44 resultados para Joint repair
Resumo:
When to allow Research Joint Ventures (RJVs) or not is an importantinstrument in the development of an optimal R&D policy. Theregulator, however, is unlikely to know all the relevant informationto regulate R&D optimally. The extent to which there existappropriability problems between the firms is one such variable thatis private information to the firms in the industry. In a duopolysetting we analyze the characteristics of a second-best R&D policywhere the government can either allow RJVs or not and give lump-sumsubsidies to the parties involved. The second-best R&D policy withoutsubsidies will either block some welfare improving RJVs or allow somewelfare reducing ones. With lump-sum subsidies, the second-best policytrades off the expected subsidy cost with allowing welfare decreasingRJVs or blocking welfare increasing ones.
Resumo:
We consider the agency problem of a staff member managing microfinancing programs, who can abuse his discretion to embezzle borrowers' repayments. The fact that most borrowers of microfinancing programs are illiterate and live in rural areas where transportation costs are very high make staff's embezzlement particularly relevant as is documented by Mknelly and Kevane (2002). We study the trade-off between the optimal rigid lending contract and the optimal discretionary one and find that a rigid contract is optimal when the audit cost is larger than gains from insurance. Our analysis explains rigid repayment schedules used by the Grameen bank as an optimal response to the bank staff's agency problem. Joint liability reduces borrowers' burden of respecting the rigid repayment schedules by providing them with partial insurance. However, the same insurance can be provided byborrowers themselves under individual liability through a side-contract.
Resumo:
The generalization of simple (two-variable) correspondence analysis to more than two categorical variables, commonly referred to as multiple correspondence analysis, is neither obvious nor well-defined. We present two alternative ways of generalizing correspondence analysis, one based on the quantification of the variables and intercorrelation relationships, and the other based on the geometric ideas of simple correspondence analysis. We propose a version of multiple correspondence analysis, with adjusted principal inertias, as the method of choice for the geometric definition, since it contains simple correspondence analysis as an exact special case, which is not the situation of the standard generalizations. We also clarify the issue of supplementary point representation and the properties of joint correspondence analysis, a method that visualizes all two-way relationships between the variables. The methodology is illustrated using data on attitudes to science from the International Social Survey Program on Environment in 1993.
Resumo:
The paper analyzes the determinants of the optimal scope of incorporation in the presenceof bankruptcy costs. Bankruptcy costs alone generate a non-trivial tradeoff between thebenefit of coinsurance and the cost of risk contamination associated to joint financing corporate projects through debt. This tradeoff is characterized for projects with binary returns,depending on the distributional characteristics of returns (mean, variability, skewness, heterogeneity, correlation, and number of projects), the bankruptcy recovery rate, and the taxrate advantage of debt relative to equity. Our testable predictions are broadly consistentwith existing empirical evidence on conglomerate mergers, spin-offs, project finance, andsecuritization.
Resumo:
Many dynamic revenue management models divide the sale period into a finite number of periods T and assume, invoking a fine-enough grid of time, that each period sees at most one booking request. These Poisson-type assumptions restrict the variability of the demand in the model, but researchers and practitioners were willing to overlook this for the benefit of tractability of the models. In this paper, we criticize this model from another angle. Estimating the discrete finite-period model poses problems of indeterminacy and non-robustness: Arbitrarily fixing T leads to arbitrary control values and on the other hand estimating T from data adds an additional layer of indeterminacy. To counter this, we first propose an alternate finite-population model that avoids this problem of fixing T and allows a wider range of demand distributions, while retaining the useful marginal-value properties of the finite-period model. The finite-population model still requires jointly estimating market size and the parameters of the customer purchase model without observing no-purchases. Estimation of market-size when no-purchases are unobservable has rarely been attempted in the marketing or revenue management literature. Indeed, we point out that it is akin to the classical statistical problem of estimating the parameters of a binomial distribution with unknown population size and success probability, and hence likely to be challenging. However, when the purchase probabilities are given by a functional form such as a multinomial-logit model, we propose an estimation heuristic that exploits the specification of the functional form, the variety of the offer sets in a typical RM setting, and qualitative knowledge of arrival rates. Finally we perform simulations to show that the estimator is very promising in obtaining unbiased estimates of population size and the model parameters.
