A Comprehensive Analysis of Swarming-based Live Streaming to Leverage Client Heterogeneity

Due to missing IP multicast support on an Internet scale, over-the-top media streams are delivered with the help of overlays as used by content delivery networks and their peer-to-peer (P2P) extensions. In this context, mesh/pull-based swarming plays an important role either as pure streaming approach or in combination with tree/push mechanisms. However, the impact of realistic client populations with heterogeneous resources is not yet fully understood. In this technical report, we contribute to closing this gap by mathematically analysing the most basic scheduling mechanisms latest deadline first (LDF) and earliest deadline first (EDF) in a continuous time Markov chain framework and combining them into a simple, yet powerful, mixed strategy to leverage inherent differences in client resources. The main contributions are twofold: (1) a mathematical framework for swarming on random graphs is proposed with a focus on LDF and EDF strategies in heterogeneous scenarios; (2) a mixed strategy, named SchedMix, is proposed that leverages peer heterogeneity. The proposed strategy, SchedMix is shown to outperform the other two strategies using different abstractions: a mean-field theoretic analysis of buffer probabilities, simulations of a stochastic model on random graphs, and a full-stack implementation of a P2P streaming system.Comment: Technical report and supplementary material to http://ieeexplore.ieee.org/document/7497234

Transpiration of grapevines and co-habitating cover crop and weed species in a vineyard. A “snapshot” at diurnal trends

The objective of this study was to quantify transpiration rates of two cover crops, Festuca rubra subsp. rubra  (red fescue) and Medicago lupulina (black medick) and 4 weeds, Chenopodium album (fat hen), Cirsium arvense (creeping thistle), Malva neglecta (common mallow) and Taraxacum officinale (dandelion) occurring in a mixed stand in a commercial steep-slope, North-South oriented vineyard as compared to vines, cv. Riesling near Johannisberg (Rheingau), Germany. Leaf transpiration (E) was measured directly on the cover crop and weed species with a portable gas exchange measurement system. Grapevine transpiration was measured concomitantly using custommade Granier-type xylem sap flow gauges. Measurements were conducted on two days in August (15th and 22nd) in 2001 under hot and sunny conditions. All herbaceous species presented a similar diurnal pattern of E, with low values in the morning and afternoon and peak values between 12 and 15 h. In contrast E of grapevines peaked mid-morning (between 8 and 10 h) remained relatively stable until mid-afternoon (16 h) before decreasing continuously until darkness. Significant differences in E between the herbaceous species were observed throughout the day. In general transpiration rates were highest for M. neglecta and lowest for C. arvense, T. officinale and F. rubra subsp. rubra. We estimated the projected leaf area indices (leaf area per surface area covered) for each species and calculated possible transpiration rates for pure stands assuming that all leaves were well exposed. Potential transpiration rates ranged from about 1 mm d-1 (one l m-2 of soil surface) for F. rubra subsp. rubra to = 5 mm d-1 for M. neglecta as compared to only 0.9 mm d-1 for grapevine. These results underline the importance of appropriate cover crop species and the control of some weed species with respect to water use.

A literature review on surgery for cervical vagal schwannomas

Cervical vagal schwannoma is a benign, slow-growing mass, often asymptomatic, with a very low lifetime risk of malignant transformation in general population, but diagnosis is still a challenge. Surgical resection is the treatment of choice even if its close relationship with nerve fibres, from which it arises, threats vagal nerve preservation. We present a case report and a systematic review of literature. All studies on surgical resection of cervical vagal schwannoma have been reviewed. Papers matching the inclusion criteria (topic on surgical removal of cervical vagal schwannoma, English language, full text available) were selected. Fifty-three patients with vagal neck schwannoma submitted to surgery were identified among 22 studies selected. Female/male ratio was 1.5 and median age 44 years. Median diameter was 5 cm (range 2 to 10). Most schwannoma were asymptomatic (68.2%) and received an intracapsular excision (64.9%). Postoperative symptoms were reported in 22.6% of patients. Cervical vagal schwannoma is a benign pathology requiring surgical excision, but frequently postoperative complications can affect patients lifelong, so, surgical indications should be based carefully on the balance between risks and benefits

CENÁRIOS DE TRANSFRONTEIRIZAÇÕES NA AMÉRICA DO SUL. ALGUNS EXEMPLOS DE PESQUISAS RECENTES

O artigo examina cenários de transfronterizações na América do Sul, entendida como uma região geopolítica. Regiões transfronteiriças e processos de transfronteirização podem ser compreendidos em diversos aspectos como reordenação de fluxos econômicos, pessoas cruzando limites de Estados, novas conexões de infraestruturas e de informações que tendem a produzir novas interações territoriais e territórios-rede. Apresenta-se cartografias multinacionais sul-americanas em grande detalhe de dados. Propõe-se o recorte regional da Região Transfronteiriça do Iguaçu onde ocorrem intensos fluxos transfronteiriços de diversos tipos, legais e ilegais. Por fim agrega-se à análise de processos de transfronteirizações recentes fluxos migratórios internacionais transcontinentais para o Brasil

