2,728 research outputs found

    Z-Axis Optomechanical Accelerometer

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    We demonstrate a z-axis accelerometer which uses waveguided light to sense proof mass displacement. The accelerometer consists of two stacked rings (one fixed and one suspended above it) forming an optical ring resonator. As the upper ring moves due to z-axis acceleration, the effective refractive index changes, changing the optical path length and therefore the resonant frequency of the optical mode. The optical transmission changes with acceleration when the laser is biased on the side of the optical resonance. This silicon nitride "Cavity-enhanced OptoMechanical Accelerometer" (COMA) has a sensitivity of 22 percent-per-g optical modulation for our highest optical quality factor (Q_o) devicesComment: Published in Proceedings of the 25th IEEE International Conference on Micro Electro Mechanical Systems (MEMS 2012), Paris, France, January 29 - Feb 2, 2012, pp. 615-61

    Diversification of a protein kinase cascade: IME-2 is involved in nonself recognition and programmed cell death in Neurospora crassa.

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    Kinase cascades and the modification of proteins by phosphorylation are major mechanisms for cell signaling and communication, and evolution of these signaling pathways can contribute to new developmental or environmental response pathways. The Saccharomyces cerevisiae kinase Ime2 has been well characterized for its role in meiosis. However, recent studies have revealed alternative functions for Ime2 in both S. cerevisiae and other fungi. In the filamentous fungus Neurospora crassa, the IME2 homolog (ime-2) is not required for meiosis. Here we determine that ime-2 interacts genetically with a transcription factor vib-1 during nonself recognition and programmed cell death (PCD). Mutations in vib-1 (Δvib-1) suppress PCD due to nonself recognition events; however, a Δvib-1 Δime-2 mutant restored wild-type levels of cell death. A role for ime-2 in the post-translational processing and localization of a mitochondrial matrix protein was identified, which may implicate mitochondria in N. crassa nonself recognition and PCD. Further, Δvib-1 strains do not produce extracellular proteases, but protease secretion reverted to near wild-type levels in a Δvib-1 Δime-2 strain. Mass spectrometry analysis revealed that the VIB-1 protein is phosphorylated at several sites, including a site that matches the IME-2 consensus. The genetic and biochemical data for ime-2 and vib-1 indicate that IME-2 is a negative regulator of VIB-1 and suggest parallel negative regulation by IME-2 of a cell death pathway in N. crassa that functions in concert with the VIB-1 cell death pathway. Thus, IME2 kinase function has evolved following the divergence of S. cerevisiae and N. crassa and provides insight into the evolution of kinases and their regulatory targets

    Albuminuria causes lysozymuria in rats with Heymann nephritis

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    Albuminuria causes lysozymuria in rats with Heymann nephritis. To determine if changes in dietary protein intake alter renal excretion of small molecular weight proteins in passive Heymann nephritis, 21 rats with passive Heymann nephritis were fed 8.5% protein for 12 days after injection with antiserum. Dietary protein intake was then increased to 40% in 10 rats (LP-HP) while 11 rats remained on 8.5% protein (LP-LP). Lysozymuria (UlysV) increased from 66.5 ±31.0 meg/day to 457.5 ± 98.0 mcg/day (P < 0.001) after five days in LP-HP, but was unchanged in LP-LP. Albuminuria (UalbV) increased only in LP-HP, from 168 ± 23 mg/day to 447 ± 45 mg/day (P < 0.001). Urinary lysozyme excretion correlated with UalbV (r = 0.737, P < 0.001), and changes in UlysV correlated with changes in UalbV (r = 0.657, P < 0.01). To determine whether the increase in UlysV was the direct effect of the change in diet, enalapril 40 mg/kg/day was administered to prevent the increase in UalbV that occurs when these rats are fed a high protein diet. Twelve rats were fed 8.5% (LP) and 10 were fed 40% protein (HP) from the time of injection with antiserum. Six LP (LPE) and five HP (HPE) received enalapril. UlysV was 873 ± 391 meg/day in HP and nearly undetectable in the other three groups. UalbV was significantly greater in HP (368 ± 60 mg/day) compared to the other three groups (114 ± 16 in LP, 136 ± 44 in HPE, 95 ± 21 in LPE). A third group of nephrotic rats, maintained on a constant diet of 21% protein had enalapril added to their drinking water. UiysV decreased from 49 ± 9 meg/day to less than 2 meg/day (P < 0.001) and UalbV decreased from 516 ± 67 to 183 ± 32 mg/day (P < 0.001). Both UlysV and UalbV remained unchanged in untreated rats. Lysozyme, an enzyme normally entirely reabsorbed by the kidney, is found in the urine of rats with passive Heymann nephritis, and increases when dietary protein intake is increased. High protein diets increase UlysV only in as much as UalbV is increased, and when UalbV is reduced by use of an angiotensin converting enzyme inhibitor in the presence of a high protein diet UlysV is reduced in a parallel fashion, suggesting that albuminuria itself decreases the capacity of the renal tubule to reabsorb lysozyme

    The risk free rate of return in property pricing

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    GFR increases before renal mass or ODC activity increase in rats fed high protein diets

