From data rich to data-limited harvest strategies—does more data mean better management?

2016 ◽  
Vol 74 (3) ◽  
pp. 670-686 ◽  
Author(s):  
Catherine M. Dichmont ◽  
Elizabeth A. Fulton ◽  
Rebecca Gorton ◽  
Miriana Sporcic ◽  
L. Richard Little ◽  
...  

Harvest strategies (HSs) have been applied to many data-rich fisheries, and are now increasingly being applied in data-limited situations. These have been evaluated using simulation frameworks, including management strategy evaluation (MSE), but few studies have considered the full spectrum from data-rich to data-limited strategies, in the context of the risk-cost-catch trade-off. This involves evaluating whether the cost of implementing a HS, the risk to the resource and catch taken from the resource have been appropriately balanced, given the value of the resource. HSs implemented for Australian Commonwealth fisheries were placed in eight tiers, ranging from data-rich to data-limited, and their performance evaluated using an MSE based on a full end-to-end ecosystem model. Generally, the risk to the resource increased as fewer data were available, due to biases in the assessments and slow response times to unexpected declines in resource status. The most data-rich tiers maximize discounted catches and profits over a 45-year projection period. However, the opportunity costs response is variable, and shows that the benefit of short-term high catches have to be compensated by resource recovery in the long term. On average, more data leads to improved management in terms of risk of being overfished and not reaching a target, but this requires lower initial catches to recover the resources and lower short-term discounted profits.

Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 830
Author(s):  
Temple Grandin

In the U.S., the most severe animal welfare problems caused by COViD-19 were in the pork industry. Thousands of pigs had to be destroyed on the farm due to reduced slaughter capacity caused by ill workers. In the future, both short-term and long-term remedies will be needed. In the short-term, a portable electrocution unit that uses scientifically validated electrical parameters for inducing instantaneous unconsciousness, would be preferable to some of the poor killing methods. A second alternative would be converting the slaughter houses to carcass production. This would require fewer people to process the same number of pigs. The pandemic revealed the fragility of large centralized supply chains. A more distributed supply chain with smaller abattoirs would be more robust and less prone to disruption, but the cost of pork would be greater. Small abattoirs can coexist with large slaughter facilities if they process pigs for specialized premium markets such as high welfare pork. The pandemic also had a detrimental effect on animal welfare inspection and third party auditing programs run by large meat buyers. Most in-person audits in the slaughter plants were cancelled and audits were done by video. Video audits should never completely replace in-person audits.


2019 ◽  
Author(s):  
soumya banerjee

Modelling and forecasting port throughput enables stakeholders to make efficient decisions ranging from management of port development, to infrastructure investments, operational restructuring and tariffs policy. Accurate forecasting of port throughput is also critical for long-term resource allocation and short-term strategic planning. In turn, efficient decision-making enhances the competitiveness of a port. However, in the era of big data we are faced with the enviable dilemma of having too much information. We pose the question: is more information always better for forecasting? We suggest that more information comes at the cost of more parameters of the forecasting model that need to be estimated. We comparemultiple forecasting models of varying degrees of complexity and quantify the effect of the amount of data on model forecasting accuracy. Our methodology serves as a guideline for practitioners in this field. We also enjoin caution that even in the era of big data more information may not always be better. It would be advisable for analysts to weigh the costs of adding more data: the ultimate decision would depend on the problem, amount of data and the kind of models being used.


2021 ◽  
pp. medethics-2021-107235
Author(s):  
Nancy S Jecker

This paper considers the proposal to pay people to get vaccinated against the SARS-CoV-2 virus. The first section introduces arguments against the proposal, including less intrusive alternatives, unequal effects on populations and economic conditions that render payment more difficult to refuse. The second section considers arguments favouring payment, including arguments appealing to health equity, consistency, being worth the cost, respect for autonomy, good citizenship, the ends justifying the means and the threat of mutant strains. The third section spotlights long-term and short-term best practices that can build trust and reduce ‘vaccine hesitancy’ better than payment. The paper concludes that people who, for a variety of reasons, are reluctant to vaccinate should be treated like adults, not children. Despite the urgency of getting shots into arms, we should set our sights on the long-term goals of strong relationships and healthy communities.


