Vertebrate fauna and fire regimes: a conceptual model to aid fire research and management

2012 ◽  
Vol 124 (1) ◽  
pp. 20 ◽  
Author(s):  
Richard H. Loyn
Keyword(s):  
Conceptual Model ◽  
Population Level ◽  
Fire Regimes ◽  
Ex Situ ◽  
Vertebrate Fauna ◽  
Spatial And Temporal Scales ◽  
Before And After ◽  
Long Time ◽  
Time Frames

Vertebrate fauna respond actively to individual fires by movement before and after the event, as well as by mortality and reproduction at the population level. They rely very much on mechanisms for avoiding fire fronts and ex situ recolonisation of burnt and regenerating habitat, as well as in situ survival. This sets them apart from most plant species and the more sedentary examples of invertebrate fauna. Rates of recolonisation after fire events depend on habitat development, and this includes both structure and floristic aspects of the vegetation, and also on accessibility of refuge habitat. Strategies for conserving vertebrate fauna need to take a broad landscape perspective to ensure that fire regimes are designed so that species can survive particular fire events in the broad landscape, and have potential to recolonise habitat as it becomes suitable over time. Long-unburnt vegetation provides important habitat for some species and should be valued accordingly. Long time-frames may be needed for some structural elements to develop after severe fires. Hence it is necessary to think big in managing habitat for vertebrate fauna, at both spatial and temporal scales. A conceptual model is offered for doing this, and a research program is described which aims to provide the detail necessary to make appropriate settings in policy and management frameworks.

scholarly journals Application of the MSAP Technique to Evaluate Epigenetic Changes in Plant Conservation

2020 ◽  
Vol 21 (20) ◽  
pp. 7459
Author(s):  
María Elena González-Benito ◽  
Miguel Ángel Ibáñez ◽  
Michela Pirredda ◽  
Sara Mira ◽  
Carmen Martín
Keyword(s):  
Dna Methylation ◽  
In Situ Conservation ◽  
Plant Conservation ◽  
Ex Situ ◽  
Conservation Strategies ◽  
Regenerated Plants ◽  
Before And After ◽  
Methylation Patterns

Epigenetic variation, and particularly DNA methylation, is involved in plasticity and responses to changes in the environment. Conservation biology studies have focused on the measurement of this variation to establish demographic parameters, diversity levels and population structure to design the appropriate conservation strategies. However, in ex situ conservation approaches, the main objective is to guarantee the characteristics of the conserved material (phenotype and epi-genetic). We review the use of the Methylation Sensitive Amplified Polymorphism (MSAP) technique to detect changes in the DNA methylation patterns of plant material conserved by the main ex situ plant conservation methods: seed banks, in vitro slow growth and cryopreservation. Comparison of DNA methylation patterns before and after conservation is a useful tool to check the fidelity of the regenerated plants, and, at the same time, may be related with other genetic variations that might appear during the conservation process (i.e., somaclonal variation). Analyses of MSAP profiles can be useful in the management of ex situ plant conservation but differs in the approach used in the in situ conservation. Likewise, an easy-to-use methodology is necessary for a rapid interpretation of data, in order to be readily implemented by conservation managers.

scholarly journals Sentinel-1 SAR Amplitude Imagery for Rapid Landslide Detection

2019 ◽  
Vol 11 (7) ◽  
pp. 760 ◽  
Author(s):  
Alessandro Mondini ◽  
Michele Santangelo ◽  
Margherita Rocchetti ◽  
Enrica Rossetto ◽  
Andrea Manconi ◽  
...  
Keyword(s):  
Forecast Model ◽  
Spatial And Temporal Scales ◽  
Systematic Assessment ◽  
Triggering Factors ◽  
Optical Images ◽  
Before And After ◽  
Long Time ◽  
Model Tuning ◽  
Magnitude Assessment ◽  
Event Magnitude

