4,928 research outputs found

    Schedulability-driven scratchpad memory swapping for resource-constrained real-time embedded systems

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    In resource-constrained real-time embedded systems, scratchpad memory (SPM) is utilized in place of cache to increase performance and enforce consistent behavior of both hard and soft real-time tasks via software-controlled SPM management techniques (SPMMTs). Real-time systems depend on time critical (hard) tasks to complete execution before their deadline times. Many real-time systems also depend on the execution of soft tasks that do not have to complete by hard deadlines. This thesis evaluates a new SPMMT that increases both worst-case task slack time (TST) and soft task processing capabilities, by combining two existing SPMMTs. The schedulability-driven ACETRB / WCETRB swapping (SDAWS) SPMMT of this thesis uses task schedulability characteristics to control the selection of either the average-case execution time reduction based (ACETRB) SPMMT or the worst-case execution time reduction based (WCETRB) SPMMT. While the literature contains examples of combined management techniques, until now there have been none that combine both WCETRB and ACETRB SPMMTs. The advantage of combining them is to achieve WCET reduction comparable to what can be achieved with the WCETRB SPMMT, while achieving significantly reduced ACET relative to the WCETRB SPMMT. Using a stripped-down RTOS and an SPMMT simulator implemented for this work, evaluated resource-constrained scenarios show a reduction in task slack time from the SDAWS SPMMT relative to the WCETRB SPMMT between 20% and 45%. However, the evaluated scenarios also conservatively show that SDAWS can reduce ACET relative to the WCETRB SPMMT by up to 60%

    Capital account regulations and the trading system: a compatibility review

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    This repository item contains a single issue of the Pardee Center Task Force Reports, a publication series that began publishing in 2009 by the Boston University Frederick S. Pardee Center for the Study of the Longer-Range Future. Spanish version produced by the Center for the Study of State and Society, Buenos Aires. Portuguese version coordinated by Daniela Magalhaes Prates, a contributing author of the report, in collaboration with Ana Trivellato (translator), and Maria Inês Amorozo (graphic designer).This report is the product of the Pardee Center Task Force on Regulating Capital Flows for Long-Run Development and builds on the Task Force´s first report published in March 2012. The Pardee Center Task Force was convened initially in September 2011 as consensus was emerging that the global financial crisis has re-confirmed the need to regulate cross-border finance. The March 2012 report argues that international financial institutions – and in particular the International Monetary Fund – need to support measures that would allow capital account regulations (CARs) to become a standard and effective part of the macroeconomic policy toolkit. Yet some policymakers and academics expressed concern that many nations — and especially developing countries — may not have the flexibility to adequately deploy such regulations because of trade and investment treaties they are party to. In June 2012, the Pardee Center, with the Center for the Study of State and Society (CEDES) in Argentina and Global Development and Environment Institute (GDAE) at Tufts University, convened a second Task Force workshop in Buenos Aires specifically to review agreements at the WTO and various Free Trade Agreements (FTAs) and Bilateral Investment Treaties (BITs) for the extent to which the trading regime is compatible with the ability to deploy effective capital account regulations. This report presents the findings of that review, and highlights a number of potential incompatibilities found between the trade and investment treaties and the ability to deploy CARs. It also highlights an alarming lack of policy space to use CARs under a variety of FTAs and BITs—especially those involving the United States. Like the first report, it was written by an international group of experts whose goal is to help inform discussions and decisions by policymakers at the IMF and elsewhere that will have implications for the economic health and development trajectories for countries around the world

    A breathing zirconium metal-organic framework with reversible loss of crystallinity by correlated nanodomain formation

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    The isoreticular analogue of the metal-organic framework UiO-66(Zr), synthesized with the flexible trans-1,4-cyclohexanedicarboxylic acid as linker, shows a peculiar breathing behavior by reversibly losing long-range crystalline order upon evacuation. The underlying flexibility is attributed to a concerted conformational contraction of up to two thirds of the linkers, which breaks the local lattice symmetry. X-ray scattering data are described well by a nanodomain model in which differently oriented tetragonal-type distortions propagate over about 7-10 unit cells

    Using a complete spectroscopic survey to find red quasars and test the KX method

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    We present an investigation of quasar colour-redshift parameter space in order to search for radio-quiet red quasars and to test the ability of a variant of the KX quasar selection method to detect quasars over a full range of colour without bias. This is achieved by combining IRIS2 imaging with the complete Fornax Cluster Spectroscopic Survey to probe parameter space unavailable to other surveys. We construct a new sample of 69 quasars with measured bJ - K colours. We show that the colour distribution of these quasars is significantly different from that of the Large Bright Quasar Survey's quasars at a 99.9% confidence level. We find 11 of our sample of 69 quasars have signifcantly red colours (bJ - K >= 3.5) and from this, we estimate the red quasar fraction of the K <= 18.4 quasar population to be 31%, and robustly constrain it to be at least 22%. We show that the KX method variant used here is more effective than the UVX selection method, and has less colour bias than optical colour-colour selection methods.Comment: 11 pages, 14 figures, accepted for publication in MNRA

