scholarly journals Paradoxes of Poweshiek Skipperling (Oarisma poweshiek) (Lepidoptera: Hesperiidae): Abundance Patterns and Management of a Highly Imperiled Prairie Species

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Ann B. Swengel ◽  
Scott R. Swengel
Keyword(s):  
Tallgrass Prairie ◽  
Fire Management ◽  
First Year ◽  
Case Scenario ◽  
Worst Case ◽  
Abundance Patterns ◽  
In Fire ◽  
Percent Unit ◽  
Oarisma Poweshiek

Although Oarisma poweshiek sometimes occurred in localized abundance, its known range is centered on the highly decimated northern tallgrass prairie of North America. To aid its conservation, we analyze surveys from 1988 to 1997 of populations no longer being found. While we recorded 2403 individuals at 20 sites, five sites had 87% of individuals, while 12 sites had only 2% of individuals. Most surveys during O. poweshiek flight had zero individuals recorded. In peak vegetative characteristics for O. poweshiek, fire management had the highest mean abundance but the lowest median abundance and lowest percent occurrence compared to idling and haying. Mean abundance was by far the lowest in the first year postfire compared to longer since fire. Median abundance and percent unit surveys where O. poweshiek was found indicated higher abundances the longer since fire. Although this skipper occasionally exhibited super-recoveries after fire, the median result in fire-managed occupied sites was zero. In a few years, abundance appeared synchronized across many sites, either low (1993, 1997) or high (1994-1995). It is only through a constant focus on avoiding the worst-case scenario that the rare best-case scenario of long-term population persistence appears possible for O. poweshiek.

A Case Study - Life Extension of Offshore Bridge Bearings

2021 ◽  
Author(s):  
Ahmed Abdelkhalek ◽  
Govindavilas Sudhesh ◽  
Anjan Sarkar ◽  
Mohammed Eissa
Keyword(s):  
Cost Savings ◽  
Holistic Approach ◽  
Life Extension ◽  
Case Scenario ◽  
Worst Case ◽  
Maintenance And Repair ◽  
Seasonal Monitoring ◽  
The Impact ◽  
Bridge Bearings

Abstract Structural bearings of 47 offshore platform-link bridges with average age of 40 years were inspected and recommended for replacements due to their poor condition. Replacement of bridge bearings involves major risk and production interruptions given the structural modifications, and critical piping and E&I disconnections required for safe jacking-lifting activities required during the process. This paper presents the approach adopted to assure the integrity of the bridges and extend their lives without the need to replace the bearings. The approach employed failure mode and effect analysis to identifying and narrowing down areas that need focused efforts while tackling the problem. Scenario based structural assessments were carried out to examine the impact of the level of movement-allowing bearings functionality on the integrity of the bridge and its supporting structures; identify critical locations to be targeted during focused inspections; and establish envelopes for monitoring thermal expansion and contraction of the bridges. Guidelines were developed and implemented for integrated inspection-maintenance and repair campaign, which aimed to tackle corrosion issues and to install movement-monitoring indicators. Indicator seasonal monitoring is employed to establish the functionality of bearings on the long-term. The what-if structural assessments revealed that even in the worst-case scenario (in which the bearing are completely jammed) the option of local strengthening of the bridge and its supporting elements is more attractive than bearing replacement. The integrated inspection-maintenance and repair campaigns revealed that excessive corrosion levels observed from historic visual inspections on external non-critical bearing components (e.g: guide plates, angles, etc.) is not indicative of the condition of the internal load-bearing components (pedestals) which experienced much lower corrosion levels. The seasonal monitoring of bridge movements revealed that the 40+ years old Teflon pads are still functional and allow the bridges expansion and contraction. The developed holistic approach enabled demonstration of the fitness for service of the bearings, and provided means for assuring their long-term performance through monitoring. The results assured safety, integrity and delivered significant cost savings through aversion brownfield modifications, and production loss associated with bridge jacking and bearing replacement operations.

scholarly journals Bisphenol A Release from Dental Composites and Resin-Modified Glass Ionomers under Two Polymerization Conditions

Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 46
Author(s):  
Antonin Tichy ◽  
Marketa Simkova ◽  
Radka Vrbova ◽  
Adela Roubickova ◽  
Michaela Duskova ◽  
...  
Keyword(s):  
Bisphenol A ◽  
Artificial Saliva ◽  
Daily Intake ◽  
Dental Resin ◽  
Case Scenario ◽  
Worst Case ◽  
Initial Release ◽  
Liquid Chromatography Tandem Mass ◽  
Polymerization Conditions

