Saving the Seas: The Economic Justification for Marine Reserves

We contribute to the understanding of marine reserves and the management of renewable resources with uncertainty. We show that the key benefit of reserves is that they increase resilience, or the speed it takes a population to return to a former state following a negative shock. Resilience can also increase resource rents even with optimal harvesting. We contradict the accepted wisdom that reserves have no value if harvesting is optimal, reserves and optimal output controls are equivalent, reserves have value only with overexploited populations and that reserves must be large to offer benefits to fishers.Marine Reserves, Uncertainty

Hydrogen-oxygen proton-exchange membrane fuel cells and electrolyzers

Hydrogen-oxygen solid polymer electrolyte (SPE) fuel cells and SPE electrolyzers (products of Hamilton Standard) both use a Proton-Exchange Membrane (PEM) as the sole electrolyte. These solid electrolyte devices have been under continuous development for over 30 years. This experience has resulted in a demonstrated ten-year SPE cell life capability under load conditions. Ultimate life of PEM fuel cells and electrolyzers is primarily related to the chemical stability of the membrane. For perfluorocarbon proton exchange membranes an accurate measure of the membrane stability is the fluoride loss rate. Millions of cell hours have contributed to establishing a relationship between fluoride loss rates and average expected ultimate cell life. This relationship is shown. Several features have been introduced into SPE fuel cells and SPE electrolyzers such that applications requiring greater than or equal to 100,000 hours of life can be considered. Equally important as the ultimate life is the voltage stability of hydrogen-oxygen fuel cells and electrolyzers. Here again the features of SPE fuel cells and SPE electrolyzers have shown a cell voltage stability in the order of 1 microvolt per hour. That level of stability has been demonstrated for tens of thousands of hours in SPE fuel cells at up to 500 amps per square foot (ASF) current density

Hydrogen-oxygen proton-exchange membrane fuel cells and electrolyzers

Hydrogen-oxygen SPE fuel cells and SPE electrolyzers (products of Hamilton Standard) both use a Proton-Exchange Membrane (PEM) as the sole electrolyte. The SPE cells have demonstrated a ten year life capability under load conditions. Ultimate life of PEM fuel cells and electrolyzers is primarily related to the chemical stability of the membrane. For perfluorocarbon proton-exchange membranes an accurate measure of the membrane stability is the fluoride loss rate. Millions of cell hours have contributed to establishing a relationship between fluroride loss rates and average expected ultimate cell life. Several features were introduced into SPE fuel cells and SPE electrolyzers such that applications requiring greater than or equal to 100,000 hours of life can be considered. Equally important as the ultimate life is the voltage stability of hydrogen-oxygen fuel cells and electrolyzers. Here again the features of SPE fuel cells and SPE electrolyzers have shown a cell voltage stability in the order of 1 microvolt per hour. That level of stability were demonstrated for tens of thousands of hours in SPE fuel cells at up to 500 amps per square foot (ASF) current density. The SPE electrolyzers have demonstrated the same at 1000 ASF. Many future extraterrestrial applications for fuel cells require that they be self recharged. To translate the proven SPE cell life and stability into a highly reliable extraterrestrial electrical energy storage system, a simplification of supporting equipment is required. Static phase separation, static fluid transport and static thermal control will be most useful in producting required system reliability. Although some 200,000 SPE fuel cell hours were recorded in earth orbit with static fluid phase separation, no SPE electrolyzer has, as yet, operated in space

General Hospitals, Specialty Hospitals and Financially Vulnerable Patients

Examines whether specialty hospitals draw well-insured patients away from general and safety-net hospitals, reducing their ability to cross-subsidize less profitable services and uncompensated care, in three cities. Notes challenges and implications

A Meta-narrative Review of Textured Implants and Associated Lymphoma Risks

In 2011, the Food and Drug Administration (FDA) identified that breast implants are associated with breast implant-associated anaplastic large cell lymphoma (BIA-ALCL). Until 2022, a total of 1130 cases were globally recorded (Health, 2021). Even though researchers are attempting to determine the risks, the accurate etiology has not been determined yet. Comparisons of previous published works are widespread in different potential causes. Hence, we aim to focus on defining how different implants link to BIA-ALCL, especially smooth and textured implants. The review follows the meta-narrative approach with the Pubmed database (2018- now) to collect, combine, and contrast data. All the articles focus on the correlation between the texture of breast implants and BIA-ALCL. The 5 selected studies highlighted similarities and differences to find gaps, limitations among articles and investigate answers for new findings. Classification systems for implant surfaces are divided into groups based on texturing, the parameters of surface area, and bacteria growth. There have been no confirmed cases of BIA-ALCL in patients who have received only smooth breast implants while evidence has reflected textured surface links to the risk of this cancer. Intermediate and high textured surfaces are 10 times higher that links to ALCL than low-surface-area texture (Siltex). Silimed polyurethane, measured as surface grade 4, carries the highest surface area and surface roughness and has been demonstrated to have significantly higher rates of bacterial growth. Without a uniform definition, using the same terms (eg, microtexture and macrotexture) in multiple contexts causes difficulties to compare risks for BIA-ALCLhttps://openworks.mdanderson.org/rmps/1001/thumbnail.jp

Safer selection and use of pesticides: Integrating risk assessment, monitoring and management of pesticides

Crop Production/Industries,