Despite landslides impact the society worldwide every day, landslide information is inhomogeneous and lacking. When landslides occur in remote areas or where the availability of optical images is rare due to cloud persistence, they might remain unknown, or unnoticed for long time, preventing studies and hampering civil protection operations. The unprecedented availability of SAR C-band images provided by the Sentinel-1 constellation offers the opportunity to propose new solutions to detect landslides events. In this work, we perform a systematic assessment of Sentinel-1 SAR C-band images acquired before and after known events. We present the results of a pilot study on 32 worldwide cases of rapid landslides entailing different types, sizes, slope expositions, as well as pre-existing land cover, triggering factors and climatic regimes. Results show that in about eighty-four percent of the cases, changes caused by landslides on SAR amplitudes are unambiguous, whereas only in about thirteen percent of the cases there is no evidence. On the other hand, the signal does not allow for a systematic use to produce inventories because only in 8 cases, a delineation of the landslide borders (i.e., mapping) can be manually attempted. In a few cases, cascade multi-hazard (e.g., floods caused by landslides) and evidences of extreme triggering factors (e.g., strong earthquakes or very rapid snow melting) were detected. The method promises to increase the availability of information on landslides at different spatial and temporal scales with benefits for event magnitude assessment during weather-related emergencies, model tuning, and landslide forecast model validation, in particular when accurate mapping is not required.

In-Situ Observation Of Aln Formation During Nitridation Of Sapphire By Ultrahigh Vacuum Transmission Electron Microscopy

1997 ◽  
Vol 482 ◽  
Author(s):  
M. Yeadon ◽  
M. T. Marshall ◽  
F. Hamdani ◽  
S. Pekin ◽  
H. Morkoc ◽  
...  
Keyword(s):  
Ultrahigh Vacuum ◽  
Ex Situ ◽  
In Situ Observation ◽  
Island Growth ◽  
Kinetic Measurements ◽  
Transmission Electron ◽  
Before And After ◽  
Subsequent Exposure ◽  
Diffraction Patterns

AbstractUsing a novel ultrahigh vacuum transmission electron microscope (UHV TEM) with insitu molecular beam epitaxy capability we have studied the nitridation of (0001) sapphire upon exposure to ammonia. Atomically flat sapphire surfaces for the experiments were obtained by high temperature annealing. Subsequent exposure to ammonia flow at 950°C led to the successful synthesis of epitaxial AIN; the films were characterized in-situ using TEM. Complimentary ex-situ atomic force microscopy (AFM) was also performed in order to characterize the surface morphology before and after nitridation.The experiments indicate that AIN grows by a 3D island growth mechanism. Electron diffraction patterns suggest an abrupt AIN/sapphire interface with no evidence of the formation of Al–O–N compounds. The rate limiting step in the nitridation reaction appears to be the diffusion of nitrogen and oxygen species between the free surface of the growing AIN film and the reaction interface. It is inferred from kinetic measurements that diffusion of these species occurs along the boundaries between coalescing AIN islands.

scholarly journals Long time frames to detect the impact of changing COVID-19 measures, Canada, March to July 2020

2021 ◽  
Vol 26 (40) ◽  
Author(s):  
Jessica E Stockdale ◽  
Renny Doig ◽  
Joosung Min ◽  
Nicola Mulberry ◽  
Liangliang Wang ◽  
...  
Keyword(s):  
Population Level ◽  
Time Frame ◽  
Control Measures ◽  
Type Model ◽  
Time Period ◽  
Long Time ◽  
The Mean ◽  
Reported Data ◽  
Time Frames ◽  
The Impact

