bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mouse Model for Sublethal Leptospira interrogans Infection
Authors: Richer Luciana , Potula Hari-Hara , Melo Rita , Vieira Ana , Gomes-Solecki Maria 
Published: September 2015

ABSTRACT

Although
Leptospira
can infect a wide range of mammalian species, most studies have been conducted in golden Syrian hamsters, a species particularly sensitive to acute disease. Chronic disease has been well characterized in the rat, one of the natural reservoir hosts. Studies in another asymptomatic reservoir host, the mouse, have occasionally been done and have limited infection to mice younger than 6 weeks of age. We analyzed the outcome of sublethal infection of C3H/HeJ mice older than age 10 weeks with
Leptospira interrogans
serovar Copenhageni. Infection led to bloodstream dissemination of
Leptospira
, which was followed by urinary shedding, body weight loss, hypothermia, and colonization of the kidney by live spirochetes 2 weeks after infection. In addition,
Leptospira
dissemination triggered inflammation in the kidney but not in the liver or lung, as determined by increased levels of mRNA transcripts for the keratinocyte-derived chemokine, RANTES, macrophage inflammatory protein 2, tumor necrosis factor alpha, interleukin-1β, inducible nitric oxide synthase, interleukin-6, and gamma interferon in kidney tissue. The acquired humoral response to
Leptospira
infection led to the production of IgG mainly of the IgG1 subtype. Flow cytometric analysis of splenocytes from infected mice revealed that cellular expansion was primarily due to an increase in the levels of CD4
+
and double-negative T cells (not CD8
+
cells) and that CD4
+
T cells acquired a CD44
high
CD62L
low
effector phenotype not accompanied by increases in memory T cells. A mouse model for sublethal
Leptospira
infection allows understanding of the bacterial and host factors that lead to immune evasion, which can result in acute or chronic disease or resistance to infection (protection).
Evolution of Mycolic Acid Biosynthesis Genes and Their Regulation during Starvation in Mycobacterium tuberculosis
Authors: Jamet Stevie , Quentin Yves , Coudray Coralie , Texier Pauline , Laval Françoise , Daffé Mamadou , Fichant Gwennaele , Cam Kaymeuang 
Published: September 2015

ABSTRACTMycobacterium tuberculosis, the etiological agent of tuberculosis, is a Gram-positive bacterium with a unique cell envelope composed of an essential outer membrane. Mycolic acids, which are very-long-chain (up to C100) fatty acids, are the major components of this mycomembrane. The enzymatic pathways involved in the biosynthesis and transport of mycolates are fairly well documented and are the targets of the major antituberculous drugs. In contrast, only fragmented information is available on the expression and regulation of the biosynthesis genes. In this study, we report that thehadA,hadB, andhadCgenes, which code for the mycolate biosynthesis dehydratase enzymes, are coexpressed with three genes that encode proteins of the translational apparatus. Consistent with the well-established control of the translation potential by nutrient availability, starvation leads to downregulation of thehadABCgenes along with most of the genes required for the synthesis, modification, and transport of mycolates. The downregulation of a subset of the biosynthesis genes is partially dependent on RelMtb, the key enzyme of the stringent response. We also report the phylogenetic evolution scenario that has shaped the current genetic organization, characterized by the coregulation of thehadABCoperon with genes of the translational apparatus and with genes required for the modification of the mycolates.IMPORTANCEMycobacterium tuberculosisinfects one-third of the human population worldwide, and despite the available therapeutic arsenal, it continues to kill millions of people each year. There is therefore an urgent need to identify new targets and develop a better understanding of how the bacterium is adapting itself to host defenses during infection. A prerequisite of this understanding is knowledge of how this adaptive skill has been implanted by evolution. Nutrient scarcity is an environmental condition the bacterium has to cope with during infection. In many bacteria, adaptation to starvation relies partly on the stringent response.M. tuberculosis's unique outer membrane layer, the mycomembrane, is crucial for its viability and virulence. Despite its being the target of the major antituberculosis drugs, only scattered information exists on how the genes required for biosynthesis of the mycomembrane are expressed and regulated during starvation. This work has addressed this issue as a step toward the identification of new targets in the fight againstM. tuberculosis.
Associations of pregnancy-associated plasma protein-A level with essential hypertension and hypertensive disorders in pregnancy in Chinese population: a meta-analysis of 20 research studies involving 3332 individuals
Authors: Cai Gaojun , Zhang Bifeng , Weng Weijin , Yang Liping , Shi Ganwei , Xue Sheliang , Fu Xingli 
Published: September 2015