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    GFR increases before renal mass or ODC activity increase in rats fed high protein diets. Consumption of a high protein diet causes renal hypertrophy and increased glomerular filtration rate (GFR). To determine the relationship between increases in GFR, renal ornithine decarboxylase activity (ODC), arginase activity, and renal growth, dietary protein intake was increased from 8.5% to 40% in 50 male Sprague-Dawley rats (HP). Forty-one rats remained on 8.5% protein as time controls (LP). Eight to 17 animals were killed daily for measurement of kidney weight (kidney wt), ODC and arginase activities, total kidney protein and DNA content. GFR increased within the first 24 hours after the increase in dietary protein and reached a maximum within 48hrs. ODC increased from 9.7 ± 0.8 U/g to a peak of 170 ± 35 U/g at 48 hours, decreasing to a stable value of 28.6 ± 8.0 U/g at 72 hours and 25.4 ± 5.1 U/g at 168 hours, a value significantly greater than that at time zero. Arginase activity did not change. Kidney wt as percent body weight (body wt) increased after the initial increase in both GFR and in ODC activity. The peak in ODC activity corresponded with the maximum increase in GFR and preceded the increase in renal mass. After GFR stabilized, ODC activity decreased to a plateau and renal growth relative to body wt ceased. The increase in kidney weight was accompanied by a parallel increase in total kidney protein. Kidney protein/ kidney DNA ratio increased significantly by 96 hours, indicating that renal hypertrophy had occurred. The sequence of these events suggests that increasing GFR may trigger the rise in ODC activity

    The eruptive history and magmatic evolution of Aluto volcano: new insights into silicic peralkaline volcanism in the Ethiopian rift

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    The silicic peralkaline volcanoes of the East African Rift are some of the least studied volcanoes on Earth. Here we bring together new constraints from fieldwork, remote sensing, geochronology and geochemistry to present the first detailed account of the eruptive history of Aluto, a restless silicic volcano located in a densely populated section of the Main Ethiopian Rift. Prior to the growth of the Aluto volcanic complex (before 500 ka) the region was characterized by a significant period of fault development and mafic fissure eruptions. The earliest volcanism at Aluto built up a trachytic complex over 8 km in diameter. Aluto then underwent large-volume ignimbrite eruptions at 316 ± 19 ka and 306 ± 12 ka developing a ~ 42 km2 collapse structure. After a hiatus of ~ 250 ka, a phase of post-caldera volcanism initiated at 55 ± 19 ka and the most recent eruption of Aluto has a radiocarbon age of 0.40 ± 0.05 cal. ka BP. During this post-caldera phase highly-evolved peralkaline rhyolite lavas, ignimbrites and pumice fall deposits have erupted from vents across the complex. Geochemical modelling is consistent with rhyolite genesis from protracted fractionation (&gt; 80%) of basalt that is compositionally similar to rift-related basalts found east of the complex. Based on the style and volume of recent eruptions we suggest that silicic eruptions occur at an average rate of 1 per 1000 years, and that future eruptions of Aluto will involve explosive emplacement of localised pumice cones and effusive obsidian coulees of volumes in the range 1–100 × 106 m3

    Malware Detection in Cloud Computing Infrastructures

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    Cloud services are prominent within the private, public and commercial domains. Many of these services are expected to be always on and have a critical nature; therefore, security and resilience are increasingly important aspects. In order to remain resilient, a cloud needs to possess the ability to react not only to known threats, but also to new challenges that target cloud infrastructures. In this paper we introduce and discuss an online cloud anomaly detection approach, comprising dedicated detection components of our cloud resilience architecture. More specifically, we exhibit the applicability of novelty detection under the one-class support Vector Machine (SVM) formulation at the hypervisor level, through the utilisation of features gathered at the system and network levels of a cloud node. We demonstrate that our scheme can reach a high detection accuracy of over 90% whilst detecting various types of malware and DoS attacks. Furthermore, we evaluate the merits of considering not only system-level data, but also network-level data depending on the attack type. Finally, the paper shows that our approach to detection using dedicated monitoring components per VM is particularly applicable to cloud scenarios and leads to a flexible detection system capable of detecting new malware strains with no prior knowledge of their functionality or their underlying instructions. Index Terms—Security, resilience, invasive software, multi-agent systems, network-level security and protection

    Assessing the impact of intra-cloud live migration on anomaly detection

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    Virtualized cloud environments have emerged as a necessity within modern unified ICT infrastructures and have established themselves as a reliable backbone for numerous always-on services. `Live' intra-cloud virtual-machine (VM) migration is a widely used technique for efficient resource management employed within modern cloud infrastructures. Despite the benefits of such functionality, there are still several security issues which have not yet been thoroughly assessed and quantified. We investigate the impact of live virtual-machine migration on state-of-the-art anomaly detection (AD) techniques (namely PCA and K-means), by evaluating live migration under various attack types and intensities. We find that the performance for both detectors degrades as shown by their Receiver Operating Characteristics (ROC) curves when intra-cloud live migration is initiated while VMs are under a netscan (NS) or a denial-of-service (DoS) attack

    Atomic environments in iron meteorites using EXAFS

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    Extended x ray absorption fine structure (EXAFS) is observed as a modulation on the high energy side of an x ray absorption edge. It occurs when the photo-ejected electron wave is scattered by neighboring atoms in a solid, and interference occurs between the outgoing and scattered waves. The result is that the absorption spectrum carries a signature that is characteristic of the identity and disposition of scattering atoms around the absorbing atom. Therefore, it may be shown that the Fourier transform of the normalized EXAFS can provide detailed information about the immediate environment of specific atoms in a solid and is ideally suited to the study of cosmic dusts. A study of cosmic dust was initiated using EXAFS and other techniques. The simplest type of cosmic material, namely iron meteorites, was investigated

    Whatever happened to brownfield land?

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