Qiu Lili , Zhang Yin
Published: July 2014

We develop a novel trajectory-based localization scheme which (i) identifies a user's current trajectory based on the measurements collected while the user is moving, by finding the best match among the training traces (trajectory matching) and then (ii) localizes the user on the trajectory (localization). The core requirement of both the steps is an accurate and robust algorithm to match two time-series that may contain significant noise and perturbation due to differences in mobility, devices, and environments. To achieve this, we develop an enhanced Dynamic Time Warping (DTW) alignment, and apply it to RSS, channel state information, or magnetic field measurements collected from a trajectory. We use indoor and outdoor experiments to demonstrate its effectiveness.
Performance analysis of MAC for power-line communications
Authors: Vlachou Christina , Banchs Albert , Herzen Julien , Thiran Patrick
Published: July 2014

We investigate the IEEE 1901 MAC protocol, the dominant protocol for high data rate power-line communications. 1901 employs a CSMA/CA mechanism similar to - but much more complex than - the backoff mechanism of 802.11. Because of this extra complexity, and although this mechanism is the only widely used MAC layer for power-line networks, there are few analytical results on its performance. We propose a model for the 1901 MAC that comes in the form of a single fixed-point equation for the collision probability. We prove that this equation admits a unique solution, and we evaluate the accuracy of our model by using simulations.
Impact of DHCP churn on network characterization
Authors: Vu Long , Turaga Deepak , Parthasarathy Srinivasan
Published: July 2014

We investigate the DHCP churn impact on network characterization by analyzing 18 months of DHCP, DNS, Firewall Alert, and Netflow data collected from an enterprise network of 30,000 clients. We find that DHCP churn has clear impact on network metrics.
Submodules in racket
Authors: Flatt Matthew
Published: July 2014

In an extensible programming language, programmers write code that must run at different times - in particular, at compile time versus run time. The module system of the Racket programming language enables a programmer to reason about programs in the face of such extensibility, because the distinction between run-time and compile-time phases is built into the language model.
Submodules
extend Racket's module system to make the phase-separation facet of the language extensible. That is, submodules give programmers the capability to define new phases, such as "test time" or "documentation time," with the same reasoning and code-management benefits as the built-in distinction between run time and compile time.
Reified type parameters using Java annotations
Authors: Gerakios Prodromos , Biboudis Aggelos , Smaragdakis Yannis
Published: July 2014

Java generics are compiled by-erasure: all clients reuse the same bytecode, with uses of the unknown type erased. C++ templates are compiled by-expansion: each type-instantiation of a template produces a different code definition. The two approaches offer trade-offs on multiple axes. We propose an extension of Java generics that allows by-expansion translation relative to selected type parameters only. This language design allows sophisticated users to get the best of both worlds at a fine granularity. Furthermore, our proposal is based on Java 8 Type Annotations (JSR 308) and the Checker Framework as an abstraction layer for controlling compilation without changes to the internals of a Java compiler.
On the simplicity of synthesizing linked data structure operations
Authors: Kurilova Darya , Rayside Derek
Published: July 2014

We argue that synthesizing operations on recursive linked data structures is not as hard as it appears and is, in fact, within reach of current SAT-based synthesis techniques - with the addition of a simple approach that we describe to decompose the problem into smaller parts. To generate smaller pieces of code,
i.e.
, shorter routines, is obviously easier than large and complex routines, and, also, there is more potential for automating the code synthesis.

In this paper, we present a code generation algorithm for synthesizing operations of linked data structures and, as an example, describe how the proposed algorithm works to synthesize operations of an AVL tree.
Modeling biology with solver-aided programming languages
Authors: Bodik Rastislav
Published: July 2014

A good model of a biological cell exposes secrets of the cell's signaling mechanisms, explaining diseases and facilitating drug discovery. Modeling cells is fundamentally a programming problem - it's programming because the model is a concurrent program that simulates the cell, and it's a problem because it is hard to write a program that reproduces all experimental observations of the cell faithfully.

In this talk, I will introduce solver-aided programming languages and show how they ease modeling biology as well as make programming accessible to non-programmers. Solver-aided languages come with constructs that delegate part of the programming problem to a constraint solver, which can be guided to synthesize parts of the program, localize its bugs, or act as a clairvoyant oracle.

I will describe our work on synthesis of stem cell models in c. elegans and then show how our framework called Rosette can rapidly implement a solver aided language in several domains, from programming by demonstration to spatial parallel programming.
Acute Brachial Artery Thrombosis in a Neonate Caused by a Peripheral Venous Catheter
Authors: Berzel Simon , Stegemann Emilia , Hertfelder Hans-Joerg , Schneider Katja , Hepping Nico
Published: July 2014

This case describes the diagnostic testing and management of an acute thrombosis of the brachial artery in a female neonate. On day seven of life, clinical signs of acutely decreased peripheral perfusion indicated an occlusion of the brachial artery, which was confirmed by high-resolution Doppler ultrasound. Imaging also showed early stages of collateralization so that surgical treatment options could be avoided. Unfractionated heparin was used initially and then replaced by low-molecular-weight heparin while coagulation parameters were monitored closely. Within several days, brachial artery perfusion was completely restored. Acetylsalicylic acid was given for additional six weeks to minimize the risk of recurring thrombosis. If inadequately fixated in a high-risk location, a peripheral venous catheter can damage adjacent structures and thus ultimately cause arterial complications.
Long‐Term Treatment with Aqueous Garlic and/or Tomato Suspensions Decreases Ehrlich Ascites Tumors
Authors: Bom Jenifer , Gunutzmann Patrícia , Hurtado Elizabeth C. Pérez , Maragno-Correa Jussara M. R. , Kleeb Silvia Regina , Lallo Maria Anete
Published: July 2014

We evaluated the preventive and therapeutic effects of aqueous suspensions of garlic, tomato, and garlic + tomato in the development of experimental Ehrlich tumors in mice. The aqueous suspensions (2%) were administered over a short term for 30 days before tumor inoculation and 12 days afterward, and suspensions at 6% were administered for 180 days before inoculation and for 12 days afterward. The volume, number, and characteristics of the tumor cells and AgNOR counts were determined to compare the different treatments. Aqueous 6% suspensions of garlic, tomato, and garlic + tomato given over the long term significantly reduced tumor growth but when given over the short term, they did not alter tumor growth.