Economic spillover from Natural Protected Areas to conventional tourist destinations

This paper examines the role of Natural Protected Areas (NPAs) as a source of economic spillovers for mass tourism destinations in Mexico. An econometric model was used to explain the number of booked rooms in tourism destinations as a function of proximity to NPAs, controlling for destination characteristics. A conservative estimate suggests that some rooms booked by foreign visitors can be explained by proximity to NPAs. Our results open public policy options, such as a compensating mechanism from conventional tourism to fund NPAs and show that they would be economically efficient and contribute to sustainability.

SOCIAL SECURITY AND LONGEVITY RISK: THE CASE OF RISKY BEQUEST INCOME

This paper quantifies the welfare gains from Social Security when individuals face uninsurable longevity risk. While past researchers have studied this basic question, we do so from a unique perspective. In contrast to traditional macroeconomic models that abstract from specific linkages between parents and children, in our model, children are born to specific parents whose longevity is uncertain. And because parental asset holdings evolve over the life of the parent, children face uninsurable bequest income risk in addition to their own longevity risk. We find that Social Security improves ex ante expected utility by 3.4% of lifetime consumption (for the second generation). Because our baseline analysis assumes full information and optimal hedging of longevity risk, we treat these welfare gains as a conservative estimate, and we show that the gains are significantly larger when individuals fail to hedge their longevity risk.

A Practical Perspective for a Conservative Estimate of Blood Glucose Level during Restaurant Dining and Supermarket Shopping

Foods today are so diverse and enjoyable, making healthy choices difficult. In this perspective, an in vitro-in silico approach for obtaining a conservative estimate of the postprandial blood glucose concentration, which is a realistic estimate nevertheless, after intake of a certain portion of meals is proposed. The rationales and feasibilities of the approach are described and discussed to an extent. The key idea is to first measure the maximum amount of glucose released in an in vitro test under standardized conditions from a specified serving size of a meal or dish or a packaged product sold in a supermarket. The value can then be translated by a literate consumer to the highest estimate of blood glucose rise prior to purchasing or eating through an established in silico blood glucose prediction model in the medical field. The strategy proposed here would help health conscious (diabetics included) and other life quality conscious individuals to make quantitative decisions on consuming the portions of different foods of desire. This strategy may be more effective in reality compared to the conventional GI (Glycemic Index) and GL (Glycemic Load) concepts.

Analytical study on stability of microspheres in syntactic foams structure under hydrostatic compression

This paper analyses prediction methods for failure pressure of microspheres in the structure of syntactic foams, discussing several micromechanical models. The solutions were obtained as per linear elasticity theory and finite-element method. It was investigated how geometric and physical & mechanical characteristic of syntactic foams depend on its components. Pressure failure is much lower if the boundary of the medium is close to the inclusions. This paper suggests an analytical model that yielded conservative estimate of critical pressure for microspheres.

Explaining Governors’ Response to the COVID-19 Pandemic in the United States

What has been the response of U.S. governors to the COVID-19 pandemic? In this research note, we explore the determinants of implementing stay-at-home orders, focusing on governors’ characteristics in the early stage of the pandemic. In our most conservative estimate, being a Democratic governor increased the probability of implementing a stay-at-home order by more than 50%. Moreover, we found that the probability of implementing a statewide stay-at-home order was about 40% more likely for governors without term limits than governors with term limits. We also found that Democratic governors and governors without term limits were significantly faster to adopt statewide orders than Republican governors and governors with term limits. There is evidence of politics as usual in these unusual times.

SOLVING THE PUZZLE OF THE BIVALVE SHELL FRAGMENT: INFERRING THE ORIGINAL ABUNDANCE AND SIZE FREQUENCY FROM THE FRAGMENTED RECORD

ABSTRACT Much of the contribution of bivalves to paleoecology is based on the fraction preserved whole. The use of fragments has been limited by the inability to reconstruct the whole shell. For this study, shells of selected species were broken, metrics obtained for shell reconstruction, and a stepwise model developed and tested to evaluate the potential of reconstructing whole shells from fragments. The model is based on the facts that shell thickness is well correlated with shell length, width, and weight, that fragments can be assigned to shell areas, and that each shell area can be matched to a potential donor shell by combinations of length, width, and weight. Simulations using the model show that shell reconstructions are feasible and that the size frequency can be reconstructed more accurately than the number of shells. If all fragments are preserved, shell number tends to be modestly overestimated. Assuming fragment loss, the shell number estimated will be a conservative estimate of original abundance. Reconstructed size frequencies did not differ significantly from the original size frequencies of the whole shells even if 40% of the fragments were not preserved. Biovolume, consequently, may also be estimable. Standardly, bivalve fragments are enumerated by counting intact umbos. If all fragments are preserved, this approach is preferable, as shell model reconstructions overestimate abundance under that circumstance. However, the expectation that fragments with intact umbos are uniquely well preserved is unrealistic and if fragment loss has occurred, relying on all fragments may provide an improved estimate of the original abundance and, in addition, an estimate of the size frequency and the latter proves to be robust even with 40% of the fragments lost.