Bisphenol A (BPA)-based monomers are commonly contained in dental resin-based materials. As BPA is an endocrine disruptor, its long-term release from restorative composites and resin-modified glass ionomers (RM-GICs) under two polymerization conditions was measured in this study. Specimens of two conventional composites containing BPA-based monomers, two “BPA-free” composites, and two RM-GICs were polymerized from one side for 20 s at 1300 mW/cm2 or for 5 s at 3000 mW/cm2. The amounts of BPA released in artificial saliva and methanol after 1, 4, 9, 16, 35, 65, 130, and 260 days were measured using liquid chromatography–tandem mass spectrometry. The highest amounts of BPA were released from conventional composites, followed by RM-GICs, while the least was released from “BPA-free” composites. Amounts of released BPA were significantly higher in methanol and decreased gradually after the first day. Fast polymerization (5 s at 3000 mW/cm2) resulted in a significantly higher release of BPA after 1 day, but the effect of polymerization conditions was not significant overall. In conclusion, fast polymerization increased the initial release of BPA, but the released amounts were significantly lower than the current tolerable daily intake (4 μg/kg body weight/day) even in methanol, representing the worst-case scenario of BPA release.

scholarly journals Vivax malaria in children: clinical features and response to chloroquine.

1969 ◽  
Vol 39 (4) ◽  
pp. 364-377
Author(s):  
Jaime Carmona Fonseca ◽  
Rosa M. Uscátegui ◽  
Adriana María Correa
Keyword(s):  
Vivax Malaria ◽  
Standard Dose ◽  
Therapeutic Option ◽  
Normal Liver ◽  
Acute Attack ◽  
Case Scenario ◽  
Worst Case ◽  
Intention To Treat ◽  
Late Failure

Introduction: In Colombia is not very common to find updated information about vivax malaria in children. Aims: Describe the clinical and paraclinical disease picture and evaluate the standard dose of chloroquine effectiveness as a cure for the acute attack of vivax malaria in children between 4 and 10 years old. Methods: Experimental design, balanced, not blind, 82 patients and habitants in El Bagre and Turbo, Colombia. Follow-up: 30 days. Results: Symptoms-signs agreed with the known. There were found 62% long-term malnutrition, 53% anemia, low retinol (19 μg/dl), normal leukocyte count, normal liver tests and normal creatinine coefficient. After 25-28 day of treatment, all alterations had disappeared on children except malnutrition. According with the analysis techniques, the chloroquine late failure proportion was: by the intention to treat 2.4% (0 to 24%), by the protocol 2.6% (0 to 25%), and in the worst-case scenario 7.3% (0 to 29%). Conclusion: The clinical and paraclinical depict was similar than adults. Malaria, was the main responsible for clinics and paraclinical alterations. Chloroquine, without primaquine, proved highly effective for the acute attack of vivax malaria in children and should be retained as the first therapeutic option.

scholarly journals Robust hedging in incomplete markets

2018 ◽  
Vol 18 (3) ◽  
pp. 473-493 ◽  
Author(s):  
SALLY SHEN ◽  
ANTOON PELSSER ◽  
PETER SCHOTMAN
Keyword(s):  
Incomplete Markets ◽  
Pension Fund ◽  
Model Misspecification ◽  
Risk Exposure ◽  
Investment Horizon ◽  
Case Scenario ◽  
Worst Case ◽  
Risky Assets ◽  
Substantial Risk

AbstractWe considered a pension fund that needs to hedge uncertain long-term liabilities. We modeled the pension fund as a robust investor facing an incomplete market and fearing model uncertainty for the evolution of its liabilities. The robust agent is assumed to minimize the shortfall between the assets and liabilities under an endogenous worst-case scenario by means of solving a min–max robust optimization problem. When the funding ratio is low, robustness reduces the demand for risky assets. However, cherishing the hope of covering the liabilities, a substantial risk exposure is still optimal. A longer investment horizon or a higher funding ratio weakens the investor's fear of model misspecification. If the expected equity return is overestimated, the initial capital requirement for hedging can be decreased by following the robust strategy.

scholarly journals Ambiguity, Nominal Bond Yields, and Real Bond Yields

2020 ◽  
Vol 2 (2) ◽  
pp. 177-192 ◽  
Author(s):  
Guihai Zhao
Keyword(s):  
Risk Premium ◽  
Bond Yields ◽  
Case Scenario ◽  
Worst Case ◽  
Inflation Risk ◽  
Expectations Hypothesis ◽  
Long Run ◽  
Short Run ◽  
The Difference