Background Many countries have implemented population-wide interventions to control COVID-19, with varying extent and success. Many jurisdictions have moved to relax measures, while others have intensified efforts to reduce transmission. Aim We aimed to determine the time frame between a population-level change in COVID-19 measures and its impact on the number of cases. Methods We examined how long it takes for there to be a substantial difference between the number of cases that occur following a change in COVID-19 physical distancing measures and those that would have occurred at baseline. We then examined how long it takes to observe this difference, given delays and noise in reported cases. We used a susceptible-exposed-infectious-removed (SEIR)-type model and publicly available data from British Columbia, Canada, collected between March and July 2020. Results It takes 10 days or more before we expect a substantial difference in the number of cases following a change in COVID-19 control measures, but 20–26 days to detect the impact of the change in reported data. The time frames are longer for smaller changes in control measures and are impacted by testing and reporting processes, with delays reaching ≥ 30 days. Conclusion The time until a change in control measures has an observed impact is longer than the mean incubation period of COVID-19 and the commonly used 14-day time period. Policymakers and practitioners should consider this when assessing the impact of policy changes. Rapid, consistent and real-time COVID-19 surveillance is important to minimise these time frames.

scholarly journals <i>In situ</i> observations of turbulent ship wakes and their potential implications for vertical mixing

2020 ◽  
Author(s):  
Amanda T. Nylund ◽  
Lars Arneborg ◽  
Anders Tengberg ◽  
Ulf Mallast ◽  
Ida-Maja Hassellöv
Keyword(s):  
Spatial Scales ◽  
Vertical Mixing ◽  
Turbulent Wake ◽  
Ex Situ ◽  
Landsat 8 ◽  
Spatial And Temporal Scales ◽  
Ship Traffic ◽  
Temporal And Spatial ◽  
Thermal Wake

Abstract. In areas of intensive ship traffic, ships pass every ten minutes. Considering the amount of ship traffic and the fact that global maritime trade is predicted to increase, there is a need to consider all effects shipping has on the marine environment; both pollution and physical disturbances. This paper studies a previously disregarded physical disturbance, namely ship-induced vertical mixing in the turbulent wake. A characterization of the temporal and spatial scales of the turbulent wake is needed to estimate its effect on gas exchange, dispersion of pollutants, and to identify in which areas ship-induced vertical mixing could have an impact on local biogeochemical cycles. There is a lack of field measurements of turbulent wakes of real-size ships, and this study addresses that gap by in situ and ex situ measurements of the depth, width, length, intensity and longevity of the turbulent wake for ~240 ship passages of differently sized ships. A bottom-mounted Acoustic Doppler Current Profiler (ADCP) was placed at 32 m depth below the ship lane outside Gothenburg harbour, and used to measure wake depth and temporal longevity. Thermal satellite images of the Thermal Infrared Sensor (TIRS) onboard Landsat 8 were used to measure thermal wake width and spatial longevity, using satellite scenes from the major ship lane North of Bornholm, Baltic Sea. Automatic Information System (AIS) records from both the investigated areas were used to identify the ships inducing the wakes. The results from the ADCP measurements show median wake depths of ~ 10 m, and several occasions of wakes reaching depths > 18 m. The temporal longevity of the wakes had a median of around 8 min and several passages of > 20 min. The satellite analysis showed a median thermal wake length of 13.7 km, and the longest wake extended over 60 km, which would correspond to a temporal longevity of 1 h 42 min (for a ship speed of 20 knots). The median thermal wake width was 157.5 m. The measurements of the spatial and temporal scales are in line with previous studies, but the deep mixing and extensive longevity presented in this study, has not previously been documented. The results from this study have shown that ship-induced vertical mixing occurs at temporal and spatial scales large enough to imply that this process should be considered when estimating environmental impact from shipping in areas with intense ship traffic. Moreover, the possibility that deep vertical mixing could occur in a highly frequent manner highlights the need of further studies to better characterize the spatial and temporal development of the turbulent wake.

scholarly journals Long time frames to detect the impact of changing COVID-19 control measures

