Using Tuangou to reduce IP transit costs

A majority of ISPs (Internet Service Providers) support connectivity to the entire Internet by transiting their traffic via other providers. Although the transit prices per Mbps decline steadily, the overall transit costs of these ISPs remain high or even increase, due to the traffic growth. The discontent of the ISPs with the high transit costs has yielded notable innovations such as peering, content distribution networks, multicast, and peer-to-peer localization. While the above solutions tackle the problem by reducing the transit traffic, this paper explores a novel approach that reduces the transit costs without altering the traffic. In the proposed CIPT (Cooperative IP Transit), multiple ISPs cooperate to jointly purchase IP (Internet Protocol) transit in bulk. The aggregate transit costs decrease due to the economies-of-scale effect of typical subadditive pricing as well as burstable billing: not all ISPs transit their peak traffic during the same period. To distribute the aggregate savings among the CIPT partners, we propose Shapley-value sharing of the CIPT transit costs. Using public data about IP traffic of 264 ISPs and transit prices, we quantitatively evaluate CIPT and show that significant savings can be achieved, both in relative and absolute terms. We also discuss the organizational embodiment, relationship with transit providers, traffic confidentiality, and other aspects of CIPT

FeNi-based magnetoimpedance multilayers: Tailoring of the softness by magnetic spacers

The microstructure and magnetic properties of sputtered permalloy films and FeNi(170 nm)/X/FeNi(170 nm) (X=Co, Fe, Gd, Gd-Co) sandwiches were studied. Laminating of the thick FeNi film with various spacers was done in order to control the magnetic softness of FeNi-based multilayers. In contrast to the Co and Fe spacers, Gd and Gd-Co magnetic spacers improved the softness of the FeNi/X/FeNi sandwiches. The magnetoimpedance responses were measured for [FeNi/Ti(6 nm)] 2/FeNi and [FeNi/Gd(2 nm)] 2/FeNi multilayers in a frequency range of 1-500 MHz: for all frequencies under consideration the highest magnetoimpedance variation was observed for [FeNi/Gd(2 nm)] 2/FeNi multilayers. © 2012 American Institute of Physics

Discovery of a Low-Mass Brown Dwarf Companion of the Young Nearby Star G196-3

A substellar-mass object in orbit at about 300 astronomical units (AU) from the young low-mass star G196-3 was detected by direct imaging. Optical and infrared photometry and low- and intermediate-resolution spectroscopy of the faint companion, hereafter referred to as G196-3B, confirms its cool atmosphere and allows its mass to be estimated at 25^{+15}_{-10} Jupiter masses. The separation between both objects and their mass ratio suggest the fragmentation of a collapsing cloud as the most likely origin for G196-3B, but alternatively it could have originated from a proto-planetary disc which has been dissipated. Whatever the formation process was, the young age of the primary star (about 100 Myr) demonstrates that substellar companions can form in short time scales.Comment: Published in Science (13 Nov). One color figur

Nanostructured giant magneto-impedance multilayers deposited onto flexible substrates for low pressure sensing

Nanostructured FeNi-based multilayers are very suitable for use as magnetic sensors using the giant magneto-impedance effect. New fields of application can be opened with these materials deposited onto flexible substrates. In this work, we compare the performance of samples prepared onto a rigid glass substrate and onto a cyclo olefin copolymer flexible one. Although a significant reduction of the field sensitivity is found due to the increased effect of the stresses generated during preparation, the results are still satisfactory for use as magnetic field sensors in special applications. Moreover, we take advantage of the flexible nature of the substrate to evaluate the pressure dependence of the giant magneto-impedance effect. Sensitivities up to 1 Ω/Pa are found for pressures in the range of 0 to 1 Pa, demostrating the suitability of these nanostructured materials deposited onto flexible substrates to build sensitive pressure sensors

Endothelium in diseased states

International audienc

Does swimming styles specialization influence the hamstring muscle extensibility?

