3,085 research outputs found
An initial assessment of native and invasive tunicates in shellfish aquaculture of the North American east coast
Author Posting. © The Author(s), 2010. This is the author's version of the work. It is posted here by permission of John Wiley & Sons for personal use, not for redistribution. The definitive version was published in Journal of Applied Ichthyology 26, Supple.s2 (2010): 8-11, doi:10.1111/j.1439-0426.2010.01495.x.The objective of the study was to assess the distribution of native and invasive tunicates in the fouling community of shellfish aquaculture gear along the U.S. east coast of the Atlantic. Since the 1980s, several species of invasive tunicates have spread throughout the coastal waters of the North American east coast and have become dominant fouling organisms on docks, boat hulls, mooring lines, and in shellfish aquaculture. Invasive and native tunicates negatively impact shellfish aquaculture through increased maintenance costs and reduced shellfish growth. While the presence of alien tunicates has been well documented at piers, harbors, and marinas, there are few published reports of invasive tunicate impacts to aquaculture. We surveyed shellfish aquaculture operations at Martha’s Vineyard, Massachusetts and shellfish aquaculturists in other areas along the North American east coast and report high levels of fouling caused by seven invasive, three native, and two cryptogenic species of tunicates. All study sites were fouled by one or more tunicate species. Biofouling control treatments varied among aquaculture sites and were effective in removing tunicates. Invasive and native tunicates should be considered when assessing the economic impacts of fouling organisms to the aquaculture industry.This work was funded in part by Sailors’ Snug Harbor of Boston, the Adelaide and Charles Link Foundation, and the NOAA Aquatic Invasive Species Program
Generation of ultra-short light pulses by a rapidly ionizing thin foil
A thin and dense plasma layer is created when a sufficiently strong laser
pulse impinges on a solid target. The nonlinearity introduced by the
time-dependent electron density leads to the generation of harmonics. The pulse
duration of the harmonic radiation is related to the risetime of the electron
density and thus can be affected by the shape of the incident pulse and its
peak field strength. Results are presented from numerical
particle-in-cell-simulations of an intense laser pulse interacting with a thin
foil target. An analytical model which shows how the harmonics are created is
introduced. The proposed scheme might be a promising way towards the generation
of attosecond pulses.
PACS number(s): 52.40.Nk, 52.50.Jm, 52.65.RrComment: Second Revised Version, 13 pages (REVTeX), 3 figures in ps-format,
submitted for publication to Physical Review E, WWW:
http://www.physik.tu-darmstadt.de/tqe
Drying of complex suspensions
We investigate the 3D structure and drying dynamics of complex mixtures of
emulsion droplets and colloidal particles, using confocal microscopy. Air
invades and rapidly collapses large emulsion droplets, forcing their contents
into the surrounding porous particle pack at a rate proportional to the square
of the droplet radius. By contrast, small droplets do not collapse, but remain
intact and are merely deformed. A simple model coupling the Laplace pressure to
Darcy's law correctly estimates both the threshold radius separating these two
behaviors, and the rate of large-droplet evacuation. Finally, we use these
systems to make novel hierarchical structures.Comment: 4 pages, 4 figure
Coherent control using adaptive learning algorithms
We have constructed an automated learning apparatus to control quantum
systems. By directing intense shaped ultrafast laser pulses into a variety of
samples and using a measurement of the system as a feedback signal, we are able
to reshape the laser pulses to direct the system into a desired state. The
feedback signal is the input to an adaptive learning algorithm. This algorithm
programs a computer-controlled, acousto-optic modulator pulse shaper. The
learning algorithm generates new shaped laser pulses based on the success of
previous pulses in achieving a predetermined goal.Comment: 19 pages (including 14 figures), REVTeX 3.1, updated conten
Ascidians at the Pacific and Atlantic entrances to the Panama Canal
© The Author(s), 2011. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Aquatic Invasions 6 (2011): 371-380, doi:10.3391/ai.2011.6.4.02.The Panama Canal region is susceptible to non-native species introductions due to the heavy international shipping traffic through
the area. Ascidian introductions are occurring worldwide but little is known about introductions at the Panama Canal. Surveys were
conducted in 2002, 2008, and 2009 within the Pacific and Atlantic entrances to the canal. We found a high diversity of ascidians on
both sides of the canal, dominated by non-native species; six species occurred at both Pacific and Atlantic Panama sites. This is the