2020 ◽  
Author(s):  
Jessica E Stockdale ◽  
Renny Doig ◽  
Joosung Min ◽  
Nicola Mulberry ◽  
Liangliang Wang ◽  
...  
Keyword(s):  
Population Level ◽  
Time Frame ◽  
Control Measures ◽  
Policy Makers ◽  
Time Period ◽  
Reporting Process ◽  
Long Time ◽  
The Mean ◽  
Time Frames ◽  
The Impact

AbstractBackgroundMany countries have implemented population-wide interventions such as physical distancing measures, in efforts to control COVID-19. The extent and success of such measures has varied. Many jurisdictions with declines in reported COVID-19 cases are moving to relax measures, while others are continuing to intensify efforts to reduce transmission.AimWe aim to determine the time frame between a change in COVID-19 measures at the population level and the observable impact of such a change on cases.MethodsWe examine how long it takes for there to be a substantial difference between the cases that occur following a change in control measures and those that would have occurred at baseline. We then examine how long it takes to detect a difference, given delays and noise in reported cases. We use changes in population-level (e.g., distancing) control measures informed by data and estimates from British Columbia, Canada.ResultsWe find that the time frames are long: it takes three weeks or more before we might expect a substantial difference in cases given a change in population-level COVID-19 control, and it takes slightly longer to detect the impacts of the change. The time frames are shorter (11-15 days) for dramatic changes in control, and they are impacted by noise and delays in the testing and reporting process, with delays reaching up to 25-40 days.ConclusionThe time until a change in broad control measures has an observed impact is longer than is typically understood, and is longer than the mean incubation period (time between exposure than onset) and the often used 14 day time period. Policy makers and public health planners should consider this when assessing the impact of policy change, and efforts should be made to develop rapid, consistent real-time COVID-19 surveillance.

Rheological Measurement of In Situ Preheating Polycarbosilane Melt

2017 ◽  
Vol 726 ◽  
pp. 90-94 ◽  
Author(s):  
Liu Ying Huang ◽  
Zi Qing Zhu ◽  
Xuan Cheng ◽  
Ying Zhang
Keyword(s):  
Ex Situ ◽  
Heating Process ◽  
Rheological Measurement ◽  
Rheological Measurements ◽  
Molecular Weight Distributions ◽  
Weight Distributions ◽  
Before And After ◽  
Expansion System ◽  
Properties Of Materials

Rotational rheometer has been widely used in studying rheological properties of materials. However, the conventional rheological measurements may not be applicable for some non-traditional materials with characteristic properties. Polycarbosilane (PCS) is an oligomer and in the form of solid state at room temperature. A large amount of air bubbles are evolved during the heating process of PCS, which is extremely harmful for rheological measurements of PCS melt and detrimentally influences the accuracy of rheological data. In this work, a series of PCS raw samples were pretreated with different heating processes by the advanced rheometric expansion system at 315°C before the rheological measurements at 295°C. The softening point temperatures and molecular weight distributions of different PCS samples were obtained before and after the preheating processes. The experimental data collected with the in-situ preheating and ex-situ preheating for 1 h were compared.

scholarly journals Hybrid Geopolymeric Foams for the Removal of Metallic Ions from Aqueous Waste Solutions

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4091 ◽  
Author(s):  
Giuseppina Roviello ◽  
Elena Chianese ◽  
Claudio Ferone ◽  
Laura Ricciotti ◽  
Valentina Roviello ◽  
...  
Keyword(s):  
Metal Ions ◽  
Metallic Ions ◽  
Ultrapure Water ◽  
Experimental Procedure ◽  
Strength Tests ◽  
Before And After ◽  
Long Time ◽  
Alkaline Conditions ◽  
First Time

