An Experimental Test of Buffer Utility as a Technique for Managing Pool-Breeding Amphibians

Vegetated buffers are used extensively to manage wetland-dependent wildlife. Despite widespread application, buffer utility has not been experimentally validated for most species. To address this gap, we conducted a six-year, landscape-scale experiment, testing how buffers of different widths affect the demographic structure of two amphibian species at 11 ephemeral pools in a working forest of the northeastern U.S. We randomly assigned each pool to one of three treatments (i.e., reference, 100m buffer, 30m buffer) and clearcut to create buffers. We captured all spotted salamanders and wood frogs breeding in each pool and examined the impacts of treatment and hydroperiod on breeding-population abundance, sex ratio, and recapture rate. The negative effects of clearcutting tended to increase as forest-buffer width decreased and be strongest for salamanders and when other stressors were present (e.g., at short-hydroperiod pools). Recapture rates were reduced in the 30m, but not 100m, treatment. Throughout the experiment for frogs, and during the first year post-cut for salamanders, the predicted mean proportion of recaptured adults in the 30m treatment was only 62% and 40%, respectively, of that in the reference treatment. Frog sex ratio and abundance did not differ across treatments, but salamander sex ratios were increasingly male-biased in both cut treatments. By the final year, there were on average, only about 40% and 65% as many females predicted in the 100m and 30m treatments, respectively, compared to the first year. Breeding salamanders at short-hydroperiod pools were about 10% as abundant in the 100m versus reference treatment. Our study demonstrates that buffers partially mitigate the impacts of habitat disturbance on wetland-dependent amphibians, but buffer width and hydroperiod critically mediate that process. We provide the first experimental evidence showing that 30-m-wide buffers may be insufficient for maintaining resilient breeding populations of pool-dependent amphibians, at least during the first six years post-disturbance

Conserving wetlands for humans and amphibians: a multidisciplinary approach to understanding the social and ecological effectiveness of New England\u27s wetland policies

Freshwater wetland ecosystems are a valuable resource, but current policies fail to prevent their continuing destruction. Policy-makers increasingly use decentralized wetland-buffer programs to address such policy failings, but scant research has evaluated whether these programs are both ecologically and socially effective. In the following dissertation, I address this gap using two complementary projects. For the first project, I assessed whether forested buffers are an effective tool for maintaining viable populations of pool-breeding amphibians. Such species spend their early life stages in vernal pools, which are small, highly productive wetlands, but use the surrounding forest during juvenile and adult life-stages. Though buffers are often prescribed for managing these species, buffer utility has never been experimentally tested. For this project, I used data from a landscape-scale experiment to determine whether wider buffers more efficiently mitigate the effects of forest disturbance on breeding-adult populations of spotted salamanders (Ambystoma maculatum) and wood frogs (Lithobates sylvaticus), two amphibian species that breed in vernal pools throughout eastern North America. This experiment was conducted at 11 natural vernal pools in an industrial forest in east-central Maine. Each pool was randomly assigned to one of three treatments (i.e., reference, 100m buffer, 30m buffer). Clearcutting was used to create experimental buffers. All spotted salamanders and wood frogs breeding in these pools over the six study years were captured, counted, sexed, and sized. I used generalized linear mixed effects regression to assess the relative impacts of buffer treatment and pool hydroperiod on breeding-adult population size, composition, and biomass. I found that clearcutting resulted in negative impacts to breeding-adult populations, but that buffer width was an important mitigating factor in the extent of these impacts. Specifically, narrower (30m) buffers were associated with altered salamander sex ratios, and for both species, diminished body size, condition, and biomass and fewer recaptures. In the wider (100m) buffer treatment, I detected negative effects on salamander sex ratios and abundance, and the biomass of both species. However, the 100m-treatment effects were largely limited to pools that were also stressed hydrologically. The observed negative effects potentially signal reduced local-population resiliency, which could scale up to regional-population and community-level effects, especially if other stressors were introduced to the system. Several, though not all, of the negative effects started to recover as the cuts regenerated, however, suggesting a temporally-finite window of reduced resiliency. Overall, these results provide the first experimental evidence showing that buffers that are only 30m wide may be insufficient for maintaining resilient local populations of pool-breeding amphibians. Whereas for my first project, I focused on the value of buffers for wildlife in a forestry setting, for my second project I examined decentralized wetland-buffer programs in exurban towns. In New England, many municipalities have local wetland-permit policies and land-use decision-making is largely devolved to municipal boards. While some evidence suggests that local wetland programs minimize development in and near wetlands, it does not explain why towns with similar programs sometimes have very different wetland-protection outcomes, if stakeholders support local wetland programs, or whether social outcomes feedback to influence ecological outcomes. I used case-study analysis to determine the specific factors driving, and the potential for interactions between, the ecological and social effectiveness (EE and SE) of municipal wetland-permitting programs in four southern New England towns. To assess EE, I used regression techniques to quantify spatial impacts to wetland ecosystems on 50 construction site plans per town. To determine SE, I conducted and qualitatively coded 45 key-informant interviews. I found that EE and SE both varied considerably across the four towns, despite broadly similar wetland-policies and demographic profiles. EE was largely a function of SE and policy details. In turn, SE was driven by multiple interacting factors, with no single prescription fitting all towns. Nevertheless, I did identify eight principal SE drivers that strongly shaped, facilitated, or were used to express SE. These included: having a conservation-based town identity, being able to communicate about wetland permitting, property-rights ethics, town organizational structure, education, wealth, public participation, and local politics. The case-studies show that local buffer programs can effectively protect wetlands if the necessary social factors are aligned. When social factors do not align, however, stakeholder malcontent can weaken EE and destabilize social relations. To help safeguard against such negative fallout, I provide a set of recommendations intended to enhance the SE and EE of local wetland programs. My research results, when combined and synthesized with previous research, ultimately indicate that buffers are critical for wetland-ecosystem integrity, but that wider buffers are needed than those currently used in developed landscapes. Equally important, however, the synthesized evidence suggests that buffers alone are an insufficient tool for protecting wetland ecosystems. Rather an effective wetland-management strategy must nurture the social dynamics associated with wetland-program implementation and integrate buffer policies with landscape-scale conservation planning

