Variability-aware request replication for latency curtailment

Processing time variability is commonplace in distributed systems, where resources display disparate performance due to, e.g., different workload levels, background processes, and contention in virtualized environments. However, it is paramount for service providers to keep variability in response time under control in order to offer responsive services. We investigate how request replication can be used to exploit processing time variability to reduce response times, considering not only mean values but also the tail of the response time distribution. We focus on the distributed setup, where replication is achieved by running copies of requests on multiple servers that otherwise evolve independently, and waiting for the first replica to complete service. We construct models that capture the evolution of a system with replicated requests using approximate methods and observe that highly variable service times offer the best opportunities for replication ¿¿¿ reducing the response time tail in particular. Further, the effect of replication is non-uniform over the response time distribution: gains in one metric, e.g., the mean, can be at the cost of another, e.g., the tail percentiles. This is demonstrated in wide range of numerical virtual experiments. It can be seen that capturing service time variability is key to the evaluation of latency tolerance strategies and in their design

3D Analysis of chromosome architecture: advantages and limitations with SEM

Three-dimensional mitotic plant chromosome architecture can be investigated with the highest resolution with scanning electron microscopy compared to other microscopic techniques at present. Specific chromatin staining techniques making use of simultaneous detection of back-scattered electrons and secondary electrons have provided conclusive information on the distribution of DNA and protein in barley chromosomes through mitosis. Applied to investigate the structural effects of different preparative procedures, these techniques were the groundwork for the ``dynamic matrix model{''} for chromosome condensation, which postulates an energy-dependent process of looping and bunching of chromatin coupled with attachment to a dynamic matrix of associated protein fibers. Data from SEM analysis shows basic higher order chromatin structures: chromomeres and matrix fibers. Visualization of nanogold-labeled phosphorylated histone H3 (ser10) with high resolution on chromomeres shows that functional modifications of chromatin can be located on structural elements in a 3D context. Copyright (C) 2005 S. Karger AG, Basel

Surface model and exchange-correlation functional effects on the description of Pd/alpha-Al2O3(0001)

Published versio

Financing methods for small-scale hardwood plantations in Queensland, Australia

Under Vision 2020, a target was set in 1997 for trebling the plantation area in Australia by the year 2020. Government subsidies and extension for plantation establishment have largely disappeared, hence forestry expansion is highly dependent on access to private finance. In the state of Queensland, plantation expansion has occurred predominantly through managed investment schemes and the joint venture scheme managed by Forestry Plantations Queensland, a government-owned corporation. Most of these plantings are relatively small-scale hardwood plantations, which are designed to replace the hardwood timber from the native forests that will be protected from further logging after 2024 under the South-East Queensland Regional Forestry Agreement. Views on financing methods for forestry expansion in Queensland were investigated through by an email survey of 12 forestry and finance professionals, followed by in-depth personal interviews of the same group of key informants. Some of the issues identified include lack of transparent information, inequitable taxation system between Managed Investment Scheme (MIS) companies and small-scale forest operators, the need for further R&D on all aspects of the industry, the potential impacts of carbon credit schemes on the industry, and the design of a strategic model for forestry investors. Participants took the view that adoption of a strategic alliance model would encourage further investment in small-scale forestry, arguing that this model could protect the interest of all the stakeholders through reducing investment risk and creating competitive advantage. The potential introduction of a carbon trading scheme also attracted interest from investors, who look for recognisable structures that may alleviate the risk of investing in an industry with which they are unfamiliar. The participants considered that further R&D should be the main focus for government participation in small-scale forestry

