466 research outputs found
LIST OF THE PLEUROTOMIDĂ OF SOUTH AUSTRALIA, WITH DESCRIPTIONS OF SOME NEW SPECIES
Volume: 2 ; Start Page: 24 ; End Page: 3
Fast Neutron And Gamma-ray Detectors For The Csiro Air Cargo Scanner
oS(FNDA2006)074 © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence
Assessing the Impacts of Engaging with a Touch Table on Safari Park Visitors
Modern zoos are increasingly viewed as educational facilities, with informal education programmes attempting to engage with visitors through a wide variety of methods. A âtouch tableâ consists of two collapsible tables which display a variety of artefacts to the public. This study investigated visitor engagement with touch tables alongside types of conversations being initiated by visitors. Covert observations recorded the type of groups visiting, their dwell time, perceived engagement level and the types of interactions and conversations they were initiating at the touch table. Dwell time was affected by the season, member of staff present, type of group visiting the touch table and engagement level of the group. Engagement level was also affected by group type. Longer average dwell time and higher engagement levels were displayed at a long-established touch table location, whereas more visitors engaged at the touch table when it was at a new location with predicted high footfall. Here, 68.3% of visitors initiated âsurface levelâ conversation, 27.2% initiated âdeeper levelâ conversation and 89.6% initiated âotherâ conversation. This study resulted in touch table offerings being adapted to further increase their effectiveness as an informal education tool and to suggests ways in which touch tables can continue in a post COVID-19 world
Monte-Carlo Simulations of Radiation-Induced Activation in a Fast-Neutron and Gamma- Based Cargo Inspection System
An air cargo inspection system combining two nuclear reaction based
techniques, namely Fast-Neutron Resonance Radiography and Dual-Discrete-Energy
Gamma Radiography is currently being developed. This system is expected to
allow detection of standard and improvised explosives as well as special
nuclear materials. An important aspect for the applicability of nuclear
techniques in an airport inspection facility is the inventory and lifetimes of
radioactive isotopes produced by the neutron and gamma radiation inside the
cargo, as well as the dose delivered by these isotopes to people in contact
with the cargo during and following the interrogation procedure. Using MCNPX
and CINDER90 we have calculated the activation levels for several typical
inspection scenarios. One example is the activation of various metal samples
embedded in a cotton-filled container. To validate the simulation results, a
benchmark experiment was performed, in which metal samples were activated by
fast-neutrons in a water-filled glass jar. The induced activity was determined
by analyzing the gamma spectra. Based on the calculated radioactive inventory
in the container, the dose levels due to the induced gamma radiation were
calculated at several distances from the container and in relevant time windows
after the irradiation, in order to evaluate the radiation exposure of the cargo
handling staff, air crew and passengers during flight. The possibility of
remanent long-lived radioactive inventory after cargo is delivered to the
client is also of concern and was evaluated.Comment: Proceedings of FNDA 201
Freshwater umbrella - the effects of nitrogen deposition & climate change on freshwaters in the UK
In upland areas of the UK located away from direct human disturbance through agriculture,
industrial activities and urban pollution, atmospheric pollution poses one of the major threats
to the chemical and biological quality of lakes and streams. One of the most important groups
of pollutants is nitrogen (N) compounds, including oxidised forms of N called NOx, generated
mainly by fossil fuel combustion especially in motor vehicles, and reduced forms of N
(ammonia gas or dissolved ammonium compounds) generated mainly from agricultural
activities and livestock. These nitrogen compounds may dissolve in rain or soilwater to form
acids, or may be taken up as nutrients by plants and soil microbes in upland catchments, and
then subsequently released in acid form associated with nitrate leaching at a later date. It is
well established that nitrate leaching contributes to acidification of upland waters, with
damage to aquatic ecosystems including plants, invertebrates and fish. However it has
recently been suggested that nitrate leaching may also be associated with nutrient enrichment
of upland waters that contain biological communities adapted to very low nutrient levels
Synthesizing greenhouse gas fluxes across nine European peatlands and shrublands: responses to climatic and environmental changes
In this study, we compare annual fluxes of methane
(CH4), nitrous oxide (N2O) and soil respiratory carbon dioxide
(CO2) measured at nine European peatlands (n = 4) and
shrublands (n = 5). The sites range from northern Sweden
to Spain, covering a span in mean annual air temperature
from 0 to 16 ïżœC, and in annual precipitation from 300 to
1300mmyrâ1. The effects of climate change, including temperature
increase and prolonged drought, were tested at five
shrubland sites. At one peatland site, the long-term (>30 yr)
effect of drainage was assessed, while increased nitrogen deposition
was investigated at three peatland sites.
The shrublands were generally sinks for atmospheric CH4,
whereas the peatlands were CH4 sources, with fluxes ranging
from â519 to +6890 mgCH4-Cmâ2 yrâ1 across the studied
ecosystems. At the peatland sites, annual CH4 emission
increased with mean annual air temperature, while
a negative relationship was found between net CH4 uptake
and the soil carbon stock at the shrubland sites. Annual
N2O fluxes were generally small ranging from â14
to 42 mgN2O-Nmâ2 yrâ1. Highest N2O emission occurred
at the sites that had highest nitrate (NOâ
3 ) concentration
in the soil water. Furthermore, experimentally increased
NOâ
3 deposition led to increased N2O efflux, whereas prolonged
drought and long-term drainage reduced the N2O efflux.
