2,212 research outputs found
Oyster reef ecosystem services: Macrofauna utilization of restored oyster reefs - Harris Creek, Maryland, USA
Oyster reefs provide habitat for a variety of macrofauna species. Our studies focused on the relationship between oyster tissue biomass density and reef-associated macrofauna biomass density. Studies were conducted in 2015-2017 and sites encompassed the majority of the area in which restoration activities were conducted with the Harris Creek Oyster Sanctuary in Maryland. Results presented in this report focus on: 1) interactions between oyster biomass density and season in determining macrofauna biomass, 2) responses of macrofauna to oyster biomass densities below “threshold” levels (0-14.9 g DW m-2) and between threshold and “target” levels (15-49.9 g DW m-2) defined in the success metrics for the Harris Creek restoration effort, 3) the role of tray-scale (0.1 m2), plot-scale (10 m2), and reef-scale oyster biomass density in determining associated macrofauna biomass, and 4) larger scale patterns in macrofauna biomass density within the creek
A Comparison Of Crassostrea Virginica And C. Ariakensis In Chesapeake Bay: Does Oyster Species Affect Habitat Function?
We examined the possibility that a nonnative oyster species would provide an ecologically functional equivalent of the native oyster species if introduced into the Chesapeake Bay. Habitat complexity and associated benthic communities of experimental triploid Crassostrea virginica and Crassostrea ariakensis reefs were investigated at 4 sites of varying salinity, tidal regime, water depth, predation intensity, and disease pressure in the Chesapeake Bay region (Maryland and Virginia). Four experimental treatments were established at each site: C. virginica, C. ariakensis, 50:50 of C. virginica and C. ariakensis, and shell only. Abundance, biomass, species richness, evenness, dominance, and diversity of reef-associated fauna were evaluated in relation to habitat location and oyster species. Although habitat complexity varied with location, no differences among complexity were associated with oyster species. Similarly, differences in faunal assemblages were more pronounced between sites than within sites. Our results show functional equivalency between oyster species with respect to habitat at the intertidal site and the low-salinity subtidal location. At subtidal sites of higher salinity, however, the numbers of organisms associated with C. virginica reefs per unit of oyster biomass were significantly greater than the numbers of organisms associated with C. ariakensis reefs. Multivariate analyses of data from subtidal high-salinity sites revealed unique communities associated with C. virginica treatments, whereas mixed-oyster species assemblages were functionally equivalent to monospecific C. ariakensis experimental treatments. Our study represents the first effort to quantify the potential habitat function of C. ariakensis, which has been proposed for an intentional introduction into Chesapeake Bay, and provides evidence of species-specific similarities and differences in reef-associated communities
Landscape Transformation During Ceramic Age and Colonial Occupations of Barbuda, West Indies
This research documented the history of landscape transformation on the island of Barbuda in the Lesser Antilles, Caribbean through cross-disciplinary research approaches. Excavations confirmed a human presence for the seasonal exploitation of conch meat and other mollusks during the Archaic Age (c.3000–500 BC), but more substantial impacts to terrestrial ecosystems likely began during the Ceramic Age (c.500 BC–AD 1500). Our combined sedimentary and charcoal records revealed that human-induced environmental transformations began with Ceramic Age peoples as they cleared vegetation for settlements and gardens with intentional burning. Sedimentary charcoal indicated a dramatic decline in fire during post-Ceramic Age abandonment, continuing through the Colonial Period, as the dominant human activities shifted to herding, farming, and selective wood harvesting. Historical sources showed that during the Colonial Period (post-1492), the island was intermittently settled until the mid-seventeenth century, while the Codrington family of Antigua held the lease to the island from 1681 to 1870. They used the island for farming and stock-rearing, exporting meat and draught animals along with lime, timber, and subsistence crops. Macrocharcoal recovered from Colonial Period archaeological sites reflect the use of a variety of local species and wood imported to the island or harvested from shipwrecks
Survival And Growth Of Triploid Crassostrea Virginica (Gmelin, 1791) And C-Ariakensis (Fujita, 1913) In Bottom Environments Of Chesapeake Bay: Implications For An Introduction
Survival and growth of triploid Crassostrea virginica and triploid C. ariakensis were investigated at four sites Surrounding Chesapeake Bay, United States, that varied tried in salinity, tidal regime, water depth, predation intensity and disease pressure. Four experimental treatments were established at each site: C. virginica; C. ariakensis; 50:50 of C. virginica: C. ariakensis: and shell only. Oysters were deployed at mean shell heights of 12.80 min and 13.85 mm (C. virginica and C. ariakensis, respectively), at an overall density of 347.5 oysters m(-2). Oyster survival and growth varied significantly, with site and species. Survival was significantly higher in C. virginica than C. ariakensis at the intertidal site, and significantly higher in C. ariakensis than C. virginica at the highest salinity, subtidal site. Survival did not differ significantly between species at the mid and low salinity, subticial sites. For both Species. survival differed significantly between sites, with lowest survival in both species Occurring Lit the intertidal site. Among the subtidal sites. C. virginica survival varied inversely with salinity, whereas C. ariakensis had the lowest Survival at the mid salinity site. Eight months after deployment C. ariakensis were significantly, larger than C. virginica at all sites. This difference generally persisted throughout the experiment, though