Polonium-210 poisoning: a first-hand account

Background: Polonium-210 (210Po) gained widespread notoriety after the poisoning and subsequent death of Mr Alexander Litvinenko in London, UK, in 2006. Exposure to 210Po resulted initially in a clinical course that was indistinguishable from infection or exposure to chemical toxins, such as thallium. Methods: A 43-year-old man presented to his local hospital with acute abdominal pain, diarrhoea, and vomiting, and was admitted to the hospital because of dehydration and persistent gastrointestinal symptoms. He was initially diagnosed with gastroenteritis and treated with antibiotics. Clostridium difficile toxin was subsequently detected in his stools, which is when he first raised the possibility of being poisoned and revealed his background and former identity, having been admitted under a new identity with which he had been provided on being granted asylum in the UK. Within 6 days, the patient had developed thrombocytopenia and neutropenia, which was initially thought to be drug induced. By 2 weeks, in addition to bone marrow failure, he had evidence of alopecia and mucositis. Thallium poisoning was suspected and investigated but ultimately dismissed because blood levels of thallium, although raised, were lower than toxic concentrations. The patient continued to deteriorate and within 3 weeks had developed multiple organ failure requiring ventilation, haemofiltration, and cardiac support, associated with a drop in consciousness. On the 23rd day after he first became ill, he suffered a pulseless electrical activity cardiorespiratory arrest from which he could not be resuscitated and was pronounced dead. Findings: Urine analysis using gamma-ray spectroscopy on day 22 showed a characteristic 803 keV photon emission, raising the possibility of 210Po poisoning. Results of confirmatory analysis that became available after the patient's death established the presence of 210Po at concentrations about 109-times higher than normal background levels. Post-mortem tissue analyses showed autolysis and retention of 210Po at lethal doses in several organs. On the basis of the measured amounts and tissue distribution of 210Po, it was estimated that the patient had ingested several 1000 million becquerels (a few GBq), probably as a soluble salt (eg, chloride), which delivered very high and fatal radiation doses over a period of a few days. Interpretation: Early symptoms of 210Po poisoning are indistinguishable from those of a wide range of chemical toxins. Hence, the diagnosis can be delayed and even missed without a high degree of suspicion. Although body surface scanning with a standard Geiger counter was unable to detect the radiation emitted by 210Po, an atypical clinical course prompted active consideration of poisoning with radioactive material, with the diagnosis ultimately being made with gamma-ray spectroscopy of a urine sample

Impact of routine cryptococcal antigen screening and targeted pre-emptive fluconazole therapy in antiretroviral naive HIV-infected adults with less than 100 CD4 cells/μL: a systematic review and meta-analysis.

Cryptococcal antigen (CrAg) screening and targeted pre-emptive fluconazole in antiretroviral naive HIV-infected adults with less than 100 CD4 cells/μL seems promising to reduce the burden of cryptococcal meningitis (CM). We searched MEDLINE, EMBASE, and Web of Science and used random-effect meta-analysis to assess the prevalence of blood CrAg-positivity (31 studies; 35,644 participants) and asymptomatic CM in CrAg-positives, incidence of CM and all-cause mortality in screened participants. Pooled prevalence of blood CrAg-positivity was 6% (95%CI: 5 - 7) and asymptomatic CM in CrAg-positives was 33% (95%CI: 21 - 45). Incidence of CM without pre-emptive fluconazole was 21.4% (95%CI: 11.6 - 34.4) and 5.7% (95%CI: 3.0 - 9.7) with pre-emptive fluconazole initiated at 800 mg/day. In CrAg-positives, post-screening lumbar puncture prior to initiating pre-emptive fluconazole at 800 mg/day further reduced incidence of CM to null and showed some survival benefits. However, all-cause mortality remained significantly higher in CrAg-positives than CrAg-negatives: RR: 2.2 (95%CI: 1.7 - 2.9, p<0.001)

Higgs boson enhancement effects on squark-pair production at the LHC

We study the Higgs boson effects on third-generation squark-pair production in proton-proton collision at the CERN Large Hadron Collider (LHC), including \Stop \Stop^*, \Stop\Sbot^*, and \Sbot \Sbot^*. We found that substantial enhancement can be obtained through s-channel exchanges of Higgs bosons at large $\tan\beta$, at which the enhancement mainly comes from $b\bar b$, $b\bar c$, and $c\bar b$ initial states. We compute the complete set of electroweak (EW) contributions to all production channels. This completes previous computations in the literature. We found that the EW contributions can be significant and can reach up to 25% in more general scenarios and at the resonance of the heavy Higgs boson. The size of Higgs enhancement is comparable or even higher than the PDF uncertainties and so must be included in any reliable analysis. A full analytical computation of all the EW contributions is presented.Comment: 23 pages, 7 figures, 1 tabl