CENÁRIOS DE TRANSFRONTEIRIZAÇÕES NA AMÉRICA DO SUL. ALGUNS EXEMPLOS DE PESQUISAS RECENTES

O artigo examina cenários de transfronterizações na América do Sul, entendida como uma região geopolítica. Regiões transfronteiriças e processos de transfronteirização podem ser compreendidos em diversos aspectos como reordenação de fluxos econômicos, pessoas cruzando limites de Estados, novas conexões de infraestruturas e de informações que tendem a produzir novas interações territoriais e territórios-rede. Apresenta-se cartografias multinacionais sul-americanas em grande detalhe de dados. Propõe-se o recorte regional da Região Transfronteiriça do Iguaçu onde ocorrem intensos fluxos transfronteiriços de diversos tipos, legais e ilegais. Por fim agrega-se à análise de processos de transfronteirizações recentes fluxos migratórios internacionais transcontinentais para o Brasil

Mosquitoes Transmit Unique West Nile Virus Populations During Each Feeding Episode

Arthropod-borne viruses (arboviruses), such as Zika virus, chikungunya virus, and West Nile virus (WNV), pose continuous threats to emerge and cause large epidemics. Often, these events are associated with novel virus variants optimized for local transmission that first arise as minorities within a host. Thus, the conditions that regulate the frequency of intrahost variants are important determinants of emergence. Here, we describe the dynamics of WNV genetic diversity during its transmission cycle. By temporally sampling saliva from individual mosquitoes, we demonstrate that virus populations expectorated by mosquitoes are highly diverse and unique to each feeding episode. After transmission to birds, however, most genetic diversity is removed by strong purifying selection. Further, transmission of potentially mosquito-adaptive WNV variants is strongly influenced by genetic drift in mosquitoes. These results highlight the complex evolutionary forces a novel virus variant must overcome to alter infection phenotypes at the population level

A Theory of Cheap Control in Embodied Systems

We present a framework for designing cheap control architectures for embodied agents. Our derivation is guided by the classical problem of universal approximation, whereby we explore the possibility of exploiting the agent's embodiment for a new and more efficient universal approximation of behaviors generated by sensorimotor control. This embodied universal approximation is compared with the classical non-embodied universal approximation. To exemplify our approach, we present a detailed quantitative case study for policy models defined in terms of conditional restricted Boltzmann machines. In contrast to non-embodied universal approximation, which requires an exponential number of parameters, in the embodied setting we are able to generate all possible behaviors with a drastically smaller model, thus obtaining cheap universal approximation. We test and corroborate the theory experimentally with a six-legged walking machine. The experiments show that the sufficient controller complexity predicted by our theory is tight, which means that the theory has direct practical implications. Keywords: cheap design, embodiment, sensorimotor loop, universal approximation, conditional restricted Boltzmann machineComment: 27 pages, 10 figure

Impact of Simultaneous Exposure to Arboviruses on Infection and Transmission by Aedes aegypti Mosquitoes

The recent emergence of both chikungunya and Zika viruses in the Americas has significantly expanded their distribution and has thus increased the possibility that individuals may become infected by more than one Aedes aegypti-borne virus at a time. Recent clinical data support an increase in the frequency of coinfection in human patients, raising the likelihood that mosquitoes could be exposed to multiple arboviruses during one feeding episode. The impact of coinfection on the ability of relevant vector species to transmit any of these viruses (that is, their vector competence) has not been determined. Thus, we here expose Ae. aegypti mosquitoes to chikungunya, dengue-2 or Zika viruses, both individually and as double and triple infections. Our results show that these mosquitoes can be infected with and can transmit all combinations of these viruses simultaneously. Importantly, infection, dissemination and transmission rates in mosquitoes are only mildly affected by coinfection

Monitoring global protein thiol-oxidation and protein S-mycothiolation in Mycobacterium smegmatis under hypochlorite stress.

Hillion M, Bernhardt J, Busche T, et al. Monitoring global protein thiol-oxidation and protein S-mycothiolation in Mycobacterium smegmatis under hypochlorite stress. Sci Rep. 2017;7(1): 1195.Mycothiol (MSH) is the major low molecular weight (LMW) thiol in Actinomycetes. Here, we used shotgun proteomics, OxICAT and RNA-seq transcriptomics to analyse protein S-mycothiolation, reversible thiol-oxidations and their impact on gene expression in Mycobacterium smegmatis under hypochlorite stress. In total, 58 S-mycothiolated proteins were identified under NaOCl stress that are involved in energy metabolism, fatty acid and mycolic acid biosynthesis, protein translation, redox regulation and detoxification. Protein S-mycothiolation was accompanied by MSH depletion in the thiol-metabolome. Quantification of the redox state of 1098 Cys residues using OxICAT revealed that 381 Cys residues (33.6%) showed >10% increased oxidations under NaOCl stress, which overlapped with 40 S-mycothiolated Cys-peptides. The absence of MSH resulted in a higher basal oxidation level of 338 Cys residues (41.1%). The RseA and RshA anti-sigma factors and the Zur and NrdR repressors were identified as NaOCl-sensitive proteins and their oxidation resulted in an up-regulation of the SigH, SigE, Zur and NrdR regulons in the RNA-seq transcriptome. In conclusion, we show here that NaOCl stress causes widespread thiol-oxidation including protein S-mycothiolation resulting in induction of antioxidant defense mechanisms in M. smegmatis. Our results further reveal that MSH is important to maintain the reduced state of protein thiols