2,672 research outputs found
As Australian shipping grows, how can we avoid collisions with marine animals?
Living largely on the fringes of a giant island continent, Australians rely on sea transport for the exports and imports that sustain our economy and lifestyle. Australians also have a strong affinity with the ocean, as reflected in the growth in recreational boating and cruise shipping. But these numbers risk putting people on a collision course - literally - with whales, turtles and other marine life
Archaeological Site Examination, North Yard of the Loring-Greenough House, Jamaica Plain, Massachusetts
A phased program of stabilization and restoration for the Loring-Greenough House and property located in Jamaica Plain, a suburb of Boston, MA, called for reconstruction of porches, construction of an entrance walk and new foundations for the carriage house. This program also included landscaping and rehabilitation of garden plantings in the north yard. Archaeological testing was conducted to identify cultural resources that would be impacted by the proposed project and to search for evidence of early garden features that could be used to guide landscape restoration. The first phase of research focused on house porches, walkway installation and foundation work in the carriage house (Mohler and Kelley 2000). The second phase of work, reported herein, focused on the temporal assessment of existing planting beds and identification of historic planting features. A total of five 1 m x 1 m units and four 1 m x .5 m units were excavated in the north yard. Investigations revealed the presence of an intact buried A-horizon in the east and south portions of the north yard that contains eighteenth and early nineteenth century artifacts. Sand walkways were laid down in the early to mid nineteenth century and may have corresponded with other house improvements made around 1840. Such improvements may have included the creation of a formal garden with beds laid out in a geometric pattern. These garden features were covered over with landscaping fill sometime after 1937 when a plan of the property was made by the Historic American Buildings Survey. The present parallel garden beds may have been created simultaneously with the geometric garden. The parallel beds have been maintained with slight twentieth-century modification up to the present. The irregular lilac beds at the north edge of the property appear to date to the late nineteenth or early twentieth centuries, while the herb bed was created in the late twentieth century. Evidence of seventeenth to eighteenth century garden features consisting of a series of small planting holes was identified below the south end of the parallel beds and associated walkway. The program of archaeological testing revealed the presence of a well-preserved buried A-horizon across much of the property that is associated with the eighteenth and early nineteenth cenury occupation of the property. In addition evidence of eighteenth century gardening activity lies at the base of the buried A-horizon. An early nineteenth century pathway was found on the surface of the buried A-horizon. Due to the presence of well-preserved arcaeological deposits recommendations for proposed garden restoration focused on the need to limit the depth of new planting holes to prevent disturbance to the buried A-horizon. Because tree planting and erection of posts for arbors require greater depths, it was recommended that the new planting and post locations should be archaeologically excavated to mitigate potentially adverse impacts. The excavated holes will then be used for specific trees and posts. The third phase of archaeological investigation associated with the foundations of the carriage house north wall joists will be reported under separate cover
Report On the Archaeological Site Examination of the Entrance Drive, Carriage House, Greenhouse, Vegetable Garden, Flower Garden and Grapery at Gore Place, Waltham, Massachusetts
Alandscape restoration plan for the 45-acre Gore Place property in Waltham and Watertown, MA, calls for restoration of grounds, gardens and structures to depict and interpret the late eighteenth- and early nineteenth-century occupation of Massachusetts governor and United States senator, Christopher Gore, and his wife, Rebecca. The restoration plan includes archaeological investigation to help identify the location and integrity of six historically documented features on the Gore Place grounds. Blocks and transects of shovel test pits at 5, 10 and 20 meter intervals along with 1 x 1 m excavation units and trenching were employed in the archaeological site examination of these areas. Testing in the area of the present entrance drive revealed evidence of significant landscape alteration characterized by a unique process of top soil removal followed by filling first with a layer of stone, then loamy sand and gravel and finally replacement of topsoil, all in an effort to create flat and well-drained yard space. The existing entrance drive is hypothesized to have been constructed during the Gore occupation as was a separate service drive. Work at the site of the 1793 carriage house succeeded in pinpointing the location of the original foundation, a task that contributes to the structure’s relocation. The site of the Gore-period greenhouse was also identified by architectural remains that include fragments of marble tile flooring identical to that in the Gore Mansion. Astone-lined drain, glass bell jar fragments as well as a soapstone brick possibly associated with the greenhouse heating system were also found. Investigations in the vegetable and flower gardens revealed intact soils and late eighteenth- / early nineteenth-century artifacts suggesting Gore-period garden features may be preserved and are potentially archaeologically identifiable. Work in the area of the grapery/fruitwall revealed remains of the large greenhouse that occupied the site from the second quarter of the nineteenth century until ca. 1921. Intact greenhouse soils and foundations suggest that the original fruitwall footing is preserved within the later greenhouse foundation. All of these features are well preserved and exhibit a high level of integrity. Those areas of the property not tested during the survey may be archaeologically sensitive and may requrie testing in advance of future proposed impacts. Recommendations specific to each area include options for grounds restoration and interpretation as well as additional archaeological investigations to proceed in tandem with proposed landscape changes. The report also includes a summary of scholarly research associated with design landscape archaeology with reference to Massachusetts