Resumo:
Els dies 11 i 12 d'agost va tenir lloc a Copenhaguen, Dinamarca, el seminari de treball Library and Information Science Education in Europe: ¿Issues in joint curriculum development and Bologna perspectives¿. Aquest seminari, que va estar coordinat per la Royal School of Library and Information Science de Dinamarca, amb la col·laboració de l'European Association for Library and Information Education and Research (EUCLID), es va organitzar en el marc d'un projecte europeu subvencionat pel programa Sòcrates. La Facultat de Biblioteconomia i Documentació de la Universitat de Barcelona, present entre 2001 i 2005 en la Junta de Govern de l'EUCLID, va participar-hi com a soci del projecte. L'objectiu del seminari era aplegar una cinquantena d'experts europeus de l'àrea de Biblioteconomia i Documentació ¿tots ells professors d'escoles i de facultats d'universitats europees¿ per discutir qüestions relacionades amb els plans d'estudis dels ensenyaments des de la perspectiva del procés de Bolonya. El seminari consistí en dues conferències i en les reunions de treball de dotze grups formats per experts que examinaren dotze grans temes ¿prèviament acordats pels organitzadors de l'esdeveniment¿ relacionats amb els plans d'estudis d'aquells ensenyaments.
Resumo:
Repair of damaged tissue requires the coordinated action of inflammatory and tissue-specific cells to restore homeostasis, but the underlying regulatory mechanisms are poorly understood. In this paper, we report new roles for MKP-1 (mitogen-activated protein kinase [MAPK] phosphatase-1) in controlling macrophage phenotypic transitions necessary for appropriate muscle stem cell¿dependent tissue repair. By restricting p38 MAPK activation, MKP-1 allows the early pro- to antiinflammatory macrophage transition and the later progression into a macrophage exhaustion-like state characterized by cytokine silencing, thereby permitting resolution of inflammation as tissue fully recovers. p38 hyperactivation in macrophages lacking MKP-1 induced the expression of microRNA-21 (miR-21), which in turn reduced PTEN (phosphatase and tensin homologue) levels, thereby extending AKT activation. In the absence of MKP-1, p38-induced AKT activity anticipated the acquisition of the antiinflammatory gene program and final cytokine silencing in macrophages, resulting in impaired tissue healing. Such defects were reversed by temporally controlled p38 inhibition. Conversely, miR-21¿AKT interference altered homeostasis during tissue repair. This novel regulatory mechanism involving the appropriate balance of p38, MKP-1, miR-21, and AKT activities may have implications in chronic inflammatory degenerative diseases.
Resumo:
We report about a 37 year old male patient with a pectus excavatum. The patient was in NYHA functional class III. After performed computed tomography the symptoms were thought to be related to the severity of chest deformation. A Ravitch-procedure had been accomplished in a district hospital in 2009. The crack of a metal bar led to a reevaluation 2010, in which surprisingly the presence of an annuloaortic ectasia (root 73 × 74 mm) in direct neighborhood of the formerly implanted metal-bars was diagnosed. Echocardiography revealed a severe aortic valve regurgitation, the left ventricle was massively dilated presenting a reduced ejection fraction of 45%. A marfan syndrome was suspected and the patient underwent a valve sparing aortic root replacement (David procedure) in our institution with an uneventful postoperative course. A review of the literature in combination with discussion of our case suggests the application of stronger recommendations towards preoperative cardiovascular assessment in patients with pectus excavatum.
Resumo:
We propose a method to obtain a single centered correlation with use of a joint transform correlator. We analyze the required setup to carry out the whole process optically, and we also present experimental results.
Resumo:
It is possible to improve the fringe binarization method of joint transform correlation by choosing a suitable threshold level.
Resumo:
In multiobject pattern recognition the height of the correlation peaks should be controlled when the power spectrum of ajoint transform correlator is binarized. In this paper a method to predetermine the value of detection peaks is demonstrated. The technique is based on a frequency-variant threshold in order to remove the intraclass terms and on a suitable factor to normalize the binary joint power spectrum. Digital simulations and experimental hybrid implementation of this method were carried out.
Resumo:
The use of different kinds of nonlinear filtering in a joint transform correlator are studied and compared. The study is divided into two parts, one corresponding to object space and the second to the Fourier domain of the joint power spectrum. In the first part, phase and inverse filters are computed; their inverse Fourier transforms are also computed, thereby becoming the reference in the object space. In the Fourier space, the binarization of the power spectrum is realized and compared with a new procedure for removing the spatial envelope. All cases are simulated and experimentally implemented by a compact joint transform correlator.