40 research outputs found
Technoscience and the modernization of freshwater fisheries assessment and management
Inland fisheries assessment and management are challenging given the inherent com-
plexity of working in diverse habitats (e.g., rivers, lakes, wetlands) that are dynamic
on organisms that are often cryptic and where fishers are often highly mobile. Yet,
technoscience is offering new tools that have the potential to reimagine how inland
fisheries are assessed and managed. So-called ‘‘technoscience’’ refers to instances in
which science and technology unfurl together, offering novel ways of spurring and
achieving meaningful change. This paper considers the role of technoscience and its
potential for modernizing the assessment and management of inland fisheries. It first
explores technoscience and its potential benefits, followed by presentation of a series
of synopses that explore the application (both successes and challenges) of new tech-
nologies such as environmental DNA (eDNA), genomics, electronic tags, drones, phone
apps, iEcology, and artificial intelligence to assessment and management. The paper
also considers the challenges and barriers that exist in adopting new technologies. The
paper concludes with a provocative assessment of the potential of technoscience to
reform and modernize inland fisheries assessment and management. Although these
tools are increasingly being embraced, there is a lack of platforms for aggregating these
data streams and providing managers with actionable information in a timely manner.
The ideas presented here should serve as a catalyst for beginning to work collectively
and collaboratively towards fisheries assessment and management systems that harness
the power of technology and serve to modernize inland fisheries management. Such
transformation is urgently needed given the dynamic nature of environmental change,
the evolving threat matrix facing inland waters, and the complex behavior of fishers.
Quite simply, a dynamic world demands dynamic fisheries management; technoscience
has made that within reach.publishedVersio
Low-mass pre--main-sequence stars in the Magellanic Clouds
[Abridged] The stellar Initial Mass Function (IMF) suggests that sub-solar
stars form in very large numbers. Most attractive places for catching low-mass
star formation in the act are young stellar clusters and associations, still
(half-)embedded in star-forming regions. The low-mass stars in such regions are
still in their pre--main-sequence (PMS) evolutionary phase. The peculiar nature
of these objects and the contamination of their samples by the evolved
populations of the Galactic disk impose demanding observational techniques for
the detection of complete numbers of PMS stars in the Milky Way. The Magellanic
Clouds, the companion galaxies to our own, demonstrate an exceptional star
formation activity. The low extinction and stellar field contamination in
star-forming regions of these galaxies imply a more efficient detection of
low-mass PMS stars than in the Milky Way, but their distance from us make the
application of special detection techniques unfeasible. Nonetheless, imaging
with the Hubble Space Telescope yield the discovery of solar and sub-solar PMS
stars in the Magellanic Clouds from photometry alone. Unprecedented numbers of
such objects are identified as the low-mass stellar content of their
star-forming regions, changing completely our picture of young stellar systems
outside the Milky Way, and extending the extragalactic stellar IMF below the
persisting threshold of a few solar masses. This review presents the recent
developments in the investigation of PMS stars in the Magellanic Clouds, with
special focus on the limitations by single-epoch photometry that can only be
circumvented by the detailed study of the observable behavior of these stars in
the color-magnitude diagram. The achieved characterization of the low-mass PMS
stars in the Magellanic Clouds allowed thus a more comprehensive understanding
of the star formation process in our neighboring galaxies.Comment: Review paper, 26 pages (in LaTeX style for Springer journals), 4
figures. Accepted for publication in Space Science Review
The current state of the use of large wood in river restoration and management
Trees fall naturally into rivers generating flow heterogeneity, inducing geomorphological features, and creating habitats for biota. Wood is increasingly used in restoration projects and the potential of wood acting as leaky barriers to deliver natural flood management by “slowing the flow” is recognised. However, wood in rivers can pose a risk to infrastructure and locally increase flood hazards. The aim of this paper is to provide an up-to-date summary of the benefits and risks associated with using wood to promote geomorphological processes to restore and manage rivers. This summary was developed through a workshop that brought together academics, river managers, restoration practitioners and consultants in the UK to share science and best-practice on wood in rivers. A consensus was developed on four key issues: (i) hydro-geomorphological effects, (ii) current use in restoration and management, (iii) uncertainties and risks, and (iv) tools and guidance required to inform process-based restoration and management
