8,138 research outputs found
An Integrated Assessment of the Introduction of Lionfish (Pterois volitans/miles complex) to the Western Atlantic Ocean.
Lionfish (Pterois volitans/miles complex) are venomous coral reef fishes from the Indian and western Pacific oceans that are now found in the western Atlantic Ocean. Adult lionfish have been observed from Miami, Florida to Cape Hatteras, North Carolina, and juvenile lionfish have been observed off North Carolina, New York, and Bermuda. The large number of adults observed and the occurrence of juveniles indicate that lionfish are established and reproducing along the southeast United States coast.
Introductions of marine species occur in many ways. Ballast water discharge, a very common method of introduction for marine invertebrates, is responsible for many freshwater fish introductions. In contrast, most marine fish introductions result from intentional stocking for fishery purposes. Lionfish, however, likely were introduced via unintentional or intentional aquarium releases, and the introduction of lionfish into United States waters should lead to an assessment of the threat posed by the aquarium trade as a vector for fish introductions.
Currently, no management actions are being taken to limit the effect of lionfish on the southeast United States continental shelf ecosystem. Further, only limited funds have been made available for research. Nevertheless, the extent of the introduction has been documented and a forecast of the maximum potential spread of lionfish is being developed. Under a scenario of no management actions and limited research, three predictions are made:
● With no action, the lionfish population will continue to grow along the southeast United States shelf.
● Effects on the marine ecosystem of the southeast United States will become more noticeable as the lionfish population grows.
● There will be incidents of lionfish envenomations of divers and/or fishers along the east coast of the United States.
Removing lionfish from the southeast United States continental shelf ecosystem would be expensive and likely impossible. A bounty could be established that would encourage the removal of fish and provide specimens for research. However, the bounty would need to be lower than the price of fish in the aquarium trade (~50 each) to ensure that captured specimens were from the wild. Such a low bounty may not provide enough incentive for capturing lionfish in the wild. Further, such action would only increase the interaction between the public and lionfish, increasing the risk of lionfish envenomations.
As the introduction of lionfish is very likely irreversible, future actions should focus on five areas. 1) The population of lionfish should be tracked. 2) Research should be conducted so that scientists can make better predictions regarding the status of the invasion and the effects on native species, ecosystem function, and ecosystem services. 3) Outreach and education efforts must be increased, both specifically toward lionfish and more generally toward the aquarium trade as a method of fish introductions. 4) Additional regulation should be considered to reduce the frequency of marine fish introduction into U.S. waters. However, the issue is more complicated than simply limiting the import of non-native species, and these complexities need to be considered simultaneously. 5) Health care providers along the east coast of the United States need to be notified that a venomous fish is now resident along the southeast United States.
The introduction and spread of lionfish illustrates the difficulty inherent in managing introduced species in marine systems. Introduced species often spread via natural mechanisms after the initial introduction. Efforts to control the introduction of marine fish will fail if managers do not consider the natural dispersal of a species following an introduction. Thus, management strategies limiting marine fish introductions need to be applied over the scale of natural ecological dispersal to be effective, pointing to the need for a regional management approach defined by natural processes not by political boundaries.
The introduction and success of lionfish along the east coast should change the long-held perception that marine fish invasions are a minimal threat to marine ecosystems. Research is needed to determine the effects of specific invasive fish species in specific ecosystems. More broadly, a cohesive plan is needed to manage, mitigate and minimize the effects of marine invasive fish species on ecosystems that are already compromised by other human activities. Presently, the magnitude of marine fish introductions as a stressor on marine ecosystems cannot be quantified, but can no longer be dismissed as negligible.