2019 ◽  
Vol 18 (3) ◽  
pp. 97-119 ◽  
Author(s):  
Jesper Haga ◽  
Fredrik Huhtamäki ◽  
Dennis Sundvik

ABSTRACT In this study, we investigate how country-level long-term orientation affects managers' willingness to engage in earnings management and choice of earnings management strategy. Using a comprehensive dataset of 47 countries for the period from 2003 to 2015, we find that firms in long-term-oriented cultures rely relatively more on earnings management through accruals, while firms in short-term-oriented cultures engage in relatively more real earnings management. Furthermore, we find a larger discontinuity around earnings benchmarks in long-term-oriented cultures suggesting that manipulation of accruals enables benchmark beating with high precision. JEL Classifications: M14; M16; M21; M41.


2016 ◽  
Vol 13 (24) ◽  
pp. 6651-6667 ◽  
Author(s):  
Jing Tang ◽  
Guy Schurgers ◽  
Hanna Valolahti ◽  
Patrick Faubert ◽  
Päivi Tiiva ◽  
...  

Abstract. The Arctic is warming at twice the global average speed, and the warming-induced increases in biogenic volatile organic compounds (BVOCs) emissions from Arctic plants are expected to be drastic. The current global models' estimations of minimal BVOC emissions from the Arctic are based on very few observations and have been challenged increasingly by field data. This study applied a dynamic ecosystem model, LPJ-GUESS, as a platform to investigate short-term and long-term BVOC emission responses to Arctic climate warming. Field observations in a subarctic tundra heath with long-term (13-year) warming treatments were extensively used for parameterizing and evaluating BVOC-related processes (photosynthesis, emission responses to temperature and vegetation composition). We propose an adjusted temperature (T) response curve for Arctic plants with much stronger T sensitivity than the commonly used algorithms for large-scale modelling. The simulated emission responses to 2 °C warming between the adjusted and original T response curves were evaluated against the observed warming responses (WRs) at short-term scales. Moreover, the model responses to warming by 4 and 8 °C were also investigated as a sensitivity test. The model showed reasonable agreement to the observed vegetation CO2 fluxes in the main growing season as well as day-to-day variability of isoprene and monoterpene emissions. The observed relatively high WRs were better captured by the adjusted T response curve than by the common one. During 1999–2012, the modelled annual mean isoprene and monoterpene emissions were 20 and 8 mg C m−2 yr−1, with an increase by 55 and 57 % for 2 °C summertime warming, respectively. Warming by 4 and 8 °C for the same period further elevated isoprene emission for all years, but the impacts on monoterpene emissions levelled off during the last few years. At hour-day scale, the WRs seem to be strongly impacted by canopy air T, while at the day–year scale, the WRs are a combined effect of plant functional type (PFT) dynamics and instantaneous BVOC responses to warming. The identified challenges in estimating Arctic BVOC emissions are (1) correct leaf T estimation, (2) PFT parameterization accounting for plant emission features as well as physiological responses to warming, and (3) representation of long-term vegetation changes in the past and the future.


2019 ◽  
Vol 76 (4) ◽  
pp. 813-823 ◽  
Author(s):  
Robert B Thorpe ◽  
José A A De Oliveira

Abstract Maximum sustainable yield (MSY) is a well-established concept that is mandated by legislation, and has a clear theoretical meaning in terms of a single stock. However, its definition is problematic in a multispecies setting, which makes it more difficult to apply the MSY principle. In this study of the North Sea fish community, we consider several possible MSY candidates, and evaluate them in terms of their ability to produce optimum long-term yield whilst avoiding unacceptable risk of stock impairment. We perform this evaluation with an ensemble of size-structured models using a management strategy evaluation approach, in which harvest control rules (HCRs) are used to determine levels of fishing as a function of the proposed MSY target and stock status, taking account of recruitment and model parameter uncertainties. We find that HCRs of the type considered here are always useful in the scenarios we tested, as they reduce overfishing risk much more than average long-term yield. This is independent of the precise form of the HCR, so it is more important to implement one rigorously than obsess over the rule details. For a lax definition of overfishing, which accepts relatively severe stock depletion (B < 10% B0), and using HCRs, risks are “low” across all strategies, and the Nash equilibrium is the best performing MSY approach considered here. For more stringent definitions of “at risk” (e.g. likelihood of B < 20% of B0), the application of HCRs can allow a range of alternative formulations of MSY. Thus, the definition of MSY may be sensitive to judgements about acceptable levels of risk, and consistent application of a sensible management framework may be more important than developing the best possible theoretical definition of MSY.