State of the climate in 2013
In 2013, the vast majority of the monitored climate variables reported here maintained trends established in recent decades. ENSO was in a neutral state during the entire year, remaining mostly on the cool side of neutral with modest impacts on regional weather patterns around the world. This follows several years dominated by the effects of either La Niña or El Niño events. According to several independent analyses, 2013 was again among the 10 warmest years on record at the global scale, both at the Earths surface and through the troposphere. Some regions in the Southern Hemisphere had record or near-record high temperatures for the year. Australia observed its hottest year on record, while Argentina and New Zealand reported their second and third hottest years, respectively. In Antarctica, Amundsen-Scott South Pole Station reported its highest annual temperature since records began in 1957. At the opposite pole, the Arctic observed its seventh warmest year since records began in the early 20th century. At 20-m depth, record high temperatures were measured at some permafrost stations on the North Slope of Alaska and in the Brooks Range. In the Northern Hemisphere extratropics, anomalous meridional atmospheric circulation occurred throughout much of the year, leading to marked regional extremes of both temperature and precipitation. Cold temperature anomalies during winter across Eurasia were followed by warm spring temperature anomalies, which were linked to a new record low Eurasian snow cover extent in May. Minimum sea ice extent in the Arctic was the sixth lowest since satellite observations began in 1979. Including 2013, all seven lowest extents on record have occurred in the past seven years. Antarctica, on the other hand, had above-average sea ice extent throughout 2013, with 116 days of new daily high extent records, including a new daily maximum sea ice area of 19.57 million km2 reached on 1 October. ENSO-neutral conditions in the eastern central Pacific Ocean and a negative Pacific decadal oscillation pattern in the North Pacific had the largest impacts on the global sea surface temperature in 2013. The North Pacific reached a historic high temperature in 2013 and on balance the globally-averaged sea surface temperature was among the 10 highest on record. Overall, the salt content in nearsurface ocean waters increased while in intermediate waters it decreased. Global mean sea level continued to rise during 2013, on pace with a trend of 3.2 mm yr-1 over the past two decades. A portion of this trend (0.5 mm yr-1) has been attributed to natural variability associated with the Pacific decadal oscillation as well as to ongoing contributions from the melting of glaciers and ice sheets and ocean warming. Global tropical cyclone frequency during 2013 was slightly above average with a total of 94 storms, although the North Atlantic Basin had its quietest hurricane season since 1994. In the Western North Pacific Basin, Super Typhoon Haiyan, the deadliest tropical cyclone of 2013, had 1-minute sustained winds estimated to be 170 kt (87.5 m s-1) on 7 November, the highest wind speed ever assigned to a tropical cyclone. High storm surge was also associated with Haiyan as it made landfall over the central Philippines, an area where sea level is currently at historic highs, increasing by 200 mm since 1970. In the atmosphere, carbon dioxide, methane, and nitrous oxide all continued to increase in 2013. As in previous years, each of these major greenhouse gases once again reached historic high concentrations. In the Arctic, carbon dioxide and methane increased at the same rate as the global increase. These increases are likely due to export from lower latitudes rather than a consequence of increases in Arctic sources, such as thawing permafrost. At Mauna Loa, Hawaii, for the first time since measurements began in 1958, the daily average mixing ratio of carbon dioxide exceeded 400 ppm on 9 May. The state of these variables, along with dozens of others, and the 2013 climate conditions of regions around the world are discussed in further detail in this 24th edition of the State of the Climate series. © 2014, American Meteorological Society. All rights reserved
A MODEST review
We present an account of the state of the art in the fields explored by the
research community invested in 'Modeling and Observing DEnse STellar systems'.
For this purpose, we take as a basis the activities of the MODEST-17
conference, which was held at Charles University, Prague, in September 2017.