(PDF contains 31 pages
Classifying Cantor Sets by their Fractal Dimensions
In this article we study Cantor sets defined by monotone sequences, in the
sense of Besicovitch and Taylor. We classify these Cantor sets in terms of
their h-Hausdorff and h-Packing measures, for the family of dimension functions
h, and characterize this classification in terms of the underlying sequences.Comment: 10 pages, revised version. To appear in Proceedings of the AMS
Cross-shelf and seasonal variation in larval fish assemblages on the southeast United States continental shelf off the coast of Georgia
Seasonal and cross-shelf patterns were investigated in larval fish assemblages on the continental shelf off the coast of Georgia. The influence of environmental factors on
larval distributions also was examined, and larval transport processes on the shelf were considered. Ichthyoplankton and environmental data were collected approximately every other month from spring 2000 to winter
2002. Ten stations were repeatedly sampled along a 110-km cross-shelf transect, including four stations in the vicinity of Gray’s Reef National Marine Sanctuary. Correspondence analysis (CA) on untransformed community
data identified two seasonal (warm weather [spring, summer, and fall] and winter) and three cross-shelf larval assemblages (inner-, mid-, and outer-shelf ). Five environmental factors (temperature, salinity, density,
depth of the water column, and stratification) were related to larval cross-shelf distribution. Specifically,
increased water column stratification was associated with the outer-shelf assemblage in spring, summer, and fall. The inner shelf assemblage was associated with generally lower temperatures and lower salinities in the spring and summer and higher salinities in the winter. The three cross-shelf
regions indicated by the three assemblages coincided with the location of three primary water masses on the shelf. However, taxa occurring together within an assemblage were
transported to different parts of the shelf; thus, transport across the continental shelf off the coast of Georgia cannot be explained solely by twodimensional
physical factors
Effect of type of otolith and preparation technique on age estimation of larval and juvenile spot (Leiostomus xanthurus)
Otoliths of larval and juvenile fish provide a record of age, size, growth, and development (Campana and Neilson,
1985; Thorrold and Hare, 2002). However, determining the time of first increment formation in otoliths (Campana, 2001) and assessing the accuracy (deviation from real age)
and precision (repeatability of increment counts from the same otolith) of increment counts are prerequisites for using otoliths to study the life history of fish (Campana and Moksness, 1991). For most fish species, first increment deposition occurs either at hatching, a day after hatching, or after first feeding and yolksac absorption (Jones, 1986; Thorrold and Hare, 2002). Increment deposition before
hatching also occurs (Barkmann and Beck, 1976; Radtke and Dean, 1982). If first increment deposition does not occur at hatching, the standard procedure is to add a predetermined number to increment counts to estimate fish age (Campana and Neilson, 1985)
Relationships between Larval and Juvenile Abundance of Winter-Spawned Fishes in North Carolina, USA
We analyzed the relationships between the larval and juvenile abundances of selected estuarine-dependent fishes that spawn during the winter in continental shelf waters of the U.S. Atlantic coast. Six species were included in the analysis based on their ecological and economic importance and relative abundance in available surveys: spot Leiostomus xanthurus, pinfish Lagodon rhomboides, southern flounder Paralichthys lethostigma, summer flounder Paralichthys dentatus, Atlantic croaker Micropogonias undulatus, and Atlantic menhaden Brevoortia tyrannus. Cross-correlation analysis was used to examine the relationships between the larval and juvenile abundances within species. Tests of synchrony across species were used to find similarities in recruitment dynamics for species with similar winter shelf-spawning life-history strategies. Positive correlations were found between the larval and juvenile abundances for three of the six selected species (spot, pinfish, and southern flounder). These three species have similar geographic ranges that primarily lie south of Cape Hatteras. There were no significant correlations between the larval and juvenile abundances for the other three species (summer flounder, Atlantic croaker, and Atlantic menhaden); we suggest several factors that could account for the lack of a relationship. Synchrony was found among the three southern species within both the larval and juvenile abundance time series. These results provide support for using larval ingress measures as indices of abundance for these and other species with similar geographic ranges and winter shelf-spawning life-history strategies
Juvenile fish assemblages collected on unconsolidated sediments of the southeast United States continental shelf
This paper is not subject to U.S. copyright. The definitive version was published in Fishery Bulletin 104 (2006): 256-277.Patterns were investigated in juvenile fish use of unconsolidated sediments on the southeast United States continental shelf off Georgia. Juvenile fish and environmental data
were sampled at ten stations along a
110-km cross-shelf transect, including
four stations surrounding Gray’s Reef
National Marine Sanctuary (Gray’s
Reef NMFS). Cross-shelf stations
were sampled approximately quarterly
from spring 2000 to winter 2002.