Significance On July 15, the House of Representatives passed a short-term funding measure, against the wishes of many in the Senate. US infrastructure is facing a fiscal crunch. Taxes on gasoline have traditionally supported highway appropriations. However, eroding purchasing power and greater fuel efficiency means that about 30% of highway funding must be found from other sources, difficult in the current Congress. The present round of appropriations expires on July 31. Impacts A corporate tax might provide a long-term resolution, but the pursuit of it would come at the cost of seeking more modest solutions. These would provide stability for a year or two, necessary for projects of long duration. If corporate tax reform is not completed before the end of 2015, it will probably not get done in a presidential election year. If Congress were to rely on the prospect of these taxes for the HTF, it might find itself in a similar position in a few months.


2014 ◽  
Vol 2 (1) ◽  
pp. 40 ◽  
Author(s):  
Chirantan Banerjee ◽  
Lucie Adenaeuer

With rising population and purchasing power, demand for food and changing consumer preferences are building pressure on our resources. Vertical Farming, which means growing food in skyscrapers, might help to solve many of these problems. The purpose of this study was to construct a Vertical Farm and thereof investigate the economic feasibility of it. In a concurrent Engineering Study initiated by DLR Bremen, a farm, 37 floors high, was designed and simulated in Berlin to estimate the cost of production and market potential of this technology. It yields about 3,500 tons of fruits and vegetables and ca. 140 tons of tilapia fillets, 516 times more than expected from a footprint area of 0.25 ha due to stacking and multiple harvests. The investment costs add up to € 200 million, and it requires 80 million litres of water and 3.5 GWh of power per year. The produced food costs between € 3.50 and € 4.00 per kilogram. In view of its feasibility, we estimate a market for about 50 farms in the short term and almost 3000 farms in the long term. To tap the economic, environmental and social benefits of this technology, extensive research is required to optimise the production process.


2021 ◽  
pp. 2150008
Author(s):  
MARIIA BELAIA ◽  
JUAN B. MORENO-CRUZ ◽  
DAVID W. KEITH

We introduce solar geoengineering (SG) and carbon dioxide removal (CDR) into an integrated assessment model to analyze the trade-offs between mitigation, SG, and CDR. We propose a novel empirical parameterization of SG that disentangles its efficacy, calibrated with climate model results, from its direct impacts. We use a simple parameterization of CDR that decouples it from the scale of baseline emissions. We find that (a) SG optimally delays mitigation and lowers the use of CDR, which is distinct from moral hazard; (b) SG is deployed prior to CDR while CDR drives the phasing out of SG in the far future; (c) SG deployment in the short term is relatively independent of discounting and of the long-term trade-off between SG and CDR over time; (d) small amounts of SG sharply reduce the cost of meeting a [Formula: see text]C target and the costs of climate change, even with a conservative calibration for the efficacy of SG.


2017 ◽  
Vol 5 (2) ◽  
pp. 91
Author(s):  
Rendys Septalia ◽  
Nunik Puspitasari

Contraception was the most effective way to control the population growth. The most widely favored in Indonesia was a short-term contraceptive methods. High attainment acceptor on short-term contraceptive methods because short-term contraceptive methods was a methods contraception affordable, while the fees for the long-term contraceptive methods was more expensive. The incidence of injectable contraceptives and pills drop-out was higher than the long-term contraceptive methods that contributed to the failure of population growth control program. This study to analyze the factors that affect the selection contraceptive methods. This study was an observational study with cross sectional design. Sampling with systematic random and obtained were 79 acceptors. The independent variables were the cost of contraceptive use, non-material costs (experience side effects), cultural obstacle, social adjustments obstacle, physic and mental health obstacle, and accessibility obstacle. Data collected using the questionnaire and analyse by multiple logistic regression. The results showed that the significant factor were the cost of contraceptive usage (pvalue = 0.002), the cost of non-material (experience side eff ects) (pvalue = 0.007), and factors that didn’t have signifi cant influence were cultural obstacle (pvalue = 0.105), social adjustments obstacle (pvalue = 0.999), physic and mental health obstacle (pvalue = 0.920), and accessibility obstacle (pvalue = 0.438). The conclusion were the cost of contraceptive use and non-material costs (experience side eff ects) aff ected the selection of contraception. It was need the cooperation between religious leaders, community leaders, and health care workers in a common understanding on the cost of contraceptive usage.


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