    Casimir scaling of domain wall tensions in the deconfined phase of D=3+1 SU(N) gauge theories

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    We perform lattice calculations of the spatial 't Hooft k-string tensions in the deconfined phase of SU(N) gauge theories for N=2,3,4,6. These equal (up to a factor of T) the surface tensions of the domain walls between the corresponding (Euclidean) deconfined phases. For T much larger than Tc our results match on to the known perturbative result, which exhibits Casimir Scaling, being proportional to k(N-k). At lower T the coupling becomes stronger and, not surprisingly, our calculations show large deviations from the perturbative T-dependence. Despite this we find that the behaviour proportional to k(N-k) persists very accurately down to temperatures very close to Tc. Thus the Casimir Scaling of the 't Hooft tension appears to be a `universal' feature that is more general than its appearance in the low order high-T perturbative calculation. We observe the `wetting' of these k-walls at T around Tc and the (almost inevitable) `perfect wetting' of the k=N/2 domain wall. Our calculations show that as T tends to Tc the magnitude of the spatial `t Hooft string tension decreases rapidly. This suggests the existence of a (would-be) 't Hooft string condensation transition at some temperature which is close to but below Tc. We speculate on the `dual' relationship between this and the (would-be) confining string condensation at the Hagedorn temperature that is close to but above Tc.Comment: 40 pages, 14 figure

    Shape controlled assembly of carboxylic acids : formation of a binary monolayer by intercalation into molecular nanotunnels

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    Support by the Leverhulme Trust (RGP -2013-177) and EPSRC via doctoral training grants (R .O .d.l.M .,H.A.) and the EPSRC Centre for Doctoral Training in Critical Resource Catalysis (CRITICAT) (PhD studentship to K.T.) is gratefully acknowledged. A. A. acknowledges the financial support by the DAAD-Aceh Scholarship of Excellence.Binary self-assembled monolayers (SAMs) combining a Y-shaped aromatic carboxylic acid (1,3,5-benzenetribenzoic acid, H3BTB) and a cage-type alicyclic carboxylic acid (adamantane carboxylic acid, AdCA) were investigated by scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), and near edge X-ray absorption fine structure (NEXAFS) spectroscopy. The SAMs, prepared by molecular adsorption from solution on Au substrates modified by underpotential deposition of Ag, exhibit a pronounced dependence of their structure on the assembly protocol. Exposing an H3BTB SAM to AdCA, the highly regular row structure of the native H3BTB layer persists and STM imaging does not show signs of AdCA adsorption. This is in striking contrast to the disordered arrangements of H3BTB and the presence of AdCA employing the inverted adsorption sequence or coadsorption of the two molecules. However, spectroscopic analysis of the H3BTB SAM exposed to AdCA reveals the presence also of the latter, suggesting that the AdCA molecules are hidden in the nanotunnels of the H3BTB monolayer. Direct evidence for the intercalation of AdCA is obtained by STM manipulation experiments which lay bare areas of AdCA molecules upon local removal of H3BTB. Surprisingly, these are densely packed and arranged into a highly ordered monolayer. Formation of such a compact AdCA layer is explained by expulsion of AdCA from the H3BTB nanotunnels of the surrounding intact mixed SAM, driven by release of stress in the nanotunnels built up when AdCA is intercalated.PostprintPeer reviewe

    Noninvasive Assessment of Acute Dyspnea in the ED

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    Altres ajuts: This work was supported in part by National Institutes of Health [Grants HL67181; and HL073198].We compared the ability of noninvasive measurements of cardiac output (CO) and thoracic fluid content (TFC) and their change in response to orthostatic challenges to diagnose acute decompensate heart failure (ADHF) from non-ADHF causes of acute dyspnea in patients in the ED. Forty-five patients > 44 years old presenting in the ED with dyspnea were studied. CO and TFC were monitored with a NICOM bioreactance device. CO and TFC were measured continuously while each patient was sitting, supine, and during a passive leg-raising maneuver (3 min each); the maximal values during each maneuver were reported. Orthostatic challenges were repeated 2 h into treatment. One patient was excluded because of intolerance to the supine position. Diagnoses obtained with the hemodynamic measurements were compared with ED diagnoses and with two expert physicians by chart review (used as gold standard diagnosis); both groups were blinded to CO and TFC values. Patient's treatment, ED disposition, hospital length of stay, and subjective dyspnea (Borg scale) were also recorded. Sixteen of 44 patients received a diagnosis of ADHF and 28 received a diagnosis of non-ADHF by the experts. Baseline TFC was higher in patients with ADHF (P =.001). Fifteen patients were treated for ADHF, and their Borg scale values decreased at 2 h (P <.05). TFC threshold of 78.8 had a receiver operator characteristic area under the curve of 0.81 (76% sensitivity, 71% specificity) for ADHF. Both ADHF and non-ADHF groups were similar in their increased CO from baseline to PLR and supine. Pre- and posttreatment measurements were similar. Baseline TFC can discriminate patients with ADHF from non-ADHF dyspnea in the ED