ObjectiveTo explore the associations between serum pregnancy-associated plasma protein-A (PAPP-A) level, and essential hypertension (EH) and hypertensive disorders in pregnancy (HDP) in Chinese population.MethodsPertinent studies were independently searched in PubMed, Embase, Cochrane Library, Chinese Biomedical Database (CBM), Wanfang databases and China National Knowledge Infrastructure (CNKI). The standardised mean difference (SMD) with 95% CIs was used to estimate the size of the effect. The subgroup analyses and meta-regression analysis were performed to identify the sources of heterogeneity among studies. Sensitivity analysis was conducted to assess the stability of the results. The publication bias between studies was examined by using Begg's funnel plots and Egger's test.ResultsA total of 20 studies involving 1493 patients and 1839 controls were included in the current meta-analysis. The PAPP-A level was significantly higher in EH patients than in controls (SMD=1.960, 95% CI 1.305 to 2.615, p<0.001), and significant associations were observed in all subgroups. The PAPP-A level was also significantly higher in HDP patients than in healthy pregnant women (SMD=2.249; 95% CI 1.324 to 3.173, p<0.001). The positive association between PAPP-A level and the risk of HDP was consistently observed in all subgroups except the subgroup with low NOS score.ConclusionsThe present meta-analysis suggests that an elevated PAPP-A level may be associated with susceptibilities to EH and HDP.
Understanding hikers who approached a hazardous river in Yosemite National Park
Authors: Girasek Deborah C , Marschall Joy S , Pope Dov 
Published: September 2015

ObjectivesTo understand the perceptions and motivations of hikers who approached a swift river at locations that have been associated with drowning in the past.MethodsA survey was completed by 399 adults who had been observed getting ‘too close’ to the Merced River. The questionnaire covered trail familiarity, information sources, timing and motivation of their decision, perceived safety, knowledge and opinion of park rules.ResultsSixty-eight per cent of invited hikers agreed to participate. Almost all had received advance information about their hike, but most often that did not include a river warning. Most respondents were observed in the risk zone by the footbridge, and their most frequent motivation was to ‘cool off’. Ninety-two per cent of hikers reported feeling very or somewhat safe by the river. Their risk perceptions did not correlate with expert ratings of danger. Males, younger subjects and those who had hiked the trail before were more likely to enter the most hazardous parts of the risk zone. Eleven per cent of people at the footbridge and 43% at the top of the waterfall thought that the park should not allow visitors to go where they had been. The most common reason they gave for this view was that the location was unsafe.ConclusionsWhile this needs assessment identified channels for informing hikers of drowning risk, there are indications that they might not personalise such warnings. Another option would be to explore cooling alternatives that could compete with the swift water that runs along many hiking trails.
Einstein–Born–Infeld black holes with a scalar hair in three dimensions
Authors: Mazharimousavi S. Habib , Halilsoy M. 
Published: September 2015

