Lead halide perovskites are the new rising generation of semiconductor materials due to their unique optical and electrical properties. The investigation of the interaction of halide perovskites and light is a key issue not only for understanding their photophysics but also for practical applications. Hence, tremendous efforts have been devoted to this topic and brunch into two: (i) decomposition of the halide perovskites thin films under light illumination; and (ii) influence of light soaking on their photoluminescence (PL) properties. In this review, we for the first time thoroughly compare the illumination conditions and the sample environment to correlate the PL changes and decomposition of perovskite under light illumination. In the case of vacuum and dry nitrogen, PL of the halide perovskite (MAPbI3–xClx, MAPbBr3–xClx, MAPbI3) thin films decreases due to the defects induced by light illumination, and under high excitations, the thin film even decomposes. In the presence of oxygen or moisture, light induces the PL enhancement of halide perovskite (MAPbI3) thin films at low light illumination, while increasing the excitation, which causes the PL to quench and perovskite thin film to decompose. In the case of mixed halide perovskite ((MA)Pb(BrxI1-x)3) light induces reversible segregation of Br domains and I domains.
Major spices crops such as black pepper (Piper nigrum L.), cardamom (Elettaria cardamomum Maton.) and turmeric (Curcuma longa L.) production in India, is sustained losses due to several reasons. Among them, one of the major constraints are nematode infesting diseases, which causes significant yield losses and affecting their productivity. The major nematode pests infesting these crops include burrowing nematode Radopholus similis; root knot nematode, Meloidogyne incognita and M. javanica on black pepper. Whereas, lesion nematode, Pratylenchus sp., M. incognita and R. similis infesting cardamom and turmeric crops. Black pepper is susceptible to a number of diseases of which slow decline caused by R. similis and M. incognita or Phytophthora capsici either alone and in combination and root knot disease caused by Meloidogyne spp. are the major ones. Root knot disease caused by Meloidogyne spp. is major constraints in the successful cultivation and production in cardamom. Turmeric is susceptible to a number of diseases such as brown rot disease is caused by Fusarium sp. and lesion nematode, Pratylenchus sp. and root knot disease caused by M. incognita. Adoption of integrated pest management schedules is important in these crops since excessive use of pesticides could lead to pesticide residues in the produce affecting human health and also causing other ecological hazards.
Public-Private Partnerships (PPPs) can be an effective way of delivering infrastructure. However, achieving value for money can be difficult if government agencies are not equipped to manage them effectively. Experience from OECD countries shows that the availability of finance is not the main obstacle in delivering infrastructure. Governance—effective decision-making—is the most influential aspect on the quality of an investment, including PPP investments. In 2012, the OECD together with its member countries developed principles to ensure that PPPs deliver value for money transparently and prudently, supported by the right institutional capacities and processes to harness the upside of PPPs without jeopardizing fiscal sustainability. Survey results from OECD countries show that some dimensions of the recommended practices are well applied and past and ongoing reforms show progress. However, other principles have not been well implemented, reflecting the continuing need for improving public governance of PPPs across countries.
There is a large literature on public-private-partnership, covering many different areas and aspects. This article deals with a specific but important aspect: the decision-making mechanisms to choose the management of PPP enterprises. In this sector, a suitable choice of managers is of particular importance because the persons chosen must balance the public and private interests. This is often difficult to achieve. Two new procedures are discussed, “Directed Random Choice” and “Rotating CEOs”. In each case, the advantages and disadvantages of the procedure of choosing the managers of PPP enterprises are discussed and evaluated. It is concluded that the two novel mechanisms should be seriously considered when choosing the managers of PPP enterprises.
Starting from the ‘90s, there has been a significant increase in PPP use in the public sector in Europe, benefiting the implementation of infrastructure projects. In Italy, PPP is still much more limited than in such countries as the UK and France: the projects funded are smaller and the sectors involved are less appropriate. Based on the economic literature, European initiatives and international comparisons, the paper examines aspects of regulations that could encourage the appropriate use of PPP and considers the problems with the Italian regulations, while proposing some corrective measures. The main limitations involve: i) the absence of adequate preliminary assessments about the advantages of using PPP rather than the traditional procurement, ii) the relative lack of attention to the contract terms, iii) inadequate safeguards to ensure the bankability of the projects, and iv) limited information transparency and accessibility.
This paper uses Public Choice analysis to examine the case for and experience with Public-Private Partnerships (PPPs). A PPP is a contractual platform which connects a governmental body and a private entity. The goal is to provide a public sector program, service, or asset that would normally be provided exclusively by a public sector entity. This paper focuses on PPPs in developed countries, but it also draws on studies of PPPs in developing countries. The economics literature generally defines PPPs as long-term contractual arrangements between a public authority (local or central government) and a private supplier for the delivery of services. The private sector supplier takes responsibility for building infrastructure components, securing financing of the investment, and then managing and maintaining this facility.
However, in addition to those formed through contracts, PPPs may take other forms such as those developed in response to tax subvention or coercion, as in the case of regulatory mandates. A key element of PPP is that the private partner takes on a significant portion of the risk through a schedule of specified remuneration, contingency payments, and provision for dispute resolution. PPPs typically are long-term arrangements and involve large corporations on the private side, but may also be limited to specific phases of a project.
The types of PPPs discussed in this paper exclude arrangements which may result from government mandates such as the statutory emission mandates imposed on automobile manufacturers and industrial facilities (e.g., power plants). It also excludes PPP-like organizations resulting from US section 501(c)(3) of the Internal Revenue Code, which provides tax subsidies for certain public charities, scientific research organizations, and organizations whose goals are to prevent cruelty to animals or erect public monuments at no expense to the government. This paper concludes that an array of Public Choice tools are applicable to understanding the emergence, success, or failure of PPPs. Several short case studies are provided to illustrate the practicalities of PPPs.
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