    Hedgehog/Gli supports androgen signaling in androgen deprived and androgen independent prostate cancer cells

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    <p>Abstract</p> <p>Background</p> <p>Castration resistant prostate cancer (CRPC) develops as a consequence of hormone therapies used to deplete androgens in advanced prostate cancer patients. CRPC cells are able to grow in a low androgen environment and this is associated with anomalous activity of their endogenous androgen receptor (AR) despite the low systemic androgen levels in the patients. Therefore, the reactivated tumor cell androgen signaling pathway is thought to provide a target for control of CRPC. Previously, we reported that Hedgehog (Hh) signaling was conditionally activated by androgen deprivation in androgen sensitive prostate cancer cells and here we studied the potential for cross-talk between Hh and androgen signaling activities in androgen deprived and androgen independent (AI) prostate cancer cells.</p> <p>Results</p> <p>Treatment of a variety of androgen-deprived or AI prostate cancer cells with the Hh inhibitor, cyclopamine, resulted in dose-dependent modulation of the expression of genes that are regulated by androgen. The effect of cyclopamine on endogenous androgen-regulated gene expression in androgen deprived and AI prostate cancer cells was consistent with the suppressive effects of cyclopamine on the expression of a reporter gene (luciferase) from two different androgen-dependent promoters. Similarly, reduction of smoothened (Smo) expression with siRNA co-suppressed expression of androgen-inducible KLK2 and KLK3 in androgen deprived cells without affecting the expression of androgen receptor (AR) mRNA or protein. Cyclopamine also prevented the outgrowth of AI cells from androgen growth-dependent parental LNCaP cells and suppressed the growth of an overt AI-LNCaP variant whereas supplemental androgen (R1881) restored growth to the AI cells in the presence of cyclopamine. Conversely, overexpression of Gli1 or Gli2 in LNCaP cells enhanced AR-specific gene expression in the absence of androgen. Overexpressed Gli1/Gli2 also enabled parental LNCaP cells to grow in androgen depleted medium. AR protein co-immunoprecipitates with Gli2 protein from transfected 293T cell lysates.</p> <p>Conclusions</p> <p>Collectively, our results indicate that Hh/Gli signaling supports androgen signaling and AI growth in prostate cancer cells in a low androgen environment. The finding that Gli2 co-immunoprecipitates with AR protein suggests that an interaction between these proteins might be the basis for Hedgehog/Gli support of androgen signaling under this condition.</p

    Policy makers, regulators and researchers’ perspectives on genomics research and the capacity of the National Health Research Act of 2013 to regulate genomics research in Zambia

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    Background: Health research in sub-Saharan Africa takes place against a lengthy history of exploitation and unfair collaboration. This has involved the export of samples and data from the continent for the benefit of institutions and researchers elsewhere. In this paper, we report the perspectives of people involved in conducting genomics research in Zambia and the capacity of the Health Research Act (HRA) of 2013 in regulating genomics research. Methods: We approached 14 purposively selected stakeholders involved in the development or implementation of the HRA in Zambia for in-depth interviews. These were members of research ethics committees, genomics researchers, Ministry of Health policy makers and institutional lawyers. Results: Participants reported that there are benefits in genomics research for Zambia such as diagnosing and treatment of diseases. Participants also expressed concerns, most of which were ethical in nature. Prominent concerns were on consent. Participants’ main concern was the possible misuse of samples in the future. These concerns resonated with the HRA, which prohibits the use of broad consent for the collection of samples and data for future unspecified research. The implications of this is that Zambians may not participate in any kind of health research for which the storage, sharing and re-use of data or samples is envisaged. The restrictive nature of HRA means that genomics research may be excluded from future health research collaborations, thus isolating the country from potentially beneficial health research. Some policy makers also worried the samples and data that comes from such research may be difficult to access by local scientists. Conclusion: In this article, we describe the views of Zambian policymakers on genomics research and the capacity of HRA in regulating genomics research. Our findings are relevant for the Zambian audience, and other African countries that are aiming to regulate health research, especially genomics research.</ns4:p
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