retention level
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2021 ◽  
Vol 4 ◽  
Author(s):  
Jessica I. Zugic ◽  
Michael F. J. Pisaric ◽  
Shawn M. McKenzie ◽  
William C. Parker ◽  
Ken A. Elliott ◽  
...  

As atmospheric carbon dioxide concentrations continue to rise and global temperatures increase, there is growing concern about the sustainability, health, and carbon sequestration potential of forest ecosystems. Variable retention harvesting (VRH) has been suggested to be a potential method to increase forest biodiversity, growth, and carbon (C) sequestration. A field trial was established in an 88-year-old red pine (Pinus resinosa Ait.) plantation in southern Ontario, Canada, using a completely randomized design to examine the response of tree productivity and other forest values to five harvesting treatments: 33% aggregate retention (33A), 55% aggregate retention (55A), 33% dispersed retention (33D), and 55% dispersed retention (55D) in comparison to an unharvested control (CN). In this study, we explored the impacts of VRH on aboveground stem radial growth and annual C increment. Standard dendrochronological methods and allometric equations were used to quantify tree- and stand-level treatment effects during a five-year pre-harvest (2009–2013) and post-harvest (2014–2018) period. Tree-level growth and C increment were increased by the dispersed retention pattern regardless of retention level. At the stand level, the total C increment was highest at greater retention levels and did not vary with retention pattern. These results suggest that the choice of retention level and pattern can have a large influence on management objectives as they relate to timber production, climate change adaptation, and/or climate change mitigation.


Author(s):  
V. I. Vyshnevskyi ◽  
V. V. Demianov

The relevance of research is the lack of actual parameters of the Dnipro Сascade.  The purpose and objectives of the study are to specify the actual parameters of the Kamianske Reservoir, which is the part of the Dnipro Cascade. Methods and techniques. The study was based on using the actual Navigation map of the Kamianske Reservoir. The available data were processed when using AutoCAD program. The satellite images were used as well. Results and main conclusions. It was identified that the main parameters of the Kamianske Reservoir, which is the part of the Dnipro Cascade, significantly differ from those obtained earlier, in particular, which are given in the operation rules of the Dnipro Сascade. The most important parameters of the Kamianske Reservoir to keep normal retention level (64.0 m) are as follows: water area (water surface) – 537 km2, total volume – 2636 million m3, useful storage capacity – 495 million m3. A small increase in the total volume compared to the project one is supposed to be the result of significant extraction of construction raw materials from the bottom of the reservoir. The reservoir length, depending on the ways of measuring, varies from 119 to 137 km. It was determined that the actual maximum depth of the reservoir (23 m) is significantly larger than it is indicated in reference books. The actual average depth of 5.8 m is significantly larger as well. Some parameters of the reservoir, which were previously ignored by researchers, are given as a result of the study. This parameter, in particular, is the area of the islands, which is 48.9 km2. The area of shallow water with depths less than 2 m is 152.4 km2. This area is mainly located in the upper and middle parts of the reservoir – mainly near the left bank. An important parameter is the cross section of the central reach of the reservoir, where the main movement of water is observed. Depending on the length of the reservoir, this cross-section varies in the range of 17,900–20,600 m2. The smallest cross-section is a characteristic feature of the upper part of the reservoir that causes an increase in flow velocity above 1.0 m/sec. It was concluded that the existing operation rules of the Dnipro Сascade does not correspond to the present and require the radical improvement. A mandatory requirement for the new rules is specifying the modern parameters of the reservoirs, built on the Dnipro River. Perspectives. There is need to specify the parameters of all reservoirs of the Dnipro Сascade. It is a basis for the development of new operation rules for the Dnipro Сascade.


2021 ◽  
Vol 1 (5) ◽  
Author(s):  
Alberto Bettanti ◽  
Antonella Lanati

AbstractIn broad terms, risk management (RM) covers four conventional actions in addressing operational risks (OpRisks), i.e., actions to mitigate, eliminate, accept, and transfer operational risks. In relation to transferring OpRisks to external third parties, this study aids chief risk officers (CROs) in addressing issues related to the reduction of economic exposure to OpRisk. In this respect, the economic handling of OpRisks and their coverage through specific insurance programs are among the major challenges that CROs face within their roles. The aim of this paper is to provide CROs with an analytical pathway to addressing these challenges by applying the total cost of risk (TCoR) method tailored to their purposes. Through a leading example, this paper demonstrates that the TCoR approach meaningfully and productively supports CROs’ decisions when striving to deal with OpRisk. In fact, the TCoR approach implementation, together with the application of Monte Carlo simulation as a computational tool, drives TCoR value optimization when OpRisk is transferred to insurance agencies. In addition, by applying a TCoR framework, CROs can find the correct and cost-effective balance between the company’s retention level—consistent with the company’s risk appetite—and the premiums paid to insurance agencies. In conclusion, this paper provides CROs with a methodological approach for efficiently building relationships with insurance agencies by consistently addressing TCoR-based dealings.


Mathematics ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 295
Author(s):  
Matteo Brachetta ◽  
Claudia Ceci

We investigate an optimal reinsurance problem for an insurance company taking into account subscription costs: that is, a constant fixed cost is paid when the reinsurance contract is signed. Differently from the classical reinsurance problem, where the insurer has to choose an optimal retention level according to some given criterion, in this paper, the insurer needs to optimally choose both the starting time of the reinsurance contract and the retention level to apply. The criterion is the maximization of the insurer’s expected utility of terminal wealth. This leads to a mixed optimal control/optimal stopping time problem, which is solved by a two-step procedure: first considering the pure-reinsurance stochastic control problem and next discussing a time-inhomogeneous optimal stopping problem with discontinuous reward. Using the classical Cramér–Lundberg approximation risk model, we prove that the optimal strategy is deterministic and depends on the model parameters. In particular, we show that there exists a maximum fixed cost that the insurer is willing to pay for the contract activation. Finally, we provide some economical interpretations and numerical simulations.


2020 ◽  
Vol 33 (11) ◽  
pp. 5131-5172 ◽  
Author(s):  
Sean J Flynn ◽  
Andra C Ghent ◽  
Alexei Tchistyi

Abstract We analyze how Dodd-Frank-mandated risk retention affects the information investors extract from issuers’ retention choices in the CMBS market. We show that the required retention level is both binding and stringent. Although this implies issuers cannot signal using the level of retention, we provide a model showing that signaling can occur by varying the retention structure. The model is consistent with spreads being empirically lower in deals with a purely first-loss retention structure. A stated concern of rulemakers is asymmetric information. However, we show that, post-crisis, the level of asymmetric information in this market is quite low.


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