Pull Test Study of the MFL-A Performance Within Casings to Improve ILI-Based Corrosion Management of Cased Pipes

High resolution magnetic flux leakage (MFL) in-line inspection (ILI) technology has proven to be one of the most effective approaches to manage corrosion anomalies within the pipeline industry. However, due to the presence of extra metal, pipeline casings are suspected of impacting the detection and sizing accuracy of MFL systems for metal loss features when they are located under casings. A research project was carried out by TC Energy (TCE) with ROSEN to better understand the effect of pipeline casings on the performance of axially-aligned MFL ILI (MFL-A) technology. The study involved full-scale pull through testing to investigate the effects of various casing conditions and the presence of different types of casing spacers on the inspection system’s sizing and detection performance for corrosion anomalies, including the casing eccentricity, the presence of metallic and electrolytic shorting, and the presence of different types of casing spacers. The testing for various eccentricity and shorting scenarios were compared to an uncased baseline scenario. An important lesson learned by the project team through this research is the importance of identifying key factors that influence the system performance when analyzing the testing results. Failure in doing so can lead to less meaningful results: in this case, an overly conservative estimate of the sizing performance that does not discriminate appropriately where the system performed well and where the system performed worse than expected. The impact of such a broad-brushing and overly conservative estimate in the MFL system performance to pipeline integrity decisions is very significant and can result in a large number of unnecessary repairs in practice. With comprehensive data analytics, it was identified that the key factors affecting the tool performance for cased pipes are the small annulus gaps between the casing and the carrier pipe at the feature location, and the presence of certain types of spacers. For the vast majority of cases, the ILI performance under casings is comparable to the performance for uncased pipes. The results from this research suggests that with appropriate consideration of the system performance, TCE’s probabilistic ILI based corrosion management program can effectively manage corrosion anomalies within cased pipes using ILI. Additional research and testing are underway to further support this conclusion.

Entry screening and multi-layer mitigation of COVID-19 cases for a safe university reopening

We have performed detailed modeling of the COVID-19 epidemic within the State of Illinois at the population level, and within the University of Illinois at Urbana-Champaign at a more detailed level of description that follows individual students as they go about their educational and social activities. We ask the following questions: (1) How many COVID-19 cases are expected to be detected by entry screening? (2) Will this initial bump in cases be containable using the mitigation steps being undertaken at UIUC? Our answers are: (1) Assuming that there are approximately 45,000 students returning to campus in the week beginning August 15, 2020, our most conservative estimate predicts that a median of 270 ± 90 (minimum-maximum range) COVID-19 positive cases will be detected by entry screening. The earliest estimate for entry screening that we report was made on July 24th and predicted 198 ± 90 (68% CI) positive cases. (2) If the number of returning students is less, then our estimate just needs to be scaled proportionately. (3) This initial bump will be contained by entry screening initiated isolation and contact tracing, and once the semester is underway, by universal masking, a hybrid teaching model, twice-weekly testing, isolation, contact tracing, quarantining and the use of the Safer Illinois exposure notification app.

Estimate of COVID-19 case prevalence in India based on surveillance data of patients with severe acute respiratory illness

In absence of extensive testing for SARS-CoV-2, true prevalence of COVID-19 cases in India remain unknown. In this study, a conservative estimate of prevalence of COVID-19 is calculated based on the age wise COVID-19 positivity rate among patients with severe respiratory illness as reported by Indian Council of Medical Research. Calculations in the study estimates a cumulative number of 17151 COVID-19 positive cases by the end of April 2, 2020.

Critical fluid volumes and the start of 'self-sustaining' fracture ascent

<p>In theory, pockets of fluid in brittle media can be transported large distances, provided that both the fluid volume is large enough, such that fluid pressures can fracture the rock, and that stress gradients exist causing asymmetric growth of the fracture's front. Currently, industrial injections are deemed safe based on empirical observations of volumes, rates and pressures from closed-access industrial data. Existing theoretical models are difficult to use a priori to predict the critical volume of fluid that will cause unhindered fracture ascent, as they are expressed in terms of the fracture’s length, which is hard to predict a priori and difficult to measure. Here we constrain scale-independent critical volumes as a function of only rock and fluid properties by supplementing simple analytical models with numerical simulations in three dimensions. We apply our model to laboratory and natural settings, showing that the volumes we estimate match well with laboratory data and can be used as a conservative estimate in geological applications.</p>