Missing data in spatiotemporal datasets: the UK rainfall chemistry network
Rainfall chemistry networks inevitably report some missing data, caused by contamination or loss of samples. However, there are no universally accepted rules about how such data, particularly from samples contaminated in the field, are identified and reported, leading to uncertainties in data usage by third parties, and possible incorrect inferences based on the reported data. This paper describes how the UK rainfall chemistry network data have been analysed for contamination, and how missing values can be estimated based on cross-correlations in time and space, using data from 20 sites over 26 years. The final flagged dataset is available through the CEH Environmental Information Data Centre (EIDC). Erroneous data values are identified through consideration of ion balance (internal consistency), and evidence of contamination by birds or windblown dust based on the reported chemical analysis. Overall data capture with the erroneous data excluded and no replacement of missing data was 86%, but with much smaller data capture at some sites in some years, to less than 30% in some cases. The use of estimated data to replace missing values resulted in an increase in overall data capture to 96%, with only one site having data capture less than 70% in an individual year, and all sites achieving a data capture of 88% or more over the full period. The implications of using the reported ‘official’ annual data, as opposed to the dataset with missing values replaced by estimates, are illustrated by consideration of the temporal trend in nitrate at one site, which shows twice the value in the ‘official’ reported annual data compared with the ‘estimated’ data, part of a consistent pattern across all sites. Use of the uncorrected ‘raw’ sample data leads to large errors
Role of the Coulomb and the vector-isovector potentials in the isospin asymmetry of nuclear pseudospin
We investigate the role of the Coulomb and the vector-isovector
potentials in the asymmetry of the neutron and proton pseudospin splittings in
nuclei. To this end, we solve the Dirac equation for the nucleons using central
vector and scalar potentials with Woods-Saxon shape and and dependent
Coulomb and potentials added to the vector potential. We study the
effect of these potentials on the energy splittings of proton and neutron
pseudospin partners along a Sn isotopic chain. We use an energy decomposition
proposed in a previous work to assess the effect of a pseudospin-orbit
potential on those splittings. We conclude that the effect of the Coulomb
potential is quite small and the potential gives the main contribution
to the observed isospin asymmetry of the pseudospin splittings. This isospin
asymmetry results from a cancellation of the various energy terms and cannot be
attributed only to the pseudospin-orbit term, confirming the dynamical
character of this symmetry pointed out in previous works.Comment: 9 pages, 11 figures, uses revtex4; title was changed and several
small corrections were made throughout the tex
Quantitative assessment of relative ship strike risk to humpback whales (Megaptera novaeangliae) in the Great Barrier Reef World Heritage Area
The Australian east coast population of humpback whales (E1 sub-population) annually migrate to the Great Barrier Reef for mating and calving. Recent improvements in our understanding of the distribution of humpback whales on their breeding ground in the Great Barrier Reef World Heritage Area (GBRWHA) indicate the main breeding aggregation (highest density area) is in offshore waters of the southern GBR, in close proximity to coastal areas undergoing significant port development. The core breeding area overlaps the inner shipping route that services all ports on the Qld coast. A quantitative assessment of relative ship strike risk (ships > 80m) to humpback whales in the GBRWHA was recently undertaken. However, it was not possible to model the Capricorn Bunker Group due to limited humpback whale distribution data. This Capricorn Bunker Group is an area of significant shipping activity and represents a significant information gap on relative risk of ship strike to humpback whales in the GBR. This report presents data on the distribution of humpback whales in the Capricorn Bunker Group area from an aerial survey undertaken in July 2018. This data enabled a quantitative relative ship strike risk assessment for this area and a re-assessment of risk in the extended GBRWHA when integrated with existing aerial survey data
Avoiding the collision course
Attitudes about collisions between whales and vessels
have changed drastically since this account from a newspaper in 1891. Rather than sensational, we now view such incidents as tragic, and internationally, vessel strikes are recognized as a potential threat to whale populations.
Worldwide, the main species affected by vessel collisions are fin whales, followed by humpback, northern right, gray, minke, sperm, southern right and blue whales. During the last two centuries of whaling almost all of these species were brought to the brink of extinction
Pseudospin symmetry as a relativistic dynamical symmetry in the nucleus
Pseudospin symmetry in nuclei is investigated by solving the Dirac equation
with Woods-Saxon scalar and vector radial potentials, and studying the
correlation of the energy splittings of pseudospin partners with the nuclear
potential parameters. The pseudospin interaction is related to a
pseudospin-orbit term that arises in a Schroedinger-like equation for the lower
component of the Dirac spinor. We show that the contribution from this term to
the energy splittings of pseudospin partners is large. The near pseudospin
degeneracy results from a significant cancelation among the different terms in
that equation, manifesting the dynamical character of this symmetry in the
nucleus. We analyze the isospin dependence of the pseudospin symmetry and find
that its dynamical character is behind the different pseudospin splittings
observed in neutron and proton spectra of nuclei.Comment: 13 pages, 9 figures, uses REVTeX4 macro
- …