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result(s) for
"Estep, Andrew J."
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Ecological assessment of the marine ecosystems of Barbuda, West Indies: Using rapid scientific assessment to inform ocean zoning and fisheries management
by
Caselle, Jennifer E.
,
Johnson, Ayana Elizabeth
,
Richter, Lee J.
in
Abundance
,
Biodiversity
,
Biology and Life Sciences
2018
To inform a community-based ocean zoning initiative, we conducted an intensive ecological assessment of the marine ecosystems of Barbuda, West Indies. We conducted 116 fish and 108 benthic surveys around the island, and measured the abundance and size structure of lobsters and conch at 52 and 35 sites, respectively. We found that both coral cover and fish biomass were similar to or lower than levels observed across the greater Caribbean; live coral cover and abundance of fishery target species, such as large snappers and groupers, was generally low. However, Barbuda lacks many of the high-relief forereef areas where similar work has been conducted in other Caribbean locations. The distribution of lobsters was patchy, making it difficult to quantify density at the island scale. However, the maximum size of lobsters was generally larger than in other locations in the Caribbean and similar to the maximum size reported 40 years ago. While the lobster population has clearly been heavily exploited, our data suggest that it is not as overexploited as in much of the rest of the Caribbean. Surveys of Barbuda's Codrington Lagoon revealed many juvenile lobsters, but none of legal size (95 mm carapace length), suggesting that the lagoon functions primarily as nursery habitat. Conch abundance and size on Barbuda were similar to that of other Caribbean islands. Our data suggest that many of the regional threats observed on other Caribbean islands are present on Barbuda, but some resources-particularly lobster and conch-may be less overexploited than on other Caribbean islands. Local management has the potential to provide sustainability for at least some of the island's marine resources. We show that a rapid, thorough ecological assessment can reveal clear conservation opportunities and facilitate rapid conservation action by providing the foundation for a community-driven policymaking process at the island scale.
Journal Article
Benthic assemblages are more predictable than fish assemblages at an island scale
by
Kramp, Heather
,
Roach, Ty N. F
,
Hamilton, Scott L
in
Algae
,
Anthropogenic factors
,
Autocorrelation
2022
Decades of research have revealed relationships between the abundance of coral reef taxa and local conditions, especially at small scales. However, a rigorous test of covariation requires a robust dataset collected across wide environmental or experimental gradients. Here, we surveyed spatial variability in the densities of major coral reef functional groups at 122 sites along a 70 km expanse of the leeward, forereef habitat of Curaçao in the southern Caribbean. These data were used to test the degree to which spatial variability in community composition could be predicted based on assumed functional relationships and site-specific anthropogenic, physical, and ecological conditions. In general, models revealed less power to describe the spatial variability of fish biomass than cover of reef builders (R2 of best-fit models: 0.25 [fish] and 0.64 [reef builders]). The variability in total benthic cover of reef builders was best described by physical (wave exposure and reef relief) and ecological (turf algal height and coral recruit density) predictors. No metric of anthropogenic pressure was related to spatial variation in reef builder cover. In contrast, total fish biomass showed a consistent (albeit weak) association with anthropogenic predictors (fishing and diving pressure). As is typical of most environmental gradients, the spatial patterns of both fish biomass density and reef builder cover were spatially autocorrelated. Residuals from the best-fit model for fish biomass retained a signature of spatial autocorrelation while the best-fit model for reef builder cover removed spatial autocorrelation, thus reinforcing our finding that environmental predictors were better able to describe the spatial variability of reef builders than that of fish biomass. As we seek to understand spatial variability of coral reef communities at the scale of most management units (i.e., at kilometer- to island-scales), distinct and scale-dependent perspectives will be needed when considering different functional groups.
