7,169 research outputs found
On the Design of Clean-Slate Network Control and Management Plane
We provide a design of clean-slate control and management plane for data networks using the abstraction of 4D architecture, utilizing and extending 4D’s concept of a logically centralized Decision plane that is responsible for managing network-wide resources. In this paper, a scalable protocol and a dynamically adaptable algorithm for assigning Data plane devices to a physically distributed Decision plane are investigated, that enable a network to operate with minimal configuration and human intervention while providing optimal convergence and robustness against failures. Our work is especially relevant in the context of ISPs and large geographically dispersed enterprise networks. We also provide an extensive evaluation of our algorithm using real-world and artificially generated ISP topologies along with an experimental evaluation using ns-2 simulator
Acts of the State and Representation in Edith Stein
This paper discusses the thesis defended by Edith Stein that certain acts can be attributed to the State. According to Stein, the State is a social structure characterized by sovereignty. As such, it is responsible for the production, interpretation, and application of law. These tasks require the performance of acts, most of which are what Stein calls “social acts” like enactments and orders. For Stein, the acts in question are made by the organs of the State, but in the name of the State, and are thus attributed to the State via a relation of representation. In the first section, the paper presents Stein’s thesis that the sovereignty of the State entails a series of legal prerogatives, which in turn result in various social acts being ascribed to the State through its representatives. In the second section, the paper critically discusses Stein’s views, notably her theory of representation, and her account of the nature of the State, while emphasizing its most interesting aspects, namely, its fine-grained analyses of the various acts that are attributed to the State
Bessel potential space on the Laguerre hypergroup
<p>Abstract</p> <p>In this article, we define the fractional differentiation <it>D<sub>δ </sub></it>of order <it>δ</it>, <it>δ </it>> 0, induced by the Laguerre operator <it>L </it>and associated with respect to the Haar measure d<it>m<sub>α</sub></it>. We obtain a characterization of the Bessel potential space <inline-formula><graphic file="1687-1847-2011-4-i1.gif"/></inline-formula> using <it>D<sub>δ </sub></it>and different equivalent norms.</p
Singular limits for 4-dimensional semilinear elliptic problems with exponential nonlinearity
Using some nonlinear domain decomposition method, we prove the existence of
singular limits for solution of semilinear elliptic problems with exponential
nonlinearity.Comment: 29 page
Development and application of an UHPLC-MS/MS method for the simultaneous determination of 17 steroidal hormones in equine serum
A new, fast and simple analytical method that is able to identify and quantify simultaneously 17 steroid hormones and metabolites (Pregnenolone, 17-OH-Pregnenolone, Progesterone, 17-OH Progesterone, Androsterone, Androstenedione, DHEA, DHEAS, Testosterone, Cortisol, Corticosterone, Aldosterone, 11-Deoxycortisol, 11-Deoxycorticosterone, Dihydrotestosterone, Estrone, Estradiol) has been developed in equine serum using the UHPLC-MS/MS technique. 400 μL of sample were deproteinized with 1000 µl of acetonitrile, evaporated, restored with 50 µl of a solution of 25% methanol and injected in UHPLC-MS/MS triple quadrupole. The recovery percentage obtained by spiking the matrix at two different concentrations with a standard mixture of steroid hormones was in all cases higher than 85.60 % and with the percentage of coefficient of variation (CV) lower than 8.37%. The range of the correlation coefficients of the calibration curves of the analyzed compounds was 0.9922–0.9986, and the limits of detection (LODs) and limits of quantification (LOQs) were in the range of 0.002–2 ng ml-1 and 0.0055-5.5 ng ml-1, respectively. The detected LOQ for testosterone (i.e. 50 pg ml-1) is two-fold lower with respect to its threshold admitted in geldings plasma (100 pg ml-1 free testosterone). The high sensitivity and the quantitative aspect of the method permitted to detect most of steroids in equine serum. Once validated, the method was used to quantify 17 steroid hormones in mare, stallion and gelding serum samples. The main steroids detected were corticosterone (range 37.25-51.26 ng ml-1) and cortisol (range 32.57-52.24 ng ml-1), followed by 17-OH-pregnenolone, dihydrotestosterone and pregnenolone
Probing single-photon ionization on the attosecond time scale
We study photoionization of argon atoms excited by attosecond pulses using an
interferometric measurement technique. We measure the difference in time delays
between electrons emitted from the and from the shell, at
different excitation energies ranging from 32 to 42 eV. The determination of
single photoemission time delays requires to take into account the measurement
process, involving the interaction with a probing infrared field. This
contribution can be estimated using an universal formula and is found to
account for a substantial fraction of the measured delay.Comment: 4 pages, 4 figures, under consideratio
Lessons from Tarceva in pancreatic cancer: where are we now, and how should future trials be designed in pancreatic cancer?
PURPOSE OF REVIEW: The recent advances in the use of targeted therapy in pancreatic cancer are based on the knowledge of genetic alterations that occur during pancreatic carcinogenesis. We describe the repository of frequent alterations targeting tumour suppressor genes and oncogenes. We focus our attention on the epidermal growth factor receptor signalling pathway, which can be activated through different alterations and seems to play a central role in the cell transformation. Multiple targeted drugs have been developed against different partners of this network trying to improve the treatment of pancreatic cancer patients. RECENT FINDINGS: Tarceva has obtained approval in the USA and Europe for metastatic pancreatic cancer with a modest increase of median survival and a 6% increase in 1-year survival rates, suggesting that only a small fraction of patients truly benefit from it. The comparison with lung and colon cancer suggests that Kras mutations could be a predictive marker of resistance. Other promising drugs targeting different partners of the epidermal growth factor receptor signalling pathway could play a synergistic role with Tarceva as inhibitors of mTOR, mitogen-activated protein kinase kinase 1, and nuclear factor-kappaB or can directly turn down Ras. SUMMARY: The biology of the epidermal growth factor receptor, mitogen-activated protein kinase, PI3K/mTOR network suggests that a combination of drugs targeting simultaneously different partners should improve survival
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