We present black hole solutions in (2+1)-dimensional Einstein’s theory of gravity coupled with Born–Infeld (BI) nonlinear electrodynamic and a massless self-interacting scalar field. The model has five free parameters: mass [Formula: see text], cosmological constant [Formula: see text], electric [Formula: see text] and scalar [Formula: see text] charges and BI parameter [Formula: see text]. To attain exact solution for such a highly nonlinear system we adjust, i.e. finely tune, the parameters of the theory with the integration constants. In the limit [Formula: see text], we recover the results of Einstein–Maxwell–Scalar theory, obtained before. The self-interacting potential admits finite minima apt for the vacuum contribution. Hawking temperature of the model is investigated versus properly tuned parameters. By employing this tuned-solution as basis, we obtain also a dynamic solution which in the proper limit admits the known solution in Einstein gravity coupled with self-interacting scalar field. Finally, we establish the equations of a general scalar–tensor field coupled to nonlinear electrodynamics (NED) field in 2+1 dimensions without searching for exact solutions.
New experimental method to study the combined effect of temperature and salt weathering
Authors: Hamed Ayman , Aly Nevin , Gomez-Heras Miguel , Alvarez de Buergo Monica 
Published: September 2015

Abstract
This study presents a new experimental chamber, which builds upon previous methods of testing salt weathering. This method is based on capillary rising in samples, as this corresponds to the actual imbibition process in building stone. This set-up allows control in setting both a specific thermal regime and cycling temperatures. Some of the significant additions of this experimental set-up are: continuous flow of the saline solution, as the samples will be fed with a constant concentration throughout the experiments; and continuous monitoring of environmental temperature, relative humidity and sample weights. Recorded results in this research belong to limestone samples from Mokattam, Cairo. Results are also considered as a proof to the practical advantages of the experimental chamber in salt-weathering studies and its environmental controls.
Memory-Model-Aware Testing
Authors: Furbach Florian , Meyer Roland , Schneider Klaus , Senftleben Maximilian 
Published: September 2015

To improve the performance of the memory system, multiprocessors implement weak memory consistency models. Weak memory models admit different views of the processes on their load and store instructions, thus allowing for computations that are not sequentially consistent. Program analyses have to take into account the memory model of the targeted hardware. This is challenging because numerous memory models have been developed, and every memory model requires its own analysis.
In this article, we study a prominent approach to program analysis: testing. The testing problem takes as input sequences of operations, one for each process in the concurrent program. The task is to check whether these sequences can be interleaved to an execution of the entire program that respects the constraints of a memory model under consideration. We determine the complexity of the testing problem for most of the known memory models. Moreover, we study the impact on the complexity of parameters, such as the number of concurrent processes, the length of their executions, and the number of shared variables.

What differentiates our contribution from related results is a uniform approach that avoids considering each memory model on its own. We build upon work of Steinke and Nutt. They showed that the existing memory models form a hierarchy where one model is called weaker than another one if it includes the latter’s behavior. Using the Steinke-Nutt hierarchy, we develop three general concepts that allow us to quickly determine the complexity of a testing problem. First, we generalize the technique of problem reductions from complexity theory. So-called range reductions propagate hardness results between memory models, and we apply them to establish
NP
lower bounds for the stronger memory models. Second, for the weaker models, we present polynomial-time testing algorithms that are inspired by determinization algorithms for automata. Finally, we describe a single SAT encoding of the testing problem that works for all memory models in the Steinke-Nutt hierarchy to prove their membership in
NP
. Our results are general enough to carry over to future weak memory models. Moreover, they show that SAT solvers are adequate tools for testing.
Spatiotemporal Traffic Matrix Synthesis
Authors: Tune Paul , Roughan Matthew 
Published: September 2015

Traffic matrices describe the volume of traffic between a set of sources and destinations within a network. These matrices are used in a variety of tasks in network planning and traffic engineering, such as the design of network topologies. Traffic matrices naturally possess complex spatiotemporal characteristics, but their proprietary nature means that little data about them is available publicly, and this situation is unlikely to change.
Our goal is to develop techniques to synthesize traffic matrices for researchers who wish to test new network applications or protocols. The paucity of available data, and the desire to build a general framework for synthesis that could work in various settings requires a new look at this problem. We show how the principle of maximum entropy can be used to generate a wide variety of traffic matrices constrained by the needs of a particular task, and the available information, but otherwise avoiding hidden assumptions about the data. We demonstrate how the framework encompasses existing models and measurements, and we apply it in a simple case study to illustrate the value.
Practical, Real-time Centralized Control for CDN-based Live Video Delivery
Authors: Mukerjee Matthew K. , Naylor David , Jiang Junchen , Han Dongsu , Seshan Srinivasan , Zhang Hui 
Published: September 2015