the size differences between oyster species at the lowest salinity site were small (\u3c 10%). Shell heights within single-species treatments differed significantly between sites; highest growth rates were observed at the high salinity, subtidal site, whereas lowest growth rates were observed at the high salinity, intertidal site. At low and mid salinity subtidal sites, C. ariakensis shell heights were significantly greater in the single-species treatment compared with the mixed-species treatment. Perkinsus marinus infections occurred in both species at all sites, with prevalences varying between sites. In C. virginica, moderate and high intensity infections were only common at the two higher salinity sites, whereas infections in C. ariakensis were generally low, to rare. Haplosporidium nelsoni infections in C. virginica were only observed at the two higher salinity sites and prevalences were generally low. Two out of 53 C. ariakensis tested at the high salinity, subtidal site had rare H. nelsoni infections. Bonamia spp. infections were never observed. Our study supports previous laboratory findings and observations from its native range that C. ariakensis Survives poorly in intertidal habitats. In subtidal habitats, however, C. ariakensis displayed broad environmental tolerances, often exceeding native oyster Survival and growth rates. Post-introduction C. ariakensis Populations would be shaped by the survival and growth patterns described here, but also by their reproductive success, larval Survival, predator-prey interactions and prevailing disease dynamics
Sexual victimization in sin city
ABSTRACT Las Vegas, Nevada sells sex without much discussion of the potential negative consequences to this overtly sexual environment. This paper will look at rates of sexual assault in this self-described adult playground. Criminal justice professionals in Las Vegas acknowledge struggling with elevated rates of sexual victimization. Assault rates were considered through multiple sources of data. Federal data suggests that Las Vegas has high rates for a city of its size, higher than other cities with a similar focus on tourism. Sexual victimization reported at the college level was also higher than seen at other campuses, suggesting that the risk of victimization is city wide. The sex drive of college students in Las Vegas was also examined
Integrated assessment of oyster reef ecosystem services: Macrofauna utilization of restored oyster reefs
Within the Harris Creek Oyster Sanctuary in the Maryland portion of Chesapeake Bay, we evaluated relationships between basic oyster reef characteristics and the abundance and biomass of macrofauna. The eight sites selected for these studies included five restored oyster reef sites and three sites suitable for restoration that had not been restored. These sites encompassed a range of oyster biomass density and were spread throughout the sanctuary area. At each site one month prior to each of four sampling periods, divers filled four wire mesh baskets (0.1m2 surface area x 15 cm depth) with material from the site and embedded them so that the surface was flush with the surrounding substratum. In spring, early summer, late summer and fall of 2015, divers collected baskets and returned them to the laboratory where all macrofauna ≥1 mm were collected from each sample and their identity, abundance and biomass were determined. In addition to the abundance and biomass of oysters, we also assessed the amount of surface as the volume of live oysters along with that of any oyster shells whose surface was at least 50% oxic based on coloration (i.e. black shell was presumed to have been buried below the surface in anoxic conditions).
Positive relationships were identified for all three reef characteristics and the three major macrofaunal groups examined. In the majority of seasons, the relationship between both biomass and abundance of the hooked mussel, Ischadium recurvum, as a power function of oyster tissue biomass density, oyster abundance per square meter and surface shell volume. The relationship between oyster reef characteristics and the biomass and abundance of the mud crab, Eurypanopeus depressus, and of the naked goby, Gobiosoma bosc, were always positive but were more variable than that for I. recurvum. These data demonstrate that relationships can be found between oyster reef characteristics and macrofauna abundance and biomass. They further demonstrate that, in many cases, simple measures of reef characteristics such as oyster abundance and shell volume can provide predictions of macrofauna abundance and biomass that are comparable to more labor intensive measures such as oyster tissue biomass
Integrated assessment of oyster reef ecosystem services: Fish and crustacean utilization and trophic linkages
Using a regression design that encompassed the continuum of oyster reef biomass density in Harris Creek, MD, from unrestored reefs to those restored reefs with the greatest oyster biomass, we examined finfish and crustacean utilization of these habitats. Of the eight sites studied, three had not been subject to any restoration activities and five had been planted in 2012 with juvenile oysters set on oyster shell. All sites were sampled in April, June, August, and October 2015. During each sampling period, we assessed abundance, total length and biomass of finfish and examined gut contents to assess the diets of selected finfish species. Of the species collected that were likely to use reefs as habitat or a foraging ground, only striped bass and white perch were sufficiently abundant to support robust statistical analyses. Regression analyses found no clear relationship between oyster biomass density and catch per unit effort, total length or biomass for striped bass or white perch. Analyses of the effects of sampling period and restoration status (restored versus non-restored sites) on fish utilization frequently found an effect of sampling period but rarely found an effect of restoration status. In all cases where differences were detected, they suggested greater utilization of non-restored sites. Overall, data were sparse and the power of statistical analyses