Additional stations were sampled on
three transects inshore of Gray’s Reef
NMS and four transects offshore of
the Sanctuary during three cruises
to investigate along-shelf patterns in
the juvenile fish assemblages. Samples
were collected in beam trawls,
and 121 juvenile taxa, of which 33
were reef-associated species, were
identif ied. Correspondence analysis
on untransformed juvenile fish
abundance indicated a cross-shelf
gradient in assemblages, and the
station groupings and assemblages
varied seasonally. During the spring,
fall, and winter, three cross-shelf
regions were identified: inner-shelf,
mid-shelf, and outer-shelf regions. In
the summer, the shelf consisted of a
single juvenile fish assemblage. Water
depth was the primary environmental
variable correlated with cross-shelf
assemblages. However, salinity, density,
and water column stratification
also correlated with the distribution
of assemblages during the spring, fall,
and winter, and along with temperature
likely inf luenced the distribution
of juvenile fish. No along-shelf
spatial patterns were found in the
juvenile fish assemblages, but the
along-shelf dimension sampled was
small (~60 km). Our results revealed
that a number of commercially and
recreationally important species used
unconsolidated sediments on the shelf
off Georgia as juvenile habitat. We
conclude that management efforts
would be improved through a greater
recognition of the importance of these
habitats to fish production and the
interconnectedness of multiple habitats
in the southeast U.S. continental
shelf ecosystem.Gray’s Reef National Marine Sanctuary,
the National Marine Sanctuary Office, and Center for Coastal Fisheries and Habitat Research provided funding for the project
Scaling Professional Development: Integrity of Implementation as a Measurement Approach
Professional learning about an innovative teaching method is a demonstrated way to improve teacher practices, and ultimately impact student learning. One way to scale up professional learning is a facilitator development model, in which professional learning and development (PLD) designers prepare facilitators to understand the innovation and they in turn, teach teachers. To understand the effectiveness of this model, identifying how facilitators implement the model with teachers is critical. As such, the Power of Data (POD) team scaled-up effective PLD by providing Facilitation Academies to teach others to facilitate POD Teacher Workshops (TWs). The expectation was that changes based on local contexts would occur; thus, we focused on Integrity of Implementation (IOI) rather than fidelity of implementation. A measurement approach for IOI was created to understand how facilitators (n=13) delivered TWs and how they retained or modified the program principles. Examples from this project illustrate how a robust IOI measurement approach based on a variety of data sources can inform the design of PLD experiences, enable understanding of teacher PLD experiences, and allow researchers to determine whether the scaled-up model is effective
Charge injection instability in perfect insulators
We show that in a macroscopic perfect insulator, charge injection at a
field-enhancing defect is associated with an instability of the insulating
state or with bistability of the insulating and the charged state. The effect
of a nonlinear carrier mobility is emphasized. The formation of the charged
state is governed by two different processes with clearly separated time
scales. First, due to a fast growth of a charge-injection mode, a localized
charge cloud forms near the injecting defect (or contact). Charge injection
stops when the field enhancement is screened below criticality. Secondly, the
charge slowly redistributes in the bulk. The linear instability mechanism and
the final charged steady state are discussed for a simple model and for
cylindrical and spherical geometries. The theory explains an experimentally
observed increase of the critical electric field with decreasing size of the
injecting contact. Numerical results are presented for dc and ac biased
insulators.Comment: Revtex, 7pages, 4 ps figure
Community pharmacy-based medication therapy management services: financial impact for patients
This is the published version. Copyright 2012 Centro de Investigaciones y Publicaciones Farmaceuticas.Objective: To determine the direct financial impact
for patients resulting from Medication Therapy
Management (MTM) interventions made by
community pharmacists. Secondary objectives
include evaluating the patient and physician
acceptance rates of the community pharmacists’
recommended MTM interventions.
Methods: This was a retrospective observational
study conducted at 20 Price Chopper and Hen
House grocery store chain pharmacies in the
Kansas City metro area from January 1, 2010 to
December 31, 2010. Study patients were Medicare
Part D beneficiaries eligible for MTM services. The
primary outcome was the change in patient out-ofpocket
prescription medication expense as a result
of MTM services.
Results: Of 128 patients included in this study, 68%
experienced no out-of-pocket financial impact on
their medication expenses as a result of MTM
services. A total of 27% of the patients realized a
cost-savings (USD440.50 per year, (SD=289.69))
while another 5% of patients saw a cost increase in
out-of-pocket expense (USD255.66 per year,
(SD=324.48)). The net financial impact for all 128
patients who participated in MTM services was an
average savings of USD102.83 per patient per year
(SD=269.18, p<0.0001). Pharmacists attempted a
total of 732 recommendations; 391 (53%) were
accepted by both the patient and their prescriber. A
total of 341 (47%) recommendations were not
accepted because of patient refusal (290, 85%) or
prescriber refusal (51, 15%).
Conclusions: Patient participation in MTM services
reduces patient out-of-pocket medication expense.
However, this savings is driven by only 32% of
subjects who are experiencing a financial impact on
out-of-pocket medication expense. Additionally, the
majority of the pharmacists’ recommended
interventions (53%) were accepted by patients and
prescribers
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