Live video delivery is expected to reach a peak of 50 Tbps this year. This surging popularity is fundamentally changing the Internet video delivery landscape. CDNs must meet users' demands for fast join times, high bitrates, and low buffering ratios, while minimizing their own cost of delivery and responding to issues in real-time. Wide-area latency, loss, and failures, as well as varied workloads ("mega-events" to long-tail), make meeting these demands challenging.
An analysis of video sessions concluded that a centralized controller could improve user experience, but CDN systems have shied away from such designs due to the difficulty of quickly handling failures, a requirement of both operators and users. We introduce VDN, a practical approach to a video delivery network that uses a centralized algorithm for live video optimization. VDN provides CDN operators with real-time, fine-grained control. It does this in spite of challenges resulting from the wide-area (e.g., state inconsistency, partitions, failures) by using a hybrid centralized+distributed control plane, increasing average bitrate by 1.7x and decreasing cost by 2x in different scenarios.
Sub-Nanosecond Time of Flight on Commercial Wi-Fi Cards
Authors: Vasisht Deepak , Kumar Swarun , Katabi Dina 
Published: September 2015

The time-of-flight of a signal captures the time it takes to propagate from a transmitter to a receiver. Time-of-flight is perhaps the most intuitive method for localization using wireless signals. If one can accurately measure the time-of-flight from a transmitter, one can compute the transmitter's distance simply by multiplying the time-of-flight by the speed of light. Today, GPS, the most widely used outdoor localization system, localizes a device using the time-of-flight of radio signals from satellites. However, applying the same concept to indoor localization has proven difficult. Systems for localization in indoor spaces are expected to deliver high accuracy (e.g., a meter or less) using consumer-oriented technologies (e.g., Wi-Fi on one's cellphone). Unfortunately, past work could not measure time-of-flight at such an accuracy on Wi-Fi devices. As a result, over the years, research on accurate indoor positioning has moved towards more complex alternatives such as employing large multi-antenna arrays to compute the angle-of-arrival of the signal. These new techniques have delivered highly accurate indoor localization systems. Despite these advances, time-of-flight based localization has some of the basic desirable features that state-of-the-art indoor localization systems lack. In particular, measuring time-of-flight does not require more than a single antenna on the receiver. In fact, by measuring time-of-flight of a signal to just two antennas, a receiver can intersect the corresponding distances to locate its source. Thus, a receiver can locate a wireless transmitter with no support from the surrounding infrastructure. This is quite unlike current indoor localization systems, which require multiple access points at known locations, to find the distance between a pair of mobile devices. Furthermore, each of these access points need to have many antennas -- far beyond what is supported in commercial Wi-Fi devices.
In this demo, we will present Chronos, a system that combines a set of novel algorithms to measure the time-of-flight to sub-nanosecond accuracy on commercial Wi-Fi cards. In particular, we will measure distance/time-of-flight between two devices equipped with commercial Wi-Fi cards, without any support from the infrastructure or environment fingerprinting.
Vascular Smooth Muscle Cell Senescence Promotes Atherosclerosis and Features of Plaque Vulnerability
Authors: Wang Julie , Uryga Anna K. , Reinhold Johannes , Figg Nichola , Baker Lauren , Finigan Alison , Gray Kelly , Kumar Sheetal , Clarke Murray , Bennett Martin 
Published: September 2015

Background—
Although vascular smooth muscle cell (VSMC) proliferation is implicated in atherogenesis, VSMCs in advanced plaques and cultured from plaques show evidence of VSMC senescence and DNA damage. In particular, plaque VSMCs show shortening of telomeres, which can directly induce senescence. Senescence can have multiple effects on plaque development and morphology; however, the consequences of VSMC senescence or the mechanisms underlying VSMC senescence in atherosclerosis are mostly unknown.

