2,569 research outputs found

    A goal programming methodology for multiobjective optimization of distributed energy hubs operation

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    This paper addresses the problem of optimal energy flow management in multicarrier energy networks in the presence of interconnected energy hubs. The overall problem is here formalized by a nonlinear constrained multiobjective optimization problem and solved by a goal attainment based methodology. The application of this solution approach allows the analyst to identify the optimal operation state of the distributed energy hubs which ensures an effective and reliable operation of the multicarrier energy network in spite of large variations of load demands and energy prices. Simulation results obtained on the 30 bus IEEE test network are presented and discussed in order to demonstrate the significance and the validity of the proposed method

    Enhanced Optical 13C Hyperpolarization in Diamond Treated by High-Temperature Rapid Thermal Annealing

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    Methods of optical dynamic nuclear polarization open the door to the replenishable hyperpolarization of nuclear spins, boosting their nuclear magnetic resonance/imaging signatures by orders of magnitude. Nanodiamond powder rich in negatively charged nitrogen vacancy defect centers has recently emerged as one such promising platform, wherein 13C nuclei can be hyperpolarized through the optically pumped defects completely at room temperature. Given the compelling possibility of relaying this 13C polarization to nuclei in external liquids, there is an urgent need for the engineered production of highly “hyperpolarizable” diamond particles. Here, a systematic study of various material dimensions affecting optical 13C hyperpolarization in diamond particles is reported on. It is discovered surprisingly that diamond annealing at elevated temperatures ∼1720 °C has remarkable effects on the hyperpolarization levels enhancing them by above an order of magnitude over materials annealed through conventional means. It is demonstrated these gains arise from a simultaneous improvement in NV− electron relaxation/coherence times, as well as the reduction of paramagnetic content, and an increase in 13C relaxation lifetimes. This work suggests methods for the guided materials production of fluorescent, 13C hyperpolarized, nanodiamonds and pathways for their use as multimodal (optical and magnetic resonance) imaging and hyperpolarization agents

    APE Results of Hadron Masses in Full QCD Simulations

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    We present numerical results obtained in full QCD with 2 flavors of Wilson fermions. We discuss the relation between the phase of Polyakov loops and the {\bf sea} quarks boundary conditions. We report preliminary results about the HMC autocorrelation of the hadronic masses, on a 163×3216^3 \times 32 lattice volume, at β=5.55\beta=5.55 with ksea=0.1570k_{sea}=0.1570.Comment: 3 pages, compressed ps-file (uufiles), Contribution to Lattice 9

    K-edge X-ray absorption spectra in transition metal oxides beyond the single particle approximation: shake-up many body effects

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    The near edge structure (XANES) in K-edge X-ray absorption spectroscopy (XAS) is a widely used tool for studying electronic and local structure in materials. The precise interpretation of these spectra with the help of calculations is hence of prime importance, especially for the study of correlated materials which have a complicated electronic structure per se. The single particle approach, for example, has generally limited itself to the dominant dipolar cross-section. It has long been known however that effects beyond this approach should be taken into account, both due to the inadequacy of such calculations when compared to experiment and the presence of shake-up many-body satellites in core-level photoemission spectra of correlated materials. This effect should manifest itself in XANES spectra and the question is firstly how to account for it theoretically and secondly how to verify it experimentally. By using state-of-the-art first principles electronic structure calculations and 1s photoemission measurements we demonstrate that shake-up many-body effects are present in K-edge XAS dipolar spectra of NiO, CoO and CuO at all energy scales. We show that shake-up effects can be included in K-edge XAS spectra in a simple way by convoluting the single-particle first-principles calculations including core-hole effects with the 1s photoemission spectra. We thus describe all features appearing in the XAS dipolar cross-section of NiO and CoO and obtain a dramatic improvement with respect to the single-particle calculation in CuO. These materials being prototype correlated magnetic oxides, our work points to the presence of shake-up effects in K-edge XANES of most correlated transition metal compounds and shows how to account for them, paving the way to a precise understanding of their electronic structure.Comment: 6 pages, 4 picture

    Low Temperature Solution-Phase Deposition of SnS Thin Films

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    The solution-phase deposition of inorganic semiconductors is a promising, scalable method for the manufacture of thin film photovoltaics. Deposition of photovoltaic materials from molecular or colloidal inks offers the possibility of inexpensive, rapid, high-throughput thin film fabrication through processes such as spray coating. For example, CdTe, Cu(In,Ga)(S,Se)_2 (CIGS), and CH_3NH_3Pb(Cl,I)_3 perovskite-based thin film solar cells have been previously deposited using solution-based processes. Inks have also recently been developed for the solution deposition of Cu_2ZnSn(S,Se)_4 (CZTS) and FeS_2 (iron pyrite) absorber layers for thin film solar applications, in order to provide sustainable alternatives to materials that contain environmentally harmful heavy metals (e.g., Cd, Pb) and/or scarce elements (e.g., Te, In)