Journal Article
Contrasts in the marine ecosystem of two Macaronesian islands: A comparison between the remote Selvagens Reserve and Madeira Island
by
Clemente, Sabrina
,
Gonçalves, Emanuel João
,
Rose, Paul
in
Animals
,
Biology and Life Sciences
,
Conservation of Natural Resources
2017
The islands of Madeira and Selvagens are less than 300 km apart but offer a clear contrast between a densely populated and highly developed island (Madeira), and a largely uninhabited and remote archipelago (Selvagens) within Macaronesia in the eastern Atlantic. The Madeira Archipelago has ~260,000 inhabitants and receives over six million visitor days annually. The Selvagens Islands Reserve is one of the oldest nature reserves in Portugal and comprises two islands and several islets, including the surrounding shelf to a depth of 200 m. Only reserve rangers and a small unit of the maritime police inhabit these islands. The benthic community around Selvagens was dominated by erect and turf algae, while the community at Madeira was comprised of crustose coralline and turf algae, sessile invertebrates, and sea urchin barrens. The sea urchin Diadema africanum was 65% more abundant at Madeira than at Selvagens. Total fish biomass was 3.2 times larger at Selvagens than at Madeira, and biomass of top predators was more than 10 times larger at Selvagens. Several commercially important species (e.g., groupers, jacks), which have been overfished throughout the region, were more common and of larger size at Selvagens than at Madeira. Important sea urchin predators (e.g., hogfishes, triggerfishes) were also in higher abundance at Selvagens compared to Madeira. The effects of fishing and other anthropogenic influences are evident around Madeira. This is in stark contrast to Selvagens, which harbors healthy benthic communities with diverse algal assemblages and high fish biomass, including an abundance of large commercially important species. The clear differences between these two island groups highlights the importance of expanding and strengthening the protection around Selvagens, which harbors one of the last intact marine ecosystems in the North Atlantic, and the need to increase management and protection around Madeira.
Journal Article
Reference genome sequence of the model plant Setaria
by
Lindquist, Erika
,
Feng, Liang
,
Vaughn, Justin N
in
60 APPLIED LIFE SCIENCES
,
631/61/191
,
631/61/212/748
2012
Completion of genome sequences for the diploid
Setaria italica
reveals features of C
4
photosynthesis that could enable improvement of the polyploid biofuel crop switchgrass (
Panicum virgatum
). The genetic basis of biotechnologically relevant traits, including drought tolerance, photosynthetic efficiency and flowering control, is also highlighted.
We generated a high-quality reference genome sequence for foxtail millet (
Setaria italica
). The ∼400-Mb assembly covers ∼80% of the genome and >95% of the gene space. The assembly was anchored to a 992-locus genetic map and was annotated by comparison with >1.3 million expressed sequence tag reads. We produced more than 580 million RNA-Seq reads to facilitate expression analyses. We also sequenced
Setaria viridis
, the ancestral wild relative of
S. italica
, and identified regions of differential single-nucleotide polymorphism density, distribution of transposable elements, small RNA content, chromosomal rearrangement and segregation distortion. The genus
Setaria
includes natural and cultivated species that demonstrate a wide capacity for adaptation. The genetic basis of this adaptation was investigated by comparing five sequenced grass genomes. We also used the diploid
Setaria
genome to evaluate the ongoing genome assembly of a related polyploid, switchgrass (
Panicum virgatum
).
Journal Article
A principal components analysis of factors associated with successful implementation of an LVAD decision support tool
by
Uriel, Nir
,
Loebe, Matthias
,
Bhimaraj, Arvind
in
Cardiovascular instruments, Implanted
,
Clinical decision making
,
Decision analysis
2021
Background
A central goal among researchers and policy makers seeking to implement clinical interventions is to identify key facilitators and barriers that contribute to implementation success. Despite calls from a number of scholars, empirical insights into the complex structural and cultural predictors of why decision aids (DAs) become routinely embedded in health care settings remains limited and highly variable across implementation contexts.
Methods
We examined associations between “reach”, a widely used indicator (from the RE-AIM model) of implementation success, and multi-level site characteristics of nine LVAD clinics engaged over 18 months in implementation and dissemination of a decision aid for left ventricular assist device (LVAD) treatment. Based on data collected from nurse coordinators, we explored factors at the level of the organization (e.g. patient volume), patient population (e.g. health literacy; average sickness level), clinician characteristics (e.g. attitudes towards decision aid; readiness for change) and process (how the aid was administered). We generated descriptive statistics for each site and calculated zero-order correlations (Pearson’s
r
) between all multi-level site variables including cumulative reach at 12 months and 18 months for all sites. We used principal components analysis (PCA) to examine any latent factors governing relationships between and among all site characteristics, including reach.
Results
We observed strongest inclines in reach of our decision aid across the first year, with uptake fluctuating over the second year. Average reach across sites was 63% (s.d. = 19.56) at 12 months and 66% (s.d. = 19.39) at 18 months. Our PCA revealed that site characteristics positively associated with reach on two distinct dimensions, including a first dimension reflecting greater
organizational infrastructure and standardization
(characteristic of larger, more established clinics) and a second dimension reflecting positive
attitudinal orientations,
specifically, openness and capacity to give and receive decision support among coordinators and patients.
Conclusions
Successful implementation plans should incorporate specific efforts to promote supportive and mutually informative interactions between clinical staff members and to institute systematic and standardized protocols to enhance the availability, convenience and salience of intervention tool in routine practice. Further research is needed to understand whether “core predictors” of success vary across different intervention types.