Soil CO2 emissions in control plots ranged from 310
to 732 gCO2-Cmâ2 yrâ1. Drought and long-term drainage generally reduced the soil CO2 efflux, except at a hydric
shrubland where drought tended to increase soil respiration.
In terms of fractional importance of each greenhouse gas
to the total numerical global warming response, the change in
CO2 efflux dominated the response in all treatments (ranging
71â96 %), except for NOâ
3 addition where 89% was due to
change in CH4 emissions. Thus, in European peatlands and
shrublands the effect on global warming induced by the investigated
anthropogenic disturbances will be dominated by
variations in soil CO2 fluxes
Nitrous oxide emissions from European agriculture - An analysis of variability and drivers of emissions from field experiments
Nitrous oxide emissions from a network of agricultural experiments in Europe were used to explore the relative importance of site and management controls of emissions. At each site, a selection of management interventions were compared within replicated experimental designs in plot-based experiments. Arable experiments were conducted at Beano in Italy, El Encin in Spain, Foulum in Denmark, LogĂ„rden in Sweden, Maulde in Belgium, Paulinenaue in Germany, and Tulloch in the UK. Grassland experiments were conducted at Crichton, Nafferton and Peaknaze in the UK, Gödöllö in Hungary, Rzecin in Poland, Zarnekow in Germany and Theix in France. Nitrous oxide emissions were measured at each site over a period of at least two years using static chambers. Emissions varied widely between sites and as a result of manipulation treatments. Average site emissions (throughout the study period) varied between 0.04 and 21.21 kg N<sub>2</sub>O-N ha<sup>â1</sup> yr<sup>â1</sup>, with the largest fluxes and variability associated with the grassland sites. Total nitrogen addition was found to be the single most important determinant of emissions, accounting for 15% of the variance (using linear regression) in the data from the arable sites (<i>p</i> < 0.0001), and 77% in the grassland sites. The annual emissions from arable sites were significantly greater than those that would be predicted by IPCC default emission factors. Variability of N<sub>2</sub>O emissions within sites that occurred as a result of manipulation treatments was greater than that resulting from site-to-site and year-to-year variation, highlighting the importance of management interventions in contributing to greenhouse gas mitigation
Ammonite stratigraphy of a Toarcian (Lower Jurassic) section on Nagy-Pisznice Hill (Gerecse Mts, Hungary)
Abstract
In the Jurassic rocks exposed in a small abandoned quarry on the northwestern edge of Nagy-Pisznice Hill in the Gerecse Mts, fairly well preserved parts of a crocodile skeleton was found in 1996. The bed which yielded the skeletal remains is the uppermost layer of the Kisgerecse Marl Formation exposed here and was determined as belonging to the Upper Toarcian Grammoceras thouarsense Zone. The beds of the sequence above and below were carefully sampled in the late 1990s, and the encountered ammonites were evaluated biostratigraphically. As a result, the Lower Toarcian Harpoceras serpentinum Zone, the Middle Toarcian Hildoceras bifrons and Merlaites gradatus Zones, and the Upper Toarcian Grammoceras thouarsense and Geczyceras speciosum Zones were identified. Within most of these zones the subzones and even the faunal horizons were successfully recognized. The lowermost beds above the underlying Pliensbachian red limestone did not yield any fossils; thus the lowermost Toarcian Dactylioceras tenuicostatum Zone could not be documented. The highest Toarcian ammonite zones also remained unidentified, because the beds of the Tölgyhåt Limestone above were not sampled all the way up. This paper presents the lithostratigraphic and biostratigraphic details of the sequence, and the paleontological descriptions of the most important ammonites
The genus Plesiophysa, with a redescription of P. ornata (Haas, 1938) (Gastropoda: Planorbidae)
A review of the ecology, palaeontology and distribution of atlantid heteropods (Caenogastropoda: Pterotracheoidea: Atlantidae)
Fewer than 1% of marine gastropod species live a holoplanktic life. Of these, the shelled heteropods of the family Atlantidae are among the most poorly understood. The atlantids potentially make up an important part of the ocean zooplankton, composing up to 69% of shelled holoplanktic gastropods in the Late Pleistocene to Recent fossil record. They are also likely to be at high risk from current and future global changes, including anthropogenic ocean acidification. However, due to their small size (<12 mm), difficulty of sampling and complicated morphology, we still lack key information about atlantid taxonomy and ecology. This makes it difficult to understand how important they are in the ocean foodweb and how they will be affected by environmental change. Although many studies have been carried out on the atlantids, these have generally been broad and unconnected. Here, we draw together this previous research, summarizing what is currently known about atlantid taxonomy, palaeontology, ecology and biogeography, and aiming to provide a foundation for future research on this group. The data indicate complex behaviours involving seasonal and vertical migration, and demonstrate extended geographical ranges, with implications for understanding the role of atlantids in the ocean foodweb and their sensitivity to environmental changes. This review highlights the urgent need for further taxonomic research on the atlantids, including molecular analysis, and for improved sampling techniques
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