A Note on Computable Embeddings for Ordinals and Their Reverses

We continue the study of computable embeddings for pairs of structures, i.e. for classes containing precisely two non-isomorphic structures. Surprisingly, even for some pairs of simple linear orders, computable embeddings induce a non-trivial degree structure. Our main result shows that although $\{\omega \cdot 2, \omega^\star \cdot 2\}$ is computably embeddable in $\{\omega^2, {(\omega^2)}^\star\}$, the class $\{\omega \cdot k,\omega^\star \cdot k\}$ is \emph{not} computably embeddable in $\{\omega^2, {(\omega^2)}^\star\}$ for any natural number $k \geq 3$.Comment: 13 pages, accepted to CiE 202

Multi-scale three-dimensional characterization of iron particles in dusty olivine: Implications for paleomagnetism of chondritic meteorites

Dusty olivine (olivine containing multiple sub-micrometer inclusions of metallic iron) in chondritic meteorites is considered an ideal carrier of paleomagnetic remanence, capable of maintaining a faithful record of pre-accretionary magnetization acquired during chondrule formation. Here we show how the magnetic architecture of a single dusty olivine grain from the Semarkona LL3.0 ordinary chondrite meteorite can be fully characterised in three dimensions, using a combination of Focussed-Ion-Beam nanotomography (FIB-nT), electron tomography and finite-element micromagnetic modelling. We present a three-dimensional (3D) volume reconstruction of a dusty olivine grain, obtained by selective milling through a region of interest in a series of sequential 20 nm slices, which are then imaged using scanning electron microscopy. The data provide a quantitative description of the iron particle ensemble, including the distribution of particle sizes, shapes, interparticle spacings and orientations. Iron particles are predominantly oblate ellipsoids with average radii 242 ± 94 nm by 199 ± 80 nm by 123 ± 58 nm. Using analytical TEM we observe that the particles nucleate on sub-grain boundaries and are loosely arranged in a series of sheets parallel to (001) of the olivine host. This is in agreement with the orientation data collected using the FIB-nT, and highlights how the underlying texture of the dusty olivine is crystallographically constrained by the olivine host. The shortest dimension of the particles is oriented normal to the sheets and their longest dimension is preferentially aligned within the sheets. Individual particle geometries are converted to a finite-element mesh and used to perform micromagnetic simulations. The majority of particles adopt a single vortex state, with ‘bulk’ spins that rotate around a central vortex core. We observed no particles, which are in a true single domain state. The results of the micromagnetic simulations challenge some pre-conceived ideas about the remanence carrying properties of vortex states. There is often not a simple predictive relationship between the major, intermediate and minor axes of the particles and the remanence vector imparted in different fields. Although the orientation of the vortex core is determined largely by the ellipsoidal geometry (i.e., parallel to the major axis for prolate ellipsoids and parallel to the minor axis for oblate ellipsoids), the core and remanence vectors can sometimes lie at very large (tens of degree) angles to the principal axes. The subtle details of the morphology can control the overall remanence state, leading in some cases to a dominant contribution from the bulk spins to the net remanence, with profound implications for predicting the anisotropy of the sample. The particles have very high switching fields (several hundred mT), demonstrating their high stability and suitability for paleointensity studies.The research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC grant agreements 291522-3DIMAGE (P.A.M.) and 320750 - Nanopaleomagnetism (J.F.E., R.J.H., and P.A.M.). BPW and RRF were supported by NASA Emerging Worlds program grant #NNX15AH72G, the NASA Solar System Exploration and Research Virtual Institute grant #NNA14AB01A, and a generous gift from Thomas F. Peterson, Jr. The research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement No. 320832-Imagine. (W.W . and P.O.C.) W.W. was also supported for this research under NERC grant NE/J020966/1 - Predicting the reliability with which the geomagnetic field can be recorded in igneous rocks.This is the author accepted manuscript. It is currently under an indefinite embargo pending publication by the Mineralogical Society of America

Fulvestrant: pharmacokinetics and pharmacology

Fulvestrant is a new type of oestrogen receptor (ER) antagonist with no agonist activity and a novel pharmacological profile. Fulvestrant has been shown to significantly reduce cellular levels of the ER and progesterone receptor in both preclinical studies and in clinical trials of postmenopausal women with primary breast cancer. This paper reviews the pharmacokinetics and metabolism of fulvestrant, which support the rationale for drug delivery as a single, once-monthly intramuscular injection, and show that this agent has minimal potential to be the subject, or cause, of significant cytochrome p450-mediated drug interactions