2,057 research outputs found
Thrilling Tales of the Tuscania - From the Rolling Deep
All good stories should have an introduction, and as the collaborators wrote distinct accounts of the sinking of the Tuscania, it is necessary to harmonize the stories somewhat. It was the original intention of the editor to combine the separate narratives of the authors into a single story, but each was distinct enough to merit printing entire. Suffice to say that each got off the boat alright, which seemed to be the principal object in view at the time. The editor met Shorty Hoyer a month or so later and he was very willingly chopping wood in France. Nevertheless, we are proud of the fact that we had five Ames foresters on the Tuscania and are more than glad that they are still with us. -Editor’s Note
Evaluation of macrophyte control in 38 Florida lakes using triploid grass carp
Florida’s large number of shallow lakes, warm climate and
long growing season have contributed to the development of
excessive growths of aquatic macrophytes that have seriously
interfered with many water use activities. The introduction
of exotic aquatic macrophyte species such as hydrilla (
Hydrilla
verticillata
) have added significantly to aquatic plant problems
in Florida lakes. The use of grass carp (
Ctenopharyngodon
idella
) can be an effective and economical control for aquatic
vegetation such as hydrilla. Early stocking rates (24 to 74
grass carp per hectare of lake area) resulted in grass carp
consumption rates that vastly exceeded the growth rates of
the aquatic plants and often resulted in the total loss of all
submersed vegetation. This study looked at 38 Florida lakes
that had been stocked with grass carp for 3 to 10 years with
stocking rates ranging from < 1 to 59 grass carp per hectare
of lake and 1 to 207 grass carp per hectare of vegetation to
determine the long term effects of grass carp on aquatic macrophyte
communities. The median PAC (percent area coverage)
value of aquatic macrophytes for the study lakes after
they were stocked with grass carp was 14% and the median
PVI (percent volume infested) value of aquatic macrophytes
was 2%. Only lakes stocked with less than 25 to 30 fish per
hectare of vegetation tended to have higher than median
PAC and PVI values. When grass carp are stocked at levels of
> 25 to 30 fish per hectare of vegetation the complete control
of aquatic vegetation can be achieved, with the exception of
a few species of plants that grass carp have extreme difficulty
consuming. If the management goal for a lake is to control
some of the problem aquatic plants while maintaining a
small population of predominately unpalatable aquatic
plants, grass carp can be stocked at approximately 25 to 30
fish per hectare of vegetation
Nutrient Limitation of Periphyton in a Spring-Fed, Coastal Stream in Florida, USA.
There is strong evidence to suggest that ground-water
nitrate concentrations have increased in recent years and
further increases are expected along portions of the central
Gulf coast of Florida. Much of the nitrate enriched groundwater
is discharged into surface waters through numerous
freshwater springs that are characteristic of the area and the
potential for eutrophication of their receiving waters is a
legitimate concern. To test the potential effects of elevated
nutrient concentrations on the periphyton community an
in
situ
nutrient addition experiment was conducted in the
spring-fed Chassahowitzka River, FL, USA, during the summer
of 1999. Plastic tubes housing arrays of glass microscope
slides were suspended in the stream. Periphyton colonizing
the microscope slides was subjected to artificial increases in
nitrogen, phosphorus or a combination of both. Slides from
each tube were collected at 3- to 4- day intervals and the
periphyton communities were measured for chlorophyll concentration.
The addition of approximately 10 μg/L of phosphate
above ambient concentrations significantly increased
the amount of periphyton on artificial substrates relative to
controls; the addition of approximately 100 μg/L of nitrate
above ambient concentrations did not. The findings from
this experiment implicated phosphorus, rather than
nitrogen, as the nutrient that potentially limits periphyton
growth in this system.(PDF contains 4 pages.