Reviewed topics include recent advances in fundamental stellar dynamics,
numerical methods for the solution of the gravitational N-body problem,
formation and evolution of young and old star clusters and galactic nuclei,
their elusive stellar populations, planetary systems, and exotic compact
objects, with timely attention to black holes of different classes of mass and
their role as sources of gravitational waves.
Such a breadth of topics reflects the growing role played by collisional
stellar dynamics in numerous areas of modern astrophysics. Indeed, in the next
decade, many revolutionary instruments will enable the derivation of positions
and velocities of individual stars in the Milky Way and its satellites and will
detect signals from a range of astrophysical sources in different portions of
the electromagnetic and gravitational spectrum, with an unprecedented
sensitivity. On the one hand, this wealth of data will allow us to address a
number of long-standing open questions in star cluster studies; on the other
hand, many unexpected properties of these systems will come to light,
stimulating further progress of our understanding of their formation and
evolution.Comment: 42 pages; accepted for publication in 'Computational Astrophysics and
Cosmology'. We are much grateful to the organisers of the MODEST-17
conference (Charles University, Prague, September 2017). We acknowledge the
input provided by all MODEST-17 participants, and, more generally, by the
members of the MODEST communit
The Kinematics of Active Late Type Stars Observed by the ROSAT Wide-Field Camera
A sample of single, main-sequence late-type stars detected during the ROSAT Wide Field Camera EUV all-sky survey is kinematically investigated. It is confirmed that the galactic velocity dispersion of magnetically active objects, as defined by the ratio of EUV to bolometric flux, is substantially less than that of a random sample of late-type stars. This is due to the relationships between rotation and magnetic activity, age and rotation, and velocity dispersion and age. It is found, however, that the choice of only the most active stars does not decrease the velocity dispersions any further, and this may be evidence either for a long spin-down time-scale for the dMe stars that constitute the majority of this sample, or that very young stars are clumped around discrete velocity vectors that are somewhat separated in velocity space. A cluster analysis of the data reveals strong evidence for groups in the kinematic data that have space motions coincident with the Local Association and Sirius supercluster streams. These stellar streams are associated with the Pleiades and Ursa Major open clusters, with ages of
The effect of calcium on activation and induction of the pectolytic enzymes produced by Colletotrichum gloeosporioides
The effect of different substrates on the production of pectolytic enzymes by Colletotrichum gloeosporioides was studied. Cell walls of tomato induced the highest amounts of both polygalacturonase (PG) and pectate lyase (PL). Calcium activated and induced higher amounts of PL but had no effect on the activation and induction of PG. The role of calcium in controlling soft rot diseases and the lack of potential for using calcium in control of anthracnose of mango is discussed
Stable isotope mixing models elucidate sex and size effects on the diet of a generalist marine predator
We applied a 2-step clustering algorithm and Bayesian stable isotope mixing model
to examine intraspecific differences in the contribution of prey sources to the diet and foraging habitat of harbor seals Phoca vitulina in the Salish Sea, USA. We analyzed stable isotopes of carbon and nitrogen collected from 32 seals and 248 prey samples representing 18 of 25 of the most common seal prey items identified in seal scat. Stable isotope analyses identified significant harbor
seal sex- and size-based differences in diet and foraging habitat use. In comparison to males, female harbor seals had a higher contribution of prey items that were more 13C-enriched. This result may indicate that females derived more of their δ13C value from nearshore versus offshore food webs, an explanation supported by movement data on this population. However, large seals of both sexes displayed a greater offshore signal in their diet, indicating that seal mass effects on
foraging habitat use were somewhat independent of sex. Our work contributes to understanding
trophic linkages between these generalist consumers and their prey. The foraging differences that we detected between male and female harbor seals present complex challenges for fisheries management and for the design of marine reserves. Many marine reserves in the Pacific Northwest are located in close proximity to seal haul-out sites. By lowering the energetic costs of foraging of females, these reserves may ultimately have the unintended effect of increasing individual fitness, population growth rate, and influencing future predator-induced mortality on endangered species