was low. Analyses of striped bass and white perch diets suggest that they are using oyster reefs as a foraging ground. Although comparisons of the proportion of striped bass and white perch that contained prey in their stomachs found no difference between those caught on restored sites versus non-restored sites, gut contents of both species contained prey taxa that are likely more abundant on restored oyster reefs than nonrestored sites. As a percentage of total prey wet weight, polychaete worms were the most important component of striped bass diets in both April (50%) and August (47%). Of the polychaete worms identifiable to species, 100% were Alitta succinea, a species found in much greater abundance and biomass on restored oyster reefs than on comparable non-restored sites (Kellogg et al. 2013, Rodney and Paynter 2006). White perch diets were dominated by the ascidian Molgula manhattensis (52%), a species generally found in greater abundance on hard substrates including oyster reefs. Of the identifiable species of fish found in the stomachs of striped bass, 93% by weight were naked gobies (Gobiosoma bosc) or striped blennies (Chasmodes bosquianus), two species found in greater abundance and biomass on restored oyster reefs than nonrestored sites in Chesapeake Bay (Kellogg et al. 2013, Rodney and Paynter 2006). For white perch, naked gobies accounted for 95% of the identifiable fish species by weight. Direct comparisons of white perch and striped bass diets to the prey fields at each sampling site will be conducted as part of a companion project also funded by NOAA Chesapeake Bay Office (Award #: NA13NMF4570209: Integrated assessment of oyster reef ecosystem services: Macrofaunal utilization, secondary production and nutrient sequestration). This companion project will also provide data on abundance, biomass and distribution of small, reef-associated species including naked gobies, striped blennies, and oyster toadfish (Opsanus tau)
A scoping review of nurse-led randomised controlled trials
Background: Nurses comprise the largest portion of the healthcare workforce worldwide. However, nurse representation in the leadership of clinical research and research funding is largely unknown. The Australasian Nursing and Midwifery Clinical Trials Network was established to provide a coordinated network, focussed on building research capacity in nursing and midwifery. To support this work, this scoping review of nurse-led randomised controlled trials was conducted to summarise research activity, as well as highlight future research directions, gaps and resources. Midwife-led trials will be reported elsewhere. Aim: To quantify number, type and quality of nurse-led randomised controlled trials registered between 2000–2021. Design: A scoping review of RCTs. Data Sources: Medline, Emcare and Scopus were searched from 2000 to August 2021. ANZCTR, NHMRC, MRFF and HRC (NZ) registries were searched from inception to July 2021. Review Methods: This review was informed by the JBI scoping review framework using the PRISMA-ScR. Results: Our search yielded 186 nurse-led publications and 279 registered randomised controlled trials. Multiple trials had the same nurse leaders. There were more registrations than publications. Publications were predominantly of high methodological quality; however, there was a reliance on active controls and blinding low. Trial registrations indicate that universities and hospital/healthcare organisations were the major sources of funding, while publications indicate that Governments and the National Health and Medical Research Council were the main funding bodies. Conclusion: A small number of high-quality, large-scale, nationally funded randomised controlled trials were identified, with a larger number of locally funded small trials. There was a disparity between the number of registered trials and those published. Additional infrastructure, funding and career frameworks are needed to enable nurses to design, conduct and publish clinical trials that inform the health system and improve health outcomes. Relevance to Clinical Practice: Research initiated and led by nurses has the potential to improve the health and well-being of individuals and communities, and current nurse-led research is of high methodological quality; however, there were very few nurse-led RCTs, conducted by a small pool of nurse researchers. This gap highlights the need for support in the design, conduct and publishing of nurse-led RCTs. Patient or Public Contribution: This is a scoping review; therefore, patient or public contribution is not applicable
Subjective assessment of listening environments in university classrooms: Perceptions of students,"
A questionnaire is developed to evaluate perception of the listening environment by university students. The objectives were to develop a questionnaire-based measurement tool, derive a measure of perceived classroom-listening quality, use the questionnaire to investigate factors that enhance, impair, or do not affect perceived listening quality, and consider the implications for classroom design. The questionnaire was administered to over 5700 students in 30 classrooms at one university. Physical and acoustical measurements were also performed in each classroom. The questionnaire included items that recorded aspects of student perception, as well as individual, course-, and instructor-specific factors. Responses to 19 perception items generated a perception of listening ease Í‘PLEÍ’ score for each student and a classroom-average score. Decreased PLE was associated with women, English-second-language students, those with hearing impairment, students not interested in the course material, and those who found the material difficult. Increased PLE was associated with higher speech transmission index, acceptable lighting, temperature and seating, better instructor voice, increased visual-aid use, and easier course material. Results indicate that PLE is a useful measure of student perception of the classroom-listening environment, and that optimal classroom acoustical design must take into consideration "in-use" conditions, as well as classroom physical characteristics
- …