first report of Polyandrocarpa anguinea and P. sagamiensis in Atlantic Panama waters and Ascidia incrassata, Ascidia sydneiensis,
Botrylloides nigrum, Botryllus planus, Didemnum perlucidum, Diplosoma listerianum, Microcosmus exasperatus, Polyandrocarpa
zorritensis, Polyclinum constellatum, Symplegma brakenhielmi, Symplegma rubra, and Trididemnum orbiculatum in Pacific Panama
waters. The canal may serve as a major invasion corridor for ascidians and should be monitored over time.Funding for
this project came from WHOI Ocean Life Institute-Tropical
Research Initiative to Carman and CNPq to Rocha
PENGARUH SALINITAS TERHADAP KELULUSAN HIDUP DAN PERTUMBUHAN BENIH IKAN BAWAL AIR TAWAR, Colossoma macropomum
The aim of this study was to know the optimal salinity level on survival and growth rates of Colossoma macropomum on larvae rearing in different salinity media. The treatment tested with six different salinities were 0; 2; 4; 6; and 10 ‰. This study was conducted from May 15 to June 12, 2006. The experiment design was arranged in completely randoumizes design with six treatments and three replications. Stock density was 1 fish/l with mean initial body weight 0.48 ± 0.03 g and initial total body length 3.04 ± 0.18 cm. The result showed that the optimal salinities between 5.74 – 6.35 ‰, which was giving growth rates 9.31 % and survival rates 100 %. On minimum salinitiy media (0 ‰) showed growth rate 5.45 % and survival rate 19.17 %
Abundance and diversity of ascidians in the southern Gulf of ChiriquĂ, Pacific Panama
© The Author(s), 2011. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Aquatic Invasions 6 (2011): 381-390, doi:10.3391/ai.2011.6.4.03.Little is known about the ascidian fauna of Pacific Panama. Ascidian surveys were conducted in the southern Gulf of Chiriquà on the Pacific coast of Panama in January 2008 and 2009. Surveys along linear transects at 2-3 m depth (snorkel, 2008) and 5 and 12 m depth (SCUBA, 2009) were conducted at multiple sites within a chain of islands extending out from the mainland. Twelve different ascidian taxa were observed with mean densities of up to ~17 ascidians m-2. The most abundant species was Rhopalaea birkelandi. Two of the most abundant taxa (Ascidia sp., Pyura sp.) appear to represent previously undescribed species. Several species of didemnids were also abundant. Ascidians were most abundant near the coast of the mainland and were less abundant near the islands farthest offshore. These data on Panamanian ascidian communities provide a baseline of local biodiversity against which it will be possible to determine whether the communities change over time, if additional species become introduced to the region, or if native Panamanian species become invasive in other parts of the world.This research was supported by Ocean Life Institute
Exploratory Grant (250513.38) to Carman and Sievert,
Tropical Research Initiative Grant (253750.09) to Carman,
Molyneaux and Sievert, a University of Hartford International
Center Faculty Grant to Bullard, and CNPq senior postdoctoral
grant to Rocha (200914/2008-1)
Expert consensus document: Mind the gaps—advancing research into short-term and long-term neuropsychological outcomes of youth sports-related concussions
Sports-related concussions and repetitive subconcussive exposure are increasingly recognized as potential dangers to paediatric populations, but much remains unknown about the short-term and long-term consequences of these events, including potential cognitive impairment and risk of later-life dementia. This Expert Consensus Document is the result of a 1-day meeting convened by Safe Kids Worldwide, the Alzheimer\u27s Drug Discovery Foundation, and the Andrews Institute for Orthopaedics and Sports Medicine. The goal is to highlight knowledge gaps and areas of critically needed research in the areas of concussion science, dementia, genetics, diagnostic and prognostic biomarkers, neuroimaging, sports injury surveillance, and information sharing. For each of these areas, we propose clear and achievable paths to improve the understanding, treatment and prevention of youth sports-related concussions
Theory of Pump Depletion and Spike Formation in Stimulated Raman Scattering
By using the inverse spectral transform, the SRS equations are solved and the
explicit output data is given for arbitrary laser pump and Stokes seed profiles
injected on a vacuum of optical phonons. For long duration laser pulses, this
solution is modified such as to take into account the damping rate of the
optical phonon wave. This model is used to interprete the experiments of Druhl,
Wenzel and Carlsten (Phys. Rev. Lett., (1983) vol. 51, p. 1171), in particular
the creation of a spike of (anomalous) pump radiation. The related nonlinear
Fourier spectrum does not contain discrete eigenvalue, hence this Raman spike
is not a soliton.Comment: LaTex file, includes two figures in LaTex format, 9 page
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