For the first time, hybrid organic–inorganic geopolymeric foams were successfully used as monolithic adsorbents for the removal of metallic ions pollutants from wastewaters. The foams were realized by the in situ foaming of a hybrid geopolymer obtained by a reaction of metakaolin and polysiloxane oligomers under strong alkaline conditions and then cured at room temperature. In this way, porous materials with densities ranging from 0.4 to 0.7 g/cm3 and showing good mechanical properties were produced. With the aim of producing self-standing monolithic adsorbents for the removal of metallic ions pollutants from wastewaters, these porous hybrid geopolymers were subjected to a washing pretreatment with ultrapure water, dried, and then used for absorption tests by dipping them into an aqueous solution with an initial concentration of 20 ppm of Pb2+, Cd2+, Cu2+, and Zn2+ ions. Preliminary results indicated that all the tested materials are effective in the adsorption of the tested metal ions and do not release the removed metal ions upon sinking in ultrapure water, even for a very long time. Interestingly, compressive strength tests performed before and after the washing treatments show that the foamed samples remain intact and maintain their physical–mechanical characteristics, suggesting that these kinds of materials are promising candidates for the production of self-standing, monolithic adsorbent substrates that can be easily collected when exhausted, which is a major advantage in comparison with the use of powdered adsorbents. Moreover, since these materials can be obtained by a simple and versatile experimental procedure, they could be easily shaped or directly foamed into precast molds to be used in packed beds as membranes.

scholarly journals In Situ Ptychography of Heterogeneous Catalysts using Hard X-Rays: High Resolution Imaging at Ambient Pressure and Elevated Temperature

2016 ◽  
Vol 22 (1) ◽  
pp. 178-188 ◽  
Author(s):  
Sina Baier ◽  
Christian D. Damsgaard ◽  
Maria Scholz ◽  
Federico Benzi ◽  
Amélie Rochet ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Elevated Temperature ◽  
Gas Flow ◽  
Heterogeneous Catalysts ◽  
Ambient Pressure ◽  
Ex Situ ◽  
X Rays ◽  
X Ray ◽  
Before And After

AbstractA new closed cell is presented for in situ X-ray ptychography which allows studies under gas flow and at elevated temperature. In order to gain complementary information by transmission and scanning electron microscopy, the cell makes use of a Protochips E-chipTM which contains a small, thin electron transparent window and allows heating. Two gold-based systems, 50 nm gold particles and nanoporous gold as a relevant catalyst sample, were used for studying the feasibility of the cell. Measurements showing a resolution around 40 nm have been achieved under a flow of synthetic air and during heating up to temperatures of 933 K. An elevated temperature exhibited little influence on image quality and resolution. With this study, the potential of in situ hard X-ray ptychography for investigating annealing processes of real catalyst samples is demonstrated. Furthermore, the possibility to use the same sample holder for ex situ electron microscopy before and after the in situ study underlines the unique possibilities available with this combination of electron microscopy and X-ray microscopy on the same sample.

scholarly journals Influence of Morphological Changes in a Source Material on the Growth Interface of 4H-SiC Single Crystals

Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2591 ◽  
Author(s):  
Matthias Arzig ◽  
Johannes Steiner ◽  
Michael Salamon ◽  
Norman Uhlmann ◽  
Peter J. Wellmann
Keyword(s):  
Thermal Conductivity ◽  
Morphological Changes ◽  
Laser Flash ◽  
Source Material ◽  
Ex Situ ◽  
Growth Interface ◽  
Bulk Growth ◽  
Before And After ◽  
Conductivity Models

In this study, the change of mass distribution in a source material is tracked using an in situ computer tomography (CT) setup during the bulk growth of 4H- silicon carbide (SiC) via physical vapor depostion (PVT). The changing properties of the source material due to recrystallization and densification are evaluated. Laser flash measurement showed that the thermal properties of different regions of the source material change significantly before and after the growth run. The Si-depleted area at the bottom of the crucible is thermally insulating, while the residual SiC source showed increased thermal conductivity compared to the initially charged powder. Ex situ CT measurements revealed a needle-like structure with elongated pores causing anisotropic behavior for the heat conductivity. Models to assess the thermal conductivity are applied in order to calculate the changes in the temperature field in the crucible and the changes in growth kinetics are discussed.

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