Effects of forest clear cutting on spotted salamander ( Ambystoma maculatum) migration

Upland buffer zones are a proposed management tool for vernal-pool-breeding amphibians. Substantial validation of buffers, via experimental upland habitat disturbance, is lacking. Specifically, no studies have examined immediate effects of clear cutting on spotted salamander (Ambystoma maculatum ) migration. I used clear cutting to experimentally manipulate upland buffer widths at 11 vernal pools. I then radiotracked 40 adult spotted salamanders at these pools, and modeled their migration with mixed-effects regression. Mean maximum distance from the pool was 106.0 +/- 15.4 m (range = 1.6 to 427.6 m). At clear cut-treatment pools, mean percent of time in the cut was 27.2 +/- 7.2% (range = 0 to 99%). Salamanders entered and crossed cuts. Buffer treatment was not significantly predictive of movement. Precipitation, season, days tracked, and distance from the pool were among the strongest predictors. Clear cuts are semi-permeable to adult spotted salamanders, but degree of permeability depends largely on precipitation patterns

Standard setting in Australian medical schools

Background: Standard setting of assessment is critical in quality assurance of medical programs. The aims of this study were to identify and compare the impact of methods used to establish the passing standard by the 13 medical schools who participated in the 2014 Australian Medical Schools Assessment Collaboration (AMSAC). Methods: A survey was conducted to identify the standard setting procedures used by participating schools. Schools standard setting data was collated for the 49 multiple choice items used for benchmarking by AMSAC in 2014. Analyses were conducted for nine schools by their method of standard setting and key characteristics of 28 panel members from four schools. Results: Substantial differences were identified between AMSAC schools that participated in the study, in both the standard setting methods and how particular techniques were implemented. The correlation between the item standard settings data by school ranged from − 0.116 to 0.632. A trend was identified for panel members to underestimate the difficulty level of hard items and overestimate the difficulty level of easy items for all methods. The median derived cut-score standard across schools was 55% for the 49 benchmarking questions. Although, no significant differences were found according to panel member standard setting experience or clinicians versus scientists, panel members with a high curriculum engagement generally had significantly lower expectations of borderline candidates (p = 0.044). Conclusion: This study used a robust assessment framework to demonstrate that several standard setting techniques are used by Australian medical schools, which in some cases use different techniques for different stages of their program. The implementation of the most common method, the Modified Angoff standard setting approach was found to vary markedly. The method of standard setting used had an impact on the distribution of expected minimally competent student performance by item and overall, with the passing standard varying by up to 10%. This difference can be attributed to the method of standard setting because the ASMSAC items have been shown over time to have consistent performance levels reflecting similar cohort ability. There is a need for more consistency in the method of standard setting used by medical schools in Australia