El objetivo de este estudio es comprobar si el estilo de natación en el que están especializados los nadadores, influye sobre la extensibilidad isquiosural de los deportistas que han participado en esta investigación. El test empleado para este trabajo es el test “sit and reach”. Se ha medido la extensibilidad isquiosural de todos los nadadores (N=36) de ambos sexos, que entrenan en un centro de tecnificación acuático español. La edad de los participantes del estudio oscila entre los 13 y los 17 años. Esta población de nadadores ha sido dividida en cuatro grupos diferentes, dependiendo del estilo de natación en el que están especializados (crol, espalda, braza y mariposa). Para conocer la influencia del estilo natación sobre los resultados obtenidos en el test “sit and reach”, se ha aplicado un test inicial y nueve meses más tarde un test final, lo que ha permitido conocer también la evolución de las mediciones Como conclusión, la extensibilidad isquiosural y su evolución, no está condicionada por el estilo de natación en el que están especializados los nadadores que han participado en este estudioThe aim of this research is to verify the swimming style in which swimmers are specialized, have has influences hamstring extensibility athletes who have had participated in this research. The employed test for this work was the “sits and reach" test. It was measured hamstring extensibility of all swimmers (N = 36) of both sexes, who train in Spanish aquatic center modernization. The age of the study participants is between 13 and 17 years. This population of swimmers has been divided into four different groups, depending on the style of swimming in which they are specialized (crawl, backstroke, breaststroke and butterfly). To determine the influence of swimming style on the results obtained in the test "sit and reach", it having had applied an initial test before, and a final test nine months later, which have had permitted also know the measurements evolution. In conclusion, the hamstring muscle extensibility and its evolution have had being not conditioned by swimming style of the swimmer

«La gitanilla» (Anónimo, 1914) y «La ilustre fregona» (Francisco Carrillo Casado, 1926): dos guiones cervantinos del cine mudo

This paper recovers two scripts from the silent era: La gitanilla (Anonymous, 1914) –preserved in the Bibliothèque Nationale de France– and La ilustre fregona (Francisco Carrillo Casado, 1926) –Biblioteca Nacional de España–, based on the homonymous tales by Cervantes (Novelas ejemplares, 1613). First, I will look over the lost adaptations of the whole Baroque collection; I will examine next the concept of “script” in silent film; and, finally, I will delve into this pair of rewrites, paying attention to both their peculiar form and their differences from the base texts.El presente artículo rescata un par de guiones del cine primitivo: La gitanilla (Anónimo, 1914) –conservado en la Bibliothèque Nationale de France– y La ilustre fregona (Francisco Carrillo Casado, 1926) –Biblioteca Nacional de España–, basados en sendos relatos de Cervantes (Novelas ejemplares, 1613). Primero, pasaré revista a las adaptaciones perdidas de la colección barroca; sondearé después el concepto de “guion” en la era muda; y, por último, profundizaré en ambas reescrituras, atendiendo tanto a su peculiaridad formal como a sus divergencias argumentales respecto a los textos base

Mechanomodulation of Lipid Membranes by Weakly Aggregating Silver Nanoparticles

Silver nanoparticles (AgNPs) have wide-ranging applications, including as additives in consumer products and in medical diagnostics and therapy. Therefore, understanding how AgNPs interact with biological systems is important for ascertaining any potential health risks due to the likelihood of high levels of human exposure. Besides any severe, acute effects, it is desirable to understand more subtle interactions that could lead to milder, chronic health impacts. Nanoparticles are small enough to be able to enter biological cells and interfere with their internal biochemistry. The initial contact between the nanoparticle and cell is at the plasma membrane. To gain fundamental mechanistic insight into AgNP–membrane interactions, we investigate these phenomena in minimal model systems using a wide range of biophysical approaches applied to lipid vesicles. We find a strong dependence on the medium composition, where colloidally stable AgNPs in a glucose buffer have a negligible effect on the membrane. However, at physiological salt concentrations, the AgNPs start to weakly aggregate and sporadic but significant membrane perturbation events are observed. Under these latter conditions, transient poration and structural remodeling of some vesicle membranes are observed. We observe that the fluidity of giant vesicle membranes universally decreases by an average of 16% across all vesicles. However, we observe a small population of vesicles that display a significant change in their mechanical properties with lower bending rigidity and higher membrane tension. Therefore, we argue that the isolated occurrences of membrane perturbation by AgNPs are due to low-probability mechanomodulation by AgNP aggregation at the membrane

Role of ADAM17 in the non-cell autonomous effects of oncogene-induced senescence

Proteomic analysis of the secretome of p95HER2-induced senescence. a MCF7 Tet-Off p95HER2 cells were cultured with or without doxycycline for 1 week and stained for senescence-associated β-galactosidase. Representative images of the stained cultures are shown. b The secretomes of the same cells as in a were analyzed by label-free quantitative proteomics. The results are shown as unsupervised hierarchical clustering analysis corresponding to three technical replicas (a-c) of two independent experiments (1 and 2). c The proteins identified in b were classified according to the presence of transmembrane or glycophosphatidylinositol domains (cell membrane), signal peptide but not transmembrane domain (secreted, canonical), or the lack of these domains (secreted, unknown). See also Additional file 2: Table S1. Doxy doxycycline. (JPEG 585 kb