Journal Article
The dynamical behavior of the discontinuous Galerkin method and related difference schemes
by
Stuart, Andrew M.
,
Estep, Donald J.
in
Approximation
,
Dynamical systems
,
Exact sciences and technology
2002
We study the dynamical behavior of the discontinuous Galerkin finite element method for initial value problems in ordinary differential equations. We make two different assumptions which guarantee that the continuous problem defines a dissipative dynamical system. We show that, under certain conditions, the discontinuous Galerkin approximation also defines a dissipative dynamical system and we study the approximation properties of the associated discrete dynamical system. We also study the behavior of difference schemes obtained by applying a quadrature formula to the integrals defining the discontinuous Galerkin approximation and construct two kinds of discrete finite element approximations that share the dissipativity properties of the original method.
Journal Article
Development of Resistance Mutations in Women Receiving Standard Antiretroviral Therapy Who Received Intrapartum Nevirapine to Prevent Perinatal Human Immunodeficiency Virus Type 1 Transmission: A Substudy of Pediatric AIDS Clinical Trials Group Protocol 316
by
Britto, Paula
,
Cunningham, Coleen K.
,
Gelber, Richard D.
in
Acquired Immunodeficiency Syndrome - drug therapy
,
Acquired Immunodeficiency Syndrome - prevention & control
,
AIDS
2002
Pediatric AIDS Clinical Trials Group protocol 316 was an international, multicenter, placebo-controlled trial comparing single-dose oral nevirapine (200 mg to mother and 2 mg/kg to infant) with placebo in human immunodeficiency virus (HIV)–infected pregnant women receiving standard antiretroviral therapy. This substudy evaluated the emergence of nevirapine-resistance mutations at 6 weeks postpartum in a subgroup of participants. Maternal risk factors for the emergence of nevirapine-resistance mutations were evaluated. Mutations associated with nevirapine resistance were detectable at delivery, prior to receipt of study drug, in 5 (2.3%) of 217 women. Fourteen (15%; 95% confidence interval, 8%–23%) of 95 women who received intrapartum nevirapine developed a nevirapine-resistance mutation 6 weeks postpartum. The most common mutation was K103N, which was present in 10 women. The risk for development of a new nevirapine-resistance mutation did not correlate with CD4 cell count or HIV-1 RNA load at delivery or with type of antepartum antiretroviral therapy. The risk of nevirapine resistance should be considered when determining the risks or benefits of intrapartum nevirapine in women receiving antepartum antiretroviral therapy
Journal Article
A Principal Components Analysis of Factors Associated with Successful Implementation of an LVAD Decision Support Tool
by
Volk, Robert J
,
Sulemanjee, Nasir Z
,
Jorde, Ulrich P
in
Principal components analysis
,
Success
2020
Background A central goal among researchers and policy makers seeking to implement clinical interventions is to identify key facilitators and barriers that contribute to implementation success. Despite calls from a number of scholars, empirical insights into the complex structural and cultural predictors of why DAs become routinely embedded in health care settings remains limited and highly variable across implementation contexts. Methods We examined associations between “reach”, a widely used indicator (from the RE-AIM model) of implementation success, and multi-level site characteristics of nine LVAD clinics engaged over 18 months in implementation and dissemination of a decision aid for left-ventricular assist device (LVAD) treatment. Based on data collected from nurse coordinators, we explored factors at the level of the organization (e.g. patient volume), patient population (e.g. health literacy; average sickness level), clinician characteristics (e.g. attitudes towards decision aid; readiness for change) and process (how the aid was administered). We generated descriptive statistics for each site and calculated zero-order correlations (Pearson’s r) between all multi-level site variables including cumulative reach at 12 months and 18 months for all sites. We used principal components analysis (PCA) to examine any latent factors governing relationships between and among all site characteristics, including reach. Results We observed strongest inclines in reach of our decision aid across the first year, with uptake fluctuating over the second year. Average reach across sites was 63% (s.d.=19.56) at 12 months and 66% (s.d.=19.39) at 18 months. Our (PCA) revealed that site characteristics positively associated with reach on two distinct dimensions, including a first dimension reflecting greater organizational infrastructure and standardization (characteristic of larger, more established clinics) and a second dimension reflecting positive attitudinal orientations, specifically, openness and capacity to give and receive decision support among coordinators and patients. Conclusions Successful implementation plans should incorporate specific efforts to promote supportive and mutually informative interactions between clinical staff members and to institute systematic and standardized protocols to enhance the availability, convenience and salience of intervention tool in routine practice. Further research is needed to understand whether “core predictors” of success vary across different intervention types.
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