This paper presents an equilibrium bond-pricing model that jointly explains the upward-sloping nominal and real yield curves and the violation of the expectations hypothesis. Instead of relying on the inflation risk premium, the ambiguity-averse agent faces different amounts of Knightian uncertainty in the long run versus the short run; hence, the model-implied nominal and real short rate expectations are upward sloping under the agent’s worst-case equilibrium beliefs. The expectations hypothesis roughly holds under investors’ worst-case beliefs. The difference between the worst-case scenario and the true distribution makes realized excess returns on long-term bonds predictable. (JEL D81, D84, E23, E31, E43, E44, G12)

scholarly journals Equilibrium Pricing with Duality-Based Method: Approach for Market-Oriented Capacity Remuneration Mechanism

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 567
Author(s):  
Perica Ilak ◽  
Lin Herenčić ◽  
Ivan Rajšl ◽  
Sara Raos ◽  
Željko Tomšić
Keyword(s):  
Power System ◽  
Capacity Utilization ◽  
Case Scenario ◽  
Program Problem ◽  
Worst Case ◽  
Design Elements ◽  
Marginal Costs ◽  
Capacity Markets ◽  
Linear Program Problem

The crucial design elements of a good capacity remuneration mechanism are market orientation, insurance of long-term power system adequacy, and optimal cross-border generation capacity utilization. Having in mind these design elements, this research aims to propose a financially fair pricing mechanism that will guarantee enough new capacity and will not present state aid. The proposed capacity remuneration mechanism is an easy-to-implement linear program problem presented in its primal and dual form. The shadow prices in the primal problem and dual variables in the dual problem are used to calculate the prices of firm capacity which is capacity needed for long-term power system adequacy under capacity remuneration mechanism. In order to test if the mechanism ensures sufficient new capacity under fair prices, the mechanism is tested on the European Network of Transmission System Operators for Electricity (ENTSO-E) regional block consisting of Austria, Slovenia, Hungary, and Croatia with simulation conducted for a period of one year with a one-hour resolution and for different scenarios of the credible critical events from a standpoint of security of supply; different amounts of newly installed firm capacity; different short-run marginal costs of newly installed firm capacity; and different capacity factors of newly installed firm capacity. Test data such as electricity prices and electricity load are referred to the year 2018. The results show that the worst-case scenario for Croatia is an isolated system scenario with dry hydrology that results with high values of indicators expected energy not served (EENS), loss of load expectation (LOLE), and loss of load probability (LOLP) for Croatia. Therefore, new capacity of several hundred MW is needed to stabilize these indicators at lower values. Price for that capacity depends on the range of installed firm capacity and should be in range of 1000–7000 €/MW/year for value of lost load (VoLL) in Croatia of 1000 €/MWh and 3000–22,000 €/MW/year for VoLL of 3100 €/MWh that correlates with prices from already established capacity markets. The presented methodology can assist policymakers, regulators, and market operators when determining capacity remuneration mechanism rules and both capacity and price caps. On the other hand, it can help capacity market participants to prepare the most suitable and near-optimal bids on capacity markets.

Using the IPCC for Communicating Both the Full Extent of the Global Climate Emergency and the Required Response

2021 ◽  
Author(s):  
Peter Carter
Keyword(s):  
Climate Change ◽  
Market Failure ◽  
Global Climate ◽  
Case Scenario ◽  
Rcp Scenarios ◽  
Worst Case ◽  
Important Message ◽  
Value Judgements ◽  
Global Emissions