Methods and Results—

We examined the expression of proteins that protect telomeres in VSMCs derived from human plaques and normal vessels. Plaque VSMCs showed reduced expression and telomere binding of telomeric repeat-binding factor-2 (TRF2), associated with increased DNA damage. TRF2 expression was regulated by p53-dependent degradation of the TRF2 protein. To examine the functional consequences of loss of TRF2, we expressed TRF2 or a TRF2 functional mutant (T188A) as either gain- or loss-of-function studies in vitro and in apolipoprotein E
–/–
mice. TRF2 overexpression bypassed senescence, reduced DNA damage, and accelerated DNA repair, whereas TRF2
188A
showed opposite effects. Transgenic mice expressing VSMC-specific TRF2
T188A
showed increased atherosclerosis and necrotic core formation in vivo, whereas VSMC-specific TRF2 increased the relative fibrous cap and decreased necrotic core areas. TRF2 protected against atherosclerosis independent of secretion of senescence-associated cytokines.

Conclusions—
We conclude that plaque VSMC senescence in atherosclerosis is associated with loss of TRF2. VSMC senes cence promotes both atherosclerosis and features of plaque vulnerability, identifying prevention of senescence as a potential target for intervention.
On the Variability and Predictability of Eastern Pacific Tropical Cyclone Activity*
Authors: Caron Louis-Philippe , Boudreault Mathieu , Camargo Suzana J. 
Published: September 2015

AbstractVariability in tropical cyclone activity in the eastern Pacific basin has been linked to a wide range of climate factors, yet the dominant factors driving this variability have yet to be identified. Using Poisson regressions and a track clustering method, the authors analyze and compare the climate influence on cyclone activity in this region. The authors show that local sea surface temperature and upper-ocean heat content as well as large-scale conditions in the northern Atlantic are the dominant influence in modulating eastern North Pacific tropical cyclone activity. The results also support previous findings suggesting that the influence of the Atlantic Ocean occurs through changes in dynamical conditions over the eastern Pacific. Using model selection algorithms, the authors then proceed to construct a statistical model of eastern Pacific tropical cyclone activity. The various model selection techniques used agree in selecting one predictor from the Atlantic (northern North Atlantic sea surface temperature) and one predictor from the Pacific (relative sea surface temperature) to represent the best possible model. Finally, we show that this simple model could have predicted the anomalously high level of activity observed in 2014.
EnKF and Hybrid Gain Ensemble Data Assimilation. Part II: EnKF and Hybrid Gain Results
Authors: Bonavita Massimo , Hamrud Mats , Isaksen Lars 
Published: September 2015

Abstract
The desire to do detailed comparisons between variational and more scalable ensemble-based data assimilation systems in a semioperational environment has led to the development of a state-of-the-art EnKF system at ECMWF, which has been described in Part I of this two-part study. In this part the performance of the EnKF system is evaluated compared to a 4DVar of similar resolution. It is found that there is not a major difference between the forecast skill of the two systems. However, similarly to the operational hybrid 4DVar–EDA, a hybrid EnKF–variational system [which we refer to as the hybrid gain ensemble data assimilation (HG-EnDA)] is capable of significantly outperforming both component systems. The HG-EnDA has been implemented with relatively little effort following Penny’s recent study. Results of numerical experimentation comparing the HG-EnDA with the hybrid 4DVar–EDA used operationally at ECMWF are presented, together with diagnostic results, which help characterize the behavior of the proposed ensemble data assimilation system. A discussion of these results in the context of hybrid data assimilation in global NWP is also provided.