120 research outputs found

    Analysis of two-player quantum games in an EPR setting using geometric algebra

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    The framework for playing quantum games in an Einstein-Podolsky-Rosen (EPR) type setting is investigated using the mathematical formalism of Clifford geometric algebra (GA). In this setting, the players' strategy sets remain identical to the ones in the classical mixed-strategy version of the game, which is then obtained as proper subset of the corresponding quantum game. As examples, using GA we analyze the games of Prisoners' Dilemma and Stag Hunt when played in the EPR type setting.Comment: 20 pages, no figure, revise

    N-player quantum games in an EPR setting

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    The NN-player quantum game is analyzed in the context of an Einstein-Podolsky-Rosen (EPR) experiment. In this setting, a player's strategies are not unitary transformations as in alternate quantum game-theoretic frameworks, but a classical choice between two directions along which spin or polarization measurements are made. The players' strategies thus remain identical to their strategies in the mixed-strategy version of the classical game. In the EPR setting the quantum game reduces itself to the corresponding classical game when the shared quantum state reaches zero entanglement. We find the relations for the probability distribution for NN-qubit GHZ and W-type states, subject to general measurement directions, from which the expressions for the mixed Nash equilibrium and the payoffs are determined. Players' payoffs are then defined with linear functions so that common two-player games can be easily extended to the NN-player case and permit analytic expressions for the Nash equilibrium. As a specific example, we solve the Prisoners' Dilemma game for general N2 N \ge 2 . We find a new property for the game that for an even number of players the payoffs at the Nash equilibrium are equal, whereas for an odd number of players the cooperating players receive higher payoffs.Comment: 26 pages, 2 figure

    Temperature, recreational fishing and diapause egg connections : dispersal of spiny water fleas (Bythotrephes longimanus)

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    © The Author(s), 2011. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License. The definitive version was published in Biological Invasions 13 (2011): 2513-2531, doi:10.1007/s10530-011-0078-8.The spiny water flea (Bythotrephes longimanus) is spreading from Great Lakes coastal waters into northern inland lakes within a northern temperature-defined latitudinal band. Colonization of Great Lakes coastal embayments is assisted by winds and seiche surges, yet rapid inland expansion across the northern states comes through an overland process. The lack of invasions at Isle Royale National Park contrasts with rapid expansion on the nearby Keweenaw Peninsula. Both regions have comparable geology, lake density, and fauna, but differ in recreational fishing boat access, visitation, and containment measures. Tail spines protect Bythotrephes against young of the year, but not larger fish, yet the unusual thick-shelled diapausing eggs can pass through fish guts in viable condition. Sediment traps illustrate how fish spread diapausing eggs across lakes in fecal pellets. Trillions of diapausing eggs are produced per year in Lake Michigan and billions per year in Lake Michigamme, a large inland lake. Dispersal by recreational fishing is linked to use of baitfish, diapausing eggs defecated into live wells and bait buckets, and Bythothephes snagged on fishing line, anchor ropes, and minnow seines. Relatively simple measures, such as on-site rinsing of live wells, restricting transfer of certain baitfish species, or holding baitfish for 24 h (defecation period), should greatly reduce dispersal.Study of Lakes Superior and Michigan was funded from NSF OCE-9726680 and OCE-9712872 to W.C.K., OCE-9712889 to J. Churchill. Geographic survey sampling and Park studies in the national parks during 2008-2010 were funded by a grant from the National Park Service Natural Resource Preservation Program GLNF CESU Task Agreement No. J6067080012

    31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

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    Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival

    Differing effects of suspended sediment on the performance of native and exotic Daphnia

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    Although large cladocerans are usually uncommon in large rivers, Daphnia lumholtzi (an exotic species in North America) is widespread and occasionally abundant. We collected zooplankton on the Illinois River (Illinois, U.S.A.) in 1995 and 1996 and found that the peak density of D. lumholtzi (25 L1) typically exceeded that of all native species combined. Maximum density occurred during warm periods (up to 27°C) when concentrations of inorganic suspended sediments were high (\u3e50mg L-1). Using a life table experiment, we examined the effects of variation in suspended sediment (0 and 80mg L-1) and food (104 and 105 Ankistrodesmus cells mL-1) on fitness of D. lumholtzi and the native Daphnia parvula. Daphnia lumholtzi had greater survivorship than D. parvula in most treatments and higher life‐time fertility than D. parvula in all treatments. Both species achieved their fastest intrinsic rates of growth in treatments with high food, but their responses to suspended solids differed. The growth rate of D. lumholtzi in high food was slightly increased by higher turbidity, whereas that of D. parvula was depressed. Results suggest that the ability of D. lumholtzi to tolerate suspended solids is an important factor contributing to its success in invading North American rivers

    Adiponectin May Modify the Risk of Barrett's Esophagus in Patients With Gastroesophageal Reflux Disease.

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    Background &amp; aimsAbdominal obesity and increasing body mass index are risk factors for esophageal adenocarcinoma and its main precursor, Barrett's esophagus; however, there are no known biological mechanisms for these associations or regarding why only some patients with gastroesophageal reflux disease develop Barrett's esophagus. We evaluated the association between Barrett's esophagus and multimers of an adipose-associated hormone, adiponectin.MethodsWe conducted a case-control study evaluating the associations between adiponectin (total, high-molecular-weight, and low-/medium-molecular-weight) and Barrett's esophagus within the Kaiser Permanente Northern California population. Patients with a new diagnosis of Barrett's esophagus (cases) were matched to patients with gastroesophageal reflux disease (GERD) without Barrett's esophagus and to population controls.ResultsComplete serologic and epidemiologic data were available for 284 cases, 294 GERD controls, and 285 population controls. Increasing adiponectin levels were a risk factor for Barrett's esophagus among patients with GERD (total adiponectin fourth vs first quartile odds ratio [OR], 1.96; 95% confidence interval [CI], 1.17-3.27; high-molecular-weight adiponectin OR, 1.65; 95% CI, 1.00-2.73; low-/medium-molecular-weight adiponectin OR, 2.18; 95% CI, 1.33-3.56), but not compared with population controls. The associations were significantly stronger among patients reporting frequent GERD symptoms and among smokers (P values interaction &lt; .01).ConclusionsAdiponectin levels are associated positively with the risk of Barrett's esophagus among patients with GERD and among smokers, but not among population controls without GERD symptoms. Higher adiponectin concentrations either independently may contribute to the aberrant healing of esophageal injury into Barrett's esophagus or be a marker for other factors
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