    Quenched BKB_K-parameter with the Wilson and Clover actions at β=6.0\beta = 6.0

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    We present results for the Kaon BB parameter from a sample of 200200 configurations using the Wilson action and 460460 configurations using the Clover action, on a 183×6418^3 \times 64 lattice at β=6.0\beta=6.0. A slight improvement of the chiral behaviour of BKB_K is observed due to the Clover action. We have also compared the results for BKB_K obtained from two different procedures for the boosting of the coupling constant gg. We observe a strong dependence of BKB_K on the prescription adopted for gg in the Wilson case, contrary to the results of the Clover case which are almost unaffected by the choice of gg. Combining some recently obtained non perturbative estimates for the renormalisation constants with our Clover matrix element, we observe a significant improvement in the chiral behaviour of BKB_K.Comment: 3 pages, Latex, Postscript file with figures available at ftp://hpteo.roma1.infn.it/pub/preprints/lat94/donini ; to appear in Lattice '94, Nucl. Phys. (Proc.Suppl.

    Progress and status of APEmille

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    We report on the progress and status of the APEmille project: a SIMD parallel computer with a peak performance in the TeraFlops range which is now in an advanced development phase. We discuss the hardware and software architecture, and present some performance estimates for Lattice Gauge Theory (LGT) applications.Comment: Talk presented at LATTICE97, 3 pages, Late

    Upregulation of the Adhesin Gene EPA1 Mediated by PDR1 in Candida glabrata Leads to Enhanced Host Colonization.

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    Candida glabrata is the second most common Candida species causing disseminated infection, after C. albicans. C. glabrata is intrinsically less susceptible to the widely used azole antifungal drugs and quickly develops secondary resistance. Resistance typically relies on drug efflux with transporters regulated by the transcription factor Pdr1. Gain-of-function (GOF) mutations in PDR1 lead to a hyperactive state and thus efflux transporter upregulation. Our laboratory has characterized a collection of C. glabrata clinical isolates in which azole resistance was found to correlate with increased virulence in vivo. Contributing phenotypes were the evasion of adhesion and phagocytosis by macrophages and an increased adhesion to epithelial cells. These phenotypes were found to be dependent on PDR1 GOF mutation and/or C. glabrata strain background. In the search for the molecular effectors, we found that PDR1 hyperactivity leads to overexpression of specific cell wall adhesins of C. glabrata. Further study revealed that EPA1 regulation, in particular, explained the increase in adherence to epithelial cells. Deleting EPA1 eliminates the increase in adherence in an in vitro model of interaction with epithelial cells. In a murine model of urinary tract infection, PDR1 hyperactivity conferred increased ability to colonize the bladder and kidneys in an EPA1-dependent way. In conclusion, this study establishes a relationship between PDR1 and the regulation of cell wall adhesins, an important virulence attribute of C. glabrata. Furthermore, our data show that PDR1 hyperactivity mediates increased adherence to host epithelial tissues both in vitro and in vivo through upregulation of the adhesin gene EPA1. IMPORTANCE Candida glabrata is an important fungal pathogen in human diseases and is also rapidly acquiring drug resistance. Drug resistance can be mediated by the transcriptional activator PDR1, and this results in the upregulation of multidrug transporters. Intriguingly, this resistance mechanism is associated in C. glabrata with increased virulence in animal models and also with increased adherence to specific host cell types. The C. glabrata adhesin gene EPA1 is a major contributor of virulence and adherence to host cells. Here, we show that EPA1 expression is controlled by PDR1 independently of subtelomeric silencing, a known EPA1 regulation mechanism. Thus, a relationship exists between PDR1, EPA1 expression, and adherence to host cells, which is critical for efficient virulence. Our results demonstrate that acquisition of drug resistance is beneficial for C. glabrata in fungus-host relationships. These findings further highlight the challenges of the therapeutic management of C. glabrata infections in human patients

    The PACE study: past-year prevalence of tension-type headache and its subtypes in Parma's adult general population.

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    The mean global prevalence of tension-type headache (TTH) in adult is 42 %. To date, there have been no Italian studies on TTH prevalence in the adult general population. Therefore, we conducted a cross-sectional study, called PACE, aimed at detecting the prevalence of primary headaches in the city of Parma's adult general population. 904 subjects representative of Parma's adult general population were interviewed face to face by a physician of our Headache Centre. Crude past-year prevalence for definite TTH was 19.4 % (95 % CI 16.8-21.9; 18.4 %, 95 % CI 14.6-22.3 in men, and 20.1 %, 95 % CI 16.6-23.6 in women), namely, 9.0 % (95 % CI 7.1-10.8) for infrequent TTH, 9.8 % (95 % CI 7.9-11.8) for frequent TTH, and 0.6 % (95 % CI 0.1-1) for chronic TTH. Crude prevalence for probable TTH was 2.3 % (95 % CI 1.3-3.3; 2 %, 95 % CI 0.6-3.4 in men, and 2.6 %, 95 % CI 1.2-3.9 in women). Our results indicate a TTH prevalence (19.4 %) at the lower limit of data ranges for Western countries, and prevalence rates for infrequent forms (9 %) do not appear different from those of frequent forms (9.8 %)
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