Rapid self-assembly of α-synuclein observed by in situ atomic force microscopy
Self-assembly of α−synuclein resulting in protein aggregates of diverse morphology has been implicated in the pathogenesis of Parkinson’s disease and other neurodegenerative disorders known as synucleinopathies. Apart from its biomedical relevance, this aggregation process is representative of the interconversion of an unfolded protein into nanostructures with typical amyloid features. We have used in situ tapping mode atomic force microscopy (AFM) to continuously monitor the self-assembly of wild-type α-synuclein, its disease-related mutants A30P and A53T, and the C-terminally truncated variant α-synuclein(1-108). Different aggregation modes were observed depending on experimental conditions, i.e. pH, protein concentration, polyamine concentration, temperature and the supporting substrate. At pH 7.5, in the absence of the biogenic polyamines spermidine or spermine, elongated sheets 1.1(±0.2)nm in height and presumably representing individual β-sheet structures, were formed on mica substrates within a few minutes. Their orientation was directed by the crystalline substructure of the substrate. In contrast, sheet formation was not observed with hydrophobic highly oriented pyrolytic graphite (HOPG) substrates, suggesting that negatively charged surfaces promote α-synuclein self-assembly. In the presence of spermidine or spermine 5.9(±1.0) nm high spheroidal structures were preferentially formed, sharing characteristics with similar structures previously reported for several amyloidogenic proteins and linked to neurotoxicity. Alpha-synuclein spheroid formation depended critically on polyamine binding to the Cterminus, revealing a promoting effect of the C-terminus on α-synuclein assembly in the bound state. In rare cases, fibril growth from spheroids or preformed aggregates was observed. At pH 5.0, fibrils were formed initially and incorporated into amorphous aggregates in the course of the aggregation process, providing evidence for the potential of amyloid fibril surfaces to act as nucleation sites in amorphous aggregation. This study provides a direct insight into different modes of α-synuclein self-assembly and identifies key factors modulating the aggregation process
Photoluminescence and Terahertz Emission from Femtosecond Laser-Induced Plasma Channels
Luminescence as a mechanism for terahertz emission from femtosecond
laser-induced plasmas is studied. By using a fully microscopic theory, Coulomb
scattering between electrons and ions is shown to lead to luminescence even for
a spatially homogeneous plasma. The spectral features introduced by the rod
geometry of laser-induced plasma channels in air are discussed on the basis of
a generalized mode-function analysis.Comment: 4 pages with 2 figures
An infrared study of the double nucleus in NGC3256
We present new resolved near and mid-IR imaging and N-band spectroscopy of
the two nuclei in the merger system NGCA3256, the most IR luminous galaxy in
the nearby universe. The results from the SED fit to the data are consistent
with previous estimates of the amount of obscuration towards the nuclei and the
nuclear star formation rates. However, we also find substantial differences in
the infrared emission from the two nuclei which cannot be explained by
obscuration alone. We conclude that the northern nucleus requires an additional
component of warm dust in order to explain its properties. This suggests that
local starforming conditions can vary significantly within the environment of a
single system.Comment: Accepted for publication (MNRAS
Kunst und Kunstgeschichte in der deutschen Tagespresse 1950 - 2000
In dieser Dissertation wird untersucht, wie Themen rund um Kunst und Kunstgeschichte in der deutschen Tagespresse dargestellt werden. Anhand einer Untersuchung der vier bedeutendsten Zeitungen Deutschlands, der Frankfurter Allgemeinen Zeitung, der Frankfurter Rundschau, der Süddeutschen Zeitung und der Welt, wird aufgezeigt, welche Entwicklung das kunstgeschichtliche Feuilleton im Zeitraum von 1950 bis 2000 nimmt. In diesem Zusammenhang werden quantitative und qualitative Unterschiede und somit die den Leser am effektivsten informierende Zeitung ausgemacht. Zudem wird der Blick auf die ausländischen Feuilletons und auf die Erfahrungen eines Kunstredakteurs gelenkt. In ausgesuchten Jahrgängen wird dokumentiert, auf welch mannigfaltige Weise eine Zeitung informieren kann und welche Rolle die Kunst im deutschen Feuilleton spielt
Quality of Web Mashups: A Systematic Mapping Study
The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-319-04244-2_8Web mashups are a new generation of applications based on the
composition of ready-to-use, heterogeneous components. They are gaining
