601 research outputs found

    Common Replenishment Strategies in Supply Chain under Uncertainty Demand Environment

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    This paper is based on the model proposed by Viswanathan and continue to analyze the benefit of supply chain inventories through the use of common replenishment epochs. We studied a one-vendor, multi-buyer supply chain for a single product under uncertainty demand environment. The vendor specifies common replenishment periods and asks all buyers to replenish only at those time period and the price discount to be offered by the vendor are determined by the solution to a Stackelberg game. A numerical study is conducted to evaluate the benefit of the strategy by simulation

    Multi-Tasking vs. Screening: A Model of Academic Tenure

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    The paper develops a model of academic tenure based on multi-tasking and screening. A professor has two tasks, researching and teaching. We assume that researching performance is easy to measure but teaching performance is immeasurable. Then Holmtrom and Milgrom's (1991) classical muli-task principal-agent model implies that the only way for the the university to "incentivize" teaching activity is decreasing the incentive power to researching activity. This justifies the low-powered contract to tenured professors. However, with low-powered contract, the university will face serious informational problem in the process of enrollment, either transferring rents to the candidates with low ability if the wage level is high, or suffering from the potential occupational vacancy if the wage level is low. To this dilemma, the up-or-out contract is a possible solution

    Multi-Tasking vs. Screening: A Model of Academic Tenure

    Get PDF
    The paper develops a model of academic tenure based on multi-tasking and screening. A professor has two tasks, researching and teaching. We assume that researching performance is easy to measure but teaching performance is immeasurable. Then Holmtrom and Milgrom's (1991) classical muli-task principal-agent model implies that the only way for the the university to "incentivize" teaching activity is decreasing the incentive power to researching activity. This justifies the low-powered contract to tenured professors. However, with low-powered contract, the university will face serious informational problem in the process of enrollment, either transferring rents to the candidates with low ability if the wage level is high, or suffering from the potential occupational vacancy if the wage level is low. To this dilemma, the up-or-out contract is a possible solution

    Bounded Confidence Evolution of Opinions and Actions in Social Networks

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    This work was supported in part by the National Natural Science Foundation of China under Grant 71991460, Grant 71991465, Grant 71871149, Grant 71910107002, and Grant 71725001; in part by the Research Foundation of Education Bureau of Hunan Province, China, under Grant 20B147; and in part by the Spanish State Research Agency under Project PID2019-103880RB-I00/AEI/10.13039/501100011033.Inspired by the continuous opinion and discrete action (CODA) model, bounded confidence and social networks, the bounded confidence evolution of opinions and actions in social networks is investigated and a social network opinions and actions evolutions (SNOAEs) model is proposed. In the SNOAE model, it is assumed that each agent has a CODA for a certain issue. Agents’ opinions are private and invisible, that is, an individual agent only knows its own opinion and cannot obtain other agents’ opinions unless there is a social network connection edge that allows their communication; agents’ actions are public and visible to all agents and impact other agents’ actions. Opinions and actions evolve in a directed social network. In the limitation of the bounded confidence, other agents’ actions or agents’ opinions noticed or obtained by network communication, respectively, are used by agents to update their opinions. Based on the SNOAE model, the evolution of the opinions and actions with bounded confidence is investigated in social networks both theoretically and experimentally with a detailed simulation analysis. Theoretical research results show that discrete actions can attract agents who trust the discrete action, and make agents to express extreme opinions. Simulation experiments results show that social network connection probability, bounded confidence, and the opinion threshold of action choice parameters have strong impacts on the evolution of opinions and actions. However, the number of agents in the social network has no obvious influence on the evolution of opinions and actions.National Natural Science Foundation of China (NSFC) 71991460 71991465 71871149 71910107002 71725001Research Foundation of Education Bureau of Hunan Province, China 20B147Spanish Government PID2019-103880RB-I00/AEI/10.13039/50110001103

