103 research outputs found

    Managing Price Uncertainty in Prosumer-Centric Energy Trading: A Prospect-Theoretic Stackelberg Game Approach

    Full text link
    In this paper, the problem of energy trading between smart grid prosumers, who can simultaneously consume and produce energy, and a grid power company is studied. The problem is formulated as a single-leader, multiple-follower Stackelberg game between the power company and multiple prosumers. In this game, the power company acts as a leader who determines the pricing strategy that maximizes its profits, while the prosumers act as followers who react by choosing the amount of energy to buy or sell so as to optimize their current and future profits. The proposed game accounts for each prosumer's subjective decision when faced with the uncertainty of profits, induced by the random future price. In particular, the framing effect, from the framework of prospect theory (PT), is used to account for each prosumer's valuation of its gains and losses with respect to an individual utility reference point. The reference point changes between prosumers and stems from their past experience and future aspirations of profits. The followers' noncooperative game is shown to admit a unique pure-strategy Nash equilibrium (NE) under classical game theory (CGT) which is obtained using a fully distributed algorithm. The results are extended to account for the case of PT using algorithmic solutions that can achieve an NE under certain conditions. Simulation results show that the total grid load varies significantly with the prosumers' reference point and their loss-aversion level. In addition, it is shown that the power company's profits considerably decrease when it fails to account for the prosumers' subjective perceptions under PT

    Two novel hexadepsipeptides with several modified amino acid residues isolated from the fungus isaria

    Get PDF
    Two new cyclohexadepsipeptides have been isolated from the fungus Isaria. Fungal growth in solid media yielded hyphal strands from which peptide fractions were readily isolable by organic-solvent extraction. Two novel cyclodepsipeptides, isaridin A and isaridin B, have been isolated by reverse-phase HPLC, and characterized by ESI-MS and 1H-NMR. Single crystals of both peptides have been obtained, and their 3D structures were elucidated by X-ray diffraction. The isaridins contain several unusual amino acid residues. The sequences are cyclo(β-Gly-HyLeu-Pro-Phe-NMeVal-NMePhe) and cyclo(β-Gly-HyLeu-β-MePro-Phe-NMeVal-NMePhe), where NMeVal is N-methylvaline, NMePhe N-methylphenylalanine, and HyLeu hydroxyleucine (=2-hydroxy-4-methylpentanoic acid). The two peptides differ from one another at residue 3, isaridin A having an (S)-proline at this position, while β-methyl-(S)-proline (=(2S,3S)-2,3,4,5-tetrahydro-3-methyl-1H-pyrrole-2-carboxylic acid) is found in isaridin B. The solid-state conformations of both cyclic depsipeptides are characterized by the presence of two cis peptide bonds at HyLeu(2)-Pro(3)/HyLeu(2)-β-MePro(3) and NMeVal(5)-NMePhe(6), respectively. In isaridin A, a strong intramolecular H-bond is observed between Phe(4)CO...HNβ-Gly(1), and a similar, but weaker, interaction is observed between β-Gly(1)COHNPhe(4). In contrast, in isaridin B, only a single intramolecular H-bond is observed between β-Gly(1)CO...HNPhe(4)

    Evidence of Nickel and Other Trace Elements and Their Relationship to Clinical Findings in Acute Mesoamerican Nephropathy: A Case-Control Analysis

    Get PDF
    BACKGROUND: Although there are several hypothesized etiologies of Mesoamerican Nephropathy (MeN), evidence has not yet pointed to the underlying cause. Exposure to various trace elements can cause the clinical features observed in MeN. METHODS AND FINDINGS: We measured 15 trace elements, including heavy metals, in renal case-patients (n = 18) and healthy controls (n = 36) in a MeN high-risk region of Nicaragua. Toenails clippings from study participants were analyzed using inductively coupled plasma mass spectrometry. A case-control analysis was performed, and concentrations were also analyzed over participant characteristics and clinical parameters. Nickel (Ni) concentrations were significantly higher in toenails from cases (1.554 mg/kg [0.176–42.647]) than controls (0.208 mg/kg [0.055–51.235]; p \u3c 0.001). Ni concentrations correlated positively with serum creatinine levels (p = 0.001) and negatively with eGFR (p = 0.001). Greater Ni exposure was also associated with higher leukocyte (p = 0.001) and neutrophil (p = 0.003) counts, fewer lymphocytes (p = 0.003), and lower hemoglobin (p = 0.004) and hematocrit (p = 0.011). CONCLUSIONS: Low-dose, chronic environmental exposure to Ni is a possible health risk in this setting. Ni intoxication and resulting systemic and renal effects could explain the clinical signs observed during early MeN. This study provides compelling evidence for a role of Ni in the acute renal impairment observed in this MeN high-risk population. Additional work to assess exposure levels in a larger and heterogeneous population, identify environmental sources of Ni and exposure pathways, and evaluate the link between Ni and MeN pathogenesis are urgently needed