momentum thanks to their lightweight composition approach, which represents
a new opportunity for companies to leverage on past investments in SOA, Web
services, and public APIs. Although several studies are emerging in order to
address mashup development, no systematic mapping studies have been
reported on how quality issues are being addressed. This paper reports a
systematic mapping study on which and how the quality of Web mashups has
been addressed and how the product quality-aware approaches have been
defined and validated. The aim of this study is to provide a background in
which to appropriately develop future research activities. A total of 38 research
papers have been included from an initial set of 187 papers. Our results
provided some findings regarding how the most relevant product quality
characteristics have been addressed in different artifacts and stages of the
development process. They have also been useful to detect some research gaps,
such as the need of more controlled experiments and more quality-aware
mashup development proposals for other characteristics which being important
for the Web domain have been neglected such as Usability and ReliabilityThis work is funded by the MULTIPLE project (TIN2009-13838), the Senescyt program (scholarships 2011), and the Erasmus Mundus Programme of the European Commission under the Transatlantic Partnership for Excellence in Engineering - TEE Project.Cedillo Orellana, IP.; Fernández MartÃnez, A.; Insfrán Pelozo, CE.; Abrahao Gonzales, SM. (2013). Quality of Web Mashups: A Systematic Mapping Study. En Current Trends in Web Engineering. Springer. 66-78. https://doi.org/10.1007/978-3-319-04244-2_8S6678Alkhalifa, E.: The Future of Enterprise Mashups. Business Insights. E-Strategies for Resource Management Systems (2009)Beemer, B., Gregg, D.: Mashups: A Literature Review and Classification Framework. Future Internet 1, 59–87 (2009)Cappiello, C., Daniel, F., Matera, M.: A Quality Model for Mashup Components. In: Gaedke, M., Grossniklaus, M., DÃaz, O. (eds.) ICWE 2009. LNCS, vol. 5648, pp. 236–250. Springer, Heidelberg (2009)Cappiello, C., Daniel, F., Matera, M., Pautasso, C.: Information Quality in Mashups. IEEE Internet Computing 14(4), 32–40 (2010)Cappiello, C., Matera, M., Picozzi, M., Daniel, F., Fernandez, A.: Quality-Aware Mashup Composition: Issues, Techniques and Tools. In: 8th International Conference on the Quality of Information and Communications Technology (QUATIC 2012), pp. 10–19 (2012)Fenton, N.E., Pfleeger, S.L.: Software Metrics: A Rigorous and Practical Approach, 2nd edn. International Thompson 1996, pp. I–XII, 1–638 (1996) ISBN 978-1-85032-275-7Fernandez, A., Insfran, E., Abrahão, S.: Usability evaluation methods for the web: A systematic mapping study. Information and Software Technology 53(8), 789–817 (2011)Garousi, V., Mesbah, A., Betin-Can, A., Mirshokraie, S.: A systematic mapping study of web application testing. Information and Software Technology 55(8), 1374–1396 (2013)Grammel, L., Storey, M.-A.: A survey of mashup development environments. In: Chignell, M., Cordy, J., Ng, J., Yesha, Y. (eds.) The Smart Internet. LNCS, vol. 6400, pp. 137–151. Springer, Heidelberg (2010)Hoyer, V., Fischer, M.: Market Overview of Enterprise Mashup Tools. In: Bouguettaya, A., Krueger, I., Margaria, T. (eds.) ICSOC 2008. LNCS, vol. 5364, pp. 708–721. Springer, Heidelberg (2008)ISO/IEC: ISO/IEC 25010 Systems and software engineering. Systems and software Quality Requirements and Evaluation (SQuaRE). System and software quality models (2011)Kitchenham, B., Charters, S.: Guidelines for performing Systematic Literature Reviews in Software Engineering. Version 2.3, ESBE Technical Report, Keele University, UK (2007)Mendes, E.: A systematic review on the Web engineering research. In: International Symposium on Empirical Software Engineering (ISESE 2005), pp. 498–507 (2005)OrangeLabs: State of the Art in Mashup tools, SocEDA project, pp. 1–59 (2011)Petersen, K., Feldt, R., Mujtaba, S., Mattsson, M.: Systematic mapping studies in software engineering. In: 12th International Conference on Evaluation and Assessment in Software Engineering (EASE), pp. 68–77 (2008)Raza, M., Hussain, F.K., Chang, E.: A methodology for quality-based mashup of data sources. In: 10th International Conference on Information Integration and Web-based Applications & Services (iiWAS 2008), pp. 528–533 (2008)Saeed, A.: A Quality-based Framework for Leveraging the Process of Mashup Component Selection (2009), https://gupea.ub.gu.se/handle/2077/21953Sharma, A., Hellmann, T.D., Maurer, F.: Testing of Web Services - A Systematic Mapping. In: 8th World Congress on Services (SERVICES 2012), pp. 346–352 (2012
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