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11.
In new institutional economics, the variance in institutions explains differences in cross-country output per capita. Institutions may also explain how the supply of oil is affected within oil-producing countries. For example in the early 1970s, as nominal oil prices increased from $3 per barrel to $11 per barrel, a number of OPEC oil producers changed the institutional environment by nationalizing their oil production and putting under government control all petroleum-related capital and infrastructure. This affected oil supplies. Similar institutional changes may be happening again now that oil prices are rising. In particular, the newly democratic Russia may be following the same path. The Russian government has already effectively taken over control of much of the oil production capacity in the country and is still heavily involved in natural gas production. In this paper, we will look at the Russian upstream oil industry as it changed from central planning to a market-oriented sector and is now swaying toward re-nationalization. Some of the laws and institutional transitions will be detailed in order to elucidate what has taken place.  相似文献   
12.
In this paper is presented an algorithm for constructing natural deduction proofs in the propositional intuitionistic and classical logics according to the analogy relating intuitionistic propositional formulas and natural deduction proofs, respectively, to types and terms of simple type theory. Proofs are constructed as closed terms in the simple typed calculus. The soundness and completeness of this method are proved.  相似文献   
13.
Cancer-associated fibroblasts (CAFs) are one of the most abundant and critical components of the tumor stroma. CAFs can impact many important steps of cancerogenesis and may also influence treatment resistance. Some of these effects need the direct contact of CAFs and cancer cells, while some involve paracrine signals. In this study, we investigated the ability of head and neck squamous cell carcinomas (HNSCC) patient-derived CAFs to promote or inhibit the colony-forming ability of HNSCC cells. The effect of cisplatin on this promoting or inhibiting influence was also studied. The subsequent analysis focused on changes in the expression of genes associated with cancer progression. We found that cisplatin response in model HNSCC cancer cells was modified by coculture with CAFs, was CAF-specific, and different patient-derived CAFs had a different “sensitizing ratio”. Increased expression of VEGFA, PGE2S, COX2, EGFR, and NANOG in cancer cells was characteristic for the increase of resistance. On the other hand, CCL2 expression was associated with sensitizing effect. Significantly higher amounts of cisplatin were found in CAFs derived from patients who subsequently experienced a recurrence. In conclusion, our results showed that CAFs could promote and/or inhibit colony-forming capability and cisplatin resistance in HNSCC cells via paracrine effects and subsequent changes in gene expression of cancer-associated genes in cancer cells.  相似文献   
14.
Mastocytosis is characterized by the pathological accumulation of mast cells (MC) in various organs. In these patients, MC may degranulate and thereby contribute to clinical symptoms, especially when a concomitant allergy is present. However, MC activation can not only be induced by high-affinity receptors for IgE, but also by anaphylatoxins, neuropeptides, IgG immune complexes, complement-components, drugs, products of bacteria or parasites, as well as physical factors such as heat, cold, vibration, stress, sun, or physical effort. Symptoms due to mediators released by activated MC may develop in adults suffering from systemic mastocytosis, but also evolve in children who usually have cutaneous mastocytosis (CM). Clinically, CM is otherwise characterized by typical brown, maculopapular skin lesions or mastocytoma associated with a positive Darier’s sign. Pruritus and flushing are common and blistering may also be recorded, especially in diffuse CM (DCM). Pediatric patients with mastocytosis may also have gastrointestinal, respiratory, and neurologic complaints. Although anaphylaxis is not a typical finding, pediatric patients with massive skin involvement and high tryptase levels have a relatively high risk to develop anaphylaxis. This paper reviews MC mediator-related symptoms and anaphylaxis in children with mastocytosis, with special emphasis on risk factors, triggers, and management.  相似文献   
15.
Leptin is an adipokine that regulates appetite and body mass and has many other pleiotropic functions, including regulating kidney function. Increased evidence shows that chronic kidney disease (CKD) is associated with hyperleptinemia, but the reasons for this phenomenon are not fully understood. In this review, we focused on potential causes of hyperleptinemia in patients with CKD and the effects of elevated serum leptin levels on patient kidney function and cardiovascular risk. The available data indicate that the increased concentration of leptin in the blood of CKD patients may result from both decreased leptin elimination from the circulation by the kidneys (due to renal dysfunction) and increased leptin production by the adipose tissue. The overproduction of leptin by the adipose tissue could result from: (a) hyperinsulinemia; (b) chronic inflammation; and (c) significant lipid disturbances in CKD patients. Elevated leptin in CKD patients may further deteriorate kidney function and lead to increased cardiovascular risk.  相似文献   
16.
In this paper, we continue the research on formal treatment of attributes of information, based on the computational approach. In this scenario, the usefulness of advisory information is measured by the decrease in complexity of a problem we need to solve. We propose to model the time criticality via usefulness of a piece of information which is received during the computation. As a modeling tool, we use deterministic finite automata.  相似文献   
17.
The characterization of thin, selectively imprinted films of nylon‐6 was performed. Amino acids were used as template molecules. Spin‐cast films were prepared with sizes ranging from 2 μm to 300 nm, depending on the nylon and template concentration in the casting solution. The morphological characteristics of the film surface were examined by atomic force microscopy, and the structure within the films was observed by freeze‐fracture scanning electron microscopy. The film activity was clearly coordinated with the appearance of nanometer‐sized pores both on the surface and within the film. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2919–2926, 2006  相似文献   
18.
Threats on the stability of a financial system may severely affect the functioning of the entire economy, and thus considerable emphasis is placed on the analyzing the cause and effect of such threats. The financial crisis in the current and past decade has shown that one important cause of instability in global markets is the so-called financial contagion, namely the spreadings of instabilities or failures of individual components of the network to other, perhaps healthier, components. This leads to a natural question of whether the regulatory authorities could have predicted and perhaps mitigated the current economic crisis by effective computations of some stability measure of the banking networks. Motivated by such observations, we consider the problem of defining and evaluating stabilities of both homogeneous and heterogeneous banking networks against propagation of synchronous idiosyncratic shocks given to a subset of banks. We formalize the homogeneous banking network model of Nier et al. (J. Econ. Dyn. Control 31:2033–2060, 2007) and its corresponding heterogeneous version, formalize the synchronous shock propagation procedures outlined in (Nier et al. J. Econ. Dyn. Control 31:2033–2060, 2007; M. Eboli Mimeo, 2004), define two appropriate stability measures and investigate the computational complexities of evaluating these measures for various network topologies and parameters of interest. Our results and proofs also shed some light on the properties of topologies and parameters of the network that may lead to higher or lower stabilities.  相似文献   
19.
Marek  J.  Mohyla  I.  Kos  J.  Krček  M. 《Journal of Applied Electrochemistry》1979,9(1):89-100
Sintered negative electrodes for nickel-cadmium secondary cells were studied. Model electrodes prepared by means of three different impregnation methods were evaluated. It was demonstrated that the impregnation procedure may affect properties of active mass and the service life of electrodes in a significant way.  相似文献   
20.
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