<p>Since the IPCC (2018) 1.5°C Report, the climate emergency is widely recognized. Then 2019 COP25 statement by IPCC Chair Dr H. Lee ,referring to the three recent IPCC Special Reports (2018,2019,2019) is crucial emphasizing that global emissions MUST decline by and from 2020. The Summaries for Policy Makers (SPMs) are convincing for communication as all world governments approve them. Though the IPCC assesses climate change, the environmental health emergency called climate change is climate system disruption from atmospheric greenhouse gas pollution. The IPCC assessments can be used to produce risk assessments. IPCC published climate change science reports are invaluable, especially the FAQs. The most important message in the IPCC (2014) AR5 and 1.5°C Report is that global emissions have to decline rapidly from 2020, via market failure corrections, for a 1.5°C and for a 2°C limit. The greatest impact to humanity is on food security, and from the IPCC we describe regional crop impacts and crop model limitations. We elucidate IPCC reports on confidence, carbon budget, net zero, negative emissions, value judgements, and recommendations. We clarify inertias, commitment, risks, and amplifying feedbacks. Long-term data trends, rather than only model projections, can now be relied on. We relate IPCC scenarios to worst-case, business-as-usual and best case. For risk we use the IPCC upper ranges, because long-term projected temperature increases are underestimated as they do not account for amplifying feedbacks or decline of carbon sinks, and are only based on a single median climate sensitivity (3C). Although the IPCC shows that atmospheric CO2 is "forever," IPCC SPM projections are all now only to 2100.  From the IPCC RCP scenarios the world is tracking closest to the worst case scenario (RCP8.5). On this scenario the IPCC 1.5°C Report projects 1.5°C by 2035 and 2°C  by 2047. The greatest risk to the future of humanity and most life is multiple inter-reinforcing amplifying feedbacks that lead to hothouse Earth and on to runaway. The evidence for multiple Arctic feedback emissions and Amazon die-back can be found in the IPCC 2014 5th assessment. This reinforces the imperative requiring immediate and rapid global emissions decline. </p>

scholarly journals Modelling of Health Risk Associated with the Intake of Pesticides from Romanian Fruits and Vegetables

2020 ◽  
Vol 12 (23) ◽  
pp. 10035
Author(s):  
Mariana Minuț ◽  
Mihaela Roșca ◽  
Raluca-Maria Hlihor ◽  
Petronela Cozma ◽  
Maria Gavrilescu
Keyword(s):  
Exposure Assessment ◽  
Pesticide Residues ◽  
Fruits And Vegetables ◽  
Daily Intake ◽  
Case Scenario ◽  
Worst Case ◽  
Short Term Exposure ◽  
Fruit Samples ◽  
German Children

This study is focused on the assessment of risks caused by pesticide residues to Romanian and other European populations, by modelling the acute and chronic risks considering short- and long-term exposures to pesticide residues in specific fruits and vegetables from different Romanian regions. Data were obtained from the Romanian 2016 official monitoring programme. For assessing the dietary risk, we used the Pesticide Residue Intake model—PRIMo. According to the official data, it was found that 50.44% of fruit samples and 28.25% of vegetable samples were contaminated with pesticides. Our study focused on acute risks and chronic risks (in a maximalist worst-case scenario) posed by pesticide residues in strawberries, apples, lettuce and potatoes, given both their high degree of consumption and contamination with pesticides. The short-term exposure assessment of children’s health due to consumption of apples, lettuce and potatoes contaminated with dimethoate, chlorothalonil and carbendazim, revealed exposure levels higher than the acute reference dose (ARfD, as 100%), raising acute risks. On the other hand, the long-term exposure assessment showed that the highest percentage from the acceptable daily intake (ADI, as 100%) was obtained for German children (DE child) (273.9%), followed by Netherlands children (NL child) (143.7%) diets, based on consumption of apples with dimethoate residues. Therefore, serious measures are needed for banning pesticides such as dimethoate, chlorothalonil and carbendazim from all countries in the EU. This would reduce the health risks generated by the consumption of contaminated fruits and vegetables.

scholarly journals Centennial response of Greenland’s three largest outlet glaciers

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Shfaqat A. Khan ◽  
Anders A. Bjørk ◽  
Jonathan L. Bamber ◽  
Mathieu Morlighem ◽  
Michael Bevis ◽  
...  
Keyword(s):  
Mass Loss ◽  
Sea Level Rise ◽  
Sea Level ◽  
Greenland Ice Sheet ◽  
External Forcing ◽  
Case Scenario ◽  
Worst Case ◽  
Worst Case Scenario ◽  
Historical Photographs

AbstractThe Greenland Ice Sheet is the largest land ice contributor to sea level rise. This will continue in the future but at an uncertain rate and observational estimates are limited to the last few decades. Understanding the long-term glacier response to external forcing is key to improving projections. Here we use historical photographs to calculate ice loss from 1880–2012 for Jakobshavn, Helheim, and Kangerlussuaq glacier. We estimate ice loss corresponding to a sea level rise of 8.1 ± 1.1 millimetres from these three glaciers. Projections of mass loss for these glaciers, using the worst-case scenario, Representative Concentration Pathways 8.5, suggest a sea level contribution of 9.1–14.9 mm by 2100. RCP8.5 implies an additional global temperature increase of 3.7 °C by 2100, approximately four times larger than that which has taken place since 1880. We infer that projections forced by RCP8.5 underestimate glacier mass loss which could exceed this worst-case scenario.

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