Nutrigenetics—Personalized Nutrition in the Genetic Age

Diet is an important modifiable determinant of disease, and it is becoming clear that diet and genetic risk factors are interactive in determining risk for diseases such as cardiovascular disease, diabetes and cancers. Advances in technology have improved our understanding of gene-nutrient interactions, and lead to the development of nutrigenetics, personalized nutrition based on genetics. While evidence is strong for some associations, others remain unclear. As such, the implementation of nutrigenetics remains controversial. While some argue it is not ready for clinical use, it has also been argued that nutrigenetics is unfairly held to a higher standard than traditional nutrition research. Despite the future promise of nutrigenetic testing for improving health outcomes, several barriers in science, technology, acceptance and ethics exist to its implementation. Gene-nutrient associations have been identified in a number of lifestyle-associated diseases, and better understanding of these relationships may lead to improved health outcomes. However, the success of nutrigenetics is not only dependent on the strength of the science, but in consumer acceptance and uptake. This narrative review provides an overview of the current landscape for nutrigenetics in relation to key disease states, and addresses the potential barriers to implementation

Interview with Victor V. Veysey

Interview in three sessions in 1993 and 1994 with Victor V. Veysey, director of Caltech's Industrial Relations Center and lecturer in business economics, 1977-1983, and Caltech alumnus (BS, 1936). He discusses his growing up in Los Angeles and Brawley (Imperial Valley), California; education at Caltech in civil engineering, then MBA at Harvard. Joins staff of Caltech's newly established Industrial Relations Center (IRC) in 1939. After outbreak of World War II he is assigned to management duties within Caltech's rocket project under leadership of Earnest Watson; involved in retrorocket, High Velocity Aircraft Rocket (HVAR), and barrage rocket programs for the navy. Concerned in later stages of the war with transfer of Caltech wartime personnel to Aerojet Corporation, the navy, and Jet Propulsion Laboratory. Involvement with Project Camel (atomic bomb housing) as assistant to Trevor Gardner. In postwar period Veysey returns to ranching in Brawley and enters local and state politics; eventually elected to California legislature (1962) and the US Congress (1970). Appointed assistant secretary of the army for civil works by President Ford in 1974. Returns to Caltech as director of the IRC, 1977; recalls IRC colleagues Robert Gray and Arthur Young, their innovative projects. Further comments on living and working in Sacramento and Washington, DC

The vitamin D–folate hypothesis as an evolutionary model for skin pigmentation: An update and integration of current ideas

© 2018 by the authors. Licensee MDPI, Basel, Switzerland. Vitamin D is unique in being generated in our skin following ultraviolet radiation (UVR) exposure. Ongoing research into vitamin D must therefore always consider the influence of UVR on vitamin D processes. The close relationship between vitamin D and UVR forms the basis of the “vitamin D–folate hypothesis”, a popular theory for why human skin colour has evolved as an apparent adaption to UVR environments. Vitamin D and folate have disparate sensitivities to UVR; whilst vitamin D may be synthesised following UVR exposure, folate may be degraded. The vitamin D–folate hypothesis proposes that skin pigmentation has evolved as a balancing mechanism, maintaining levels of these vitamins. There are several alternative theories that counter the vitamin D–folate hypothesis. However, there is significant overlap between these theories and the now known actions of vitamin D and folate in the skin. The focus of this review is to present an update on the vitamin D–folate hypothesis by integrating these current theories and discussing new evidence that supports associations between vitamin D and folate genetics, UVR, and skin pigmentation. In light of recent human migrations and seasonality in disease, the need for ongoing research into potential UVR-responsive processes within the body is also discussed

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We thank Elias and Williams for their interest in our review [...

Quantitative analysis of changes in antioxidant in crosslinked polyethylene (XLPE) cable insulation material exposed to heat and gamma radiation

Quantitative analysis of the antioxidant poly(1,2-dihydro-2,2,4-trimethylquinoline) (pTMQ) was conducted on pristine, thermally-aged, and gamma radiation-aged commercial cross-linked polyethylene-(XLPE-)based cable insulation material aged at temperatures 60, 90, and 115 °C, with gamma radiation exposure dose rates of 0, 120, 300, and 540 Gy/h for 15 days. The quantification of antioxidant was performed using pyrolysis gas chromatography-mass spectrometry (Py-GCMS). Oxidation induction time (OIT) was measured using differential scanning calorimetry (DSC) and correlation was made between the quantified depletion of antioxidant and measured OIT. It was observed that, in the case of isothermal aging, the quantity of antioxidant and OIT decreased with increasing gamma radiation dose. In the case of samples exposed to the same gamma radiation dose, the quantity of antioxidant and OIT were observed to decrease with increasing aging temperature. Depletion in the quantity of antioxidant relative to that in the pristine material ranged from 7 to 93% for differently aged samples. The measured decline in OIT ranged from 0 to 80%. Change in the quantity of antioxidant in the material was observed to follow the same trend as the change in OIT when the samples were aged under various conditions. The observations are explained in terms of the reaction between the antioxidant and free radicals created during exposure of the samples to thermal and gamma radiation