    Establishing Core Outcome Domains in Hemodialysis: Report of the Standardized Outcomes in Nephrology-Hemodialysis (SONG-HD) Consensus Workshop

    Get PDF
    Evidence-informed decision making in clinical care and policy in nephrology is undermined by trials that selectively report a large number of heterogeneous outcomes, many of which are not patient centered. The Standardized Outcomes in Nephrology-Hemodialysis (SONG-HD) Initiative convened an international consensus workshop on November 7, 2015, to discuss the identification and implementation of a potential core outcome set for all trials in hemodialysis. The purpose of this article is to report qualitative analyses of the workshop discussions, describing the key aspects to consider when establishing core outcomes in trials involving patients on hemodialysis therapy. Key stakeholders including 8 patients/caregivers and 47 health professionals (nephrologists, policymakers, industry, and researchers) attended the workshop. Attendees suggested that identifying core outcomes required equitable stakeholder engagement to ensure relevance across patient populations, flexibility to consider evolving priorities over time, deconstruction of language and meaning for conceptual consistency and clarity, understanding of potential overlap and associations between outcomes, and an assessment of applicability to the range of interventions in hemodialysis. For implementation, they proposed that core outcomes must have simple, inexpensive, and validated outcome measures that could be used in clinical care (quality indicators) and trials (including pragmatic trials) and endorsement by regulatory agencies. Integrating these recommendations may foster acceptance and optimize the uptake and translation of core outcomes in hemodialysis, leading to more informative research, for better treatment and improved patient outcomes

    Developing a Set of Core Outcomes for Trials in Haemodialysis: An International Delphi Survey

    Get PDF
    AIM: To generate a consensus-based, prioritized list of core outcomes for trials in haemodialysis. BACKGROUND: Survival and quality of life for patients on haemodialysis remain poor despite substantial research efforts. Existing trials often report surrogate outcomes that may not be relevant to patients and clinicians. A core outcome set that reflects stakeholder priorities would improve the relevance, efficiency, and comparability of haemodialysis trials. METHODS: In an online Delphi survey, participants rated the importance of outcomes using a 9-point Likert scale. In Round 2 and 3, participants reviewed the scores and comments of other respondents and re-rated the outcomes. For each outcome, we calculated the median, mean, and proportion rating 7-9 (“critically important”). RESULTS: 1,181 participants (202 [17%] patients/caregivers, 979 health professionals) from 73 countries completed Round 1 and 838 (150 [18%] patients/caregivers) completed Round 3 (71% response rate). Outcomes achieving consensus as high priorities across both groups were: vascular access complications, cardiovascular disease, mortality, dialysis adequacy and fatigue. Patients/caregivers rated four outcomes higher than health professionals: ability to travel (mean difference 0.9), dialysis-free time (0.5), dialysis adequacy (0.3), and washed out after dialysis (0.2). Health professionals rated 11 outcomes higher: mortality (1.0), hospitalization (1.0), drop in blood pressure (1.0), vascular access complications (0.9), depression (0.9), cardiovascular disease (0.8), target weight (0.7), infection (0.4), potassium (0.4), ability to work (0.3), and pain (0.3). CONCLUSIONS: The top stakeholder prioritized outcomes were vascular access problems, cardiovascular disease, mortality, dialysis adequacy and fatigue. Patients/caregivers gave higher priority to lifestyle-related outcomes than health professionals. This prioritized set of outcomes can inform the establishment of a core outcome set, to improve the value of trial evidence to support decision-making for people on haemodialysis
    • …
    corecore