    Induction of HSPA4 and HSPA14 by NBS1 overexpression contributes to NBS1-induced in vitro metastatic and transformation activity

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    <p>Abstract</p> <p>Background</p> <p>Nijmegen breakage syndrome (NBS) is a chromosomal-instability syndrome associated with cancer predisposition, radiosensitivity, microcephaly, and growth retardation. The NBS gene product, NBS1 (p95) or nibrin, is a part of the MRN complex, a central player associated with double-strand break (DSB) repair. We previously demonstrated that NBS1 overexpression contributes to transformation through the activation of PI 3-kinase/Akt. NBS1 overexpression also induces epithelial-mesenchymal transition through the Snail/MMP2 pathway.</p> <p>Methods</p> <p>RT-PCR, Western blot analysis, <it>in vitro </it>migration/invasion, soft agar colony formation, and gelatin zymography assays were performed.</p> <p>Results</p> <p>Here we show that heat shock protein family members, A4 and A14, were induced by NBS1 overexpression. siRNA mediated knockdown of HSPA4 or HSPA14 decreased the <it>in vitro </it>migration, invasion, and transformation activity in H1299 cells overexpressing NBS1. However, HSPA4 or HSPA14 induced activity was not mediated through MMP2. NBS1 overexpression induced the expression of heat shock transcription factor 4b (HSF4b), which correlated with the expression of HSPA4 and HSPA14.</p> <p>Conclusion</p> <p>These results identify a novel pathway (NBS1-HSF4b-HSPA4/HSPA14 axis) to induce migration, invasion, and transformation, suggesting the activation of multiple signaling events induced by NBS1 overexpression.</p

    catena-Poly[[[[N′-(4-cyano­benzyl­idene)nicotinohydrazide]silver(I)]-μ-[N′-4-cyano­benzyl­idene)nicotinohydrazide]] hexa­fluoridoarsenate]

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    In the title compound, {[Ag(C14H10N4O)2]AsF6}n, the AgI ion is coordinated by two N atoms from two different pyridyl rings and one N atom from one carbonitrile group of three different N′-(4-cyano­benzyl­idene)nicotinohydrazide ligands in a distorted T-shaped geometry. The Ag—Ncarbonitrile bond distance is significant longer than those of Ag—Npyrid­yl. The bond angles around the AgI atom are also not in line with those in an ideal T-shaped geometry. One type of ligand acts as the bridge that connects AgI atoms into chains along [01]. These chains are linked to each other via N—H⋯O hydrogen bonds and Ag⋯O inter­actions with an Ag⋯O separation of 2.869 (2) Å. In addition, the [AsF6]− counter-anions are linked to the hydrazone groups through N—H⋯F hydrogen bonds. Four of the F atoms of the [AsF6]− anion are disordered over two sets of sites with occupancies of 0.732 (9) and 0.268 (9)

    catena-Poly[[[diaqua­bis(2-methyl-6-oxo-1,6-dihydro-3,4′-bipyridine-5-carbo­nitrile)copper(II)]-μ-sulfato] tetra­hydrate]

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    In the title polymer, {[Cu(SO4)(C12H9N3O)2(H2O)2]·4H2O}n, both the metal center and the sulfate anion are located on a twofold axis. The CuII ion is coordinated by two pyridyl N atoms from two symmetry-related organic ligands, two O atoms from two symmetry-related water mol­ecules, and two O atoms from two symmetry-related sulfate anions, resulting in a distorted octa­hedral geometry. The sulfate anions act as μ2-bridges and connect metal ions, forming a one-dimensional chain along the b axis. The three-dimensional crystal structure is established through inter­molecular N—H⋯O and O—H⋯O hydrogen bonds involving the organic ligands, sulfate anions, coordinated and uncoordinated water mol­ecules, and through π–π inter­acting 2-pyridone rings, with centroid–centroid separations of ca 3.96 Å and tilt angles of ca 2.62°
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