Catastrophic Process Research Articles

ANATOMY OF A BOTTLENECK: DIAGNOSING FACTORS LIMITING POPULATION GROWTH IN THE PUERTO RICAN PARROT

The relative importance of genetic, demographic, environmental, and catastrophic processes that maintain population bottlenecks has received little consideration. We evaluate the role of these factors in maintaining the Puerto Rican Parrot (Amazona vittata) in a prolonged bottleneck from 1973 through 2000 despite intensive conservation efforts. We first conduct a risk analysis, then examine evidence for the importance of specific processes maintaining the bottleneck using the multiple competing hypotheses approach, and finally integrate these results through a sensitivity analysis of a demographic model using life‐stage simulation analysis (LSA) to determine the relative importance of genetic, demographic, environmental, and catastrophic processes on population growth. Annual population growth has been slow and variable (1.0 ± 5.2 parrots per year, or an average λ = 1.05 ± 0.19) from 16 parrots (1973) to a high of 40–42 birds (1997–1998). A risk analysis based on population prediction intervals (PPI) indicates great risk and large uncertainty, with a range of 22–83 birds in the 90% PPI only five years into the future. Four primary factors (reduced hatching success due to inbreeding, failure of adults to nest, nest failure due to nongenetic causes, and reduced survival of adults and juveniles) were responsible for maintaining the bottleneck. Egg‐hatchability rates were low (70.6% per egg and 76.8% per pair), and hatchability increased after mate changes, suggesting inbreeding effects. Only an average of 34% of the population nested annually, which was well below the percentage of adults that should have reached an age of first breeding (41–56%). This chronic failure to nest appears to have been caused primarily by environmental and/or behavioral factors, and not by nest‐site scarcity or a skewed sex ratio. Nest failure rates from nongenetic causes (i.e., predation, parasitism, and wet cavities) were low (29%) due to active management (protecting nests and fostering captive young into wild nests), diminishing the importance of nest failure as a limiting factor. Annual survival has been periodically reduced by catastrophes (hurricanes), which have greatly constrained population growth, but survival rates were high under non‐catastrophic conditions. Although the importance of factors maintaining the Puerto Rican Parrot bottleneck varied throughout the 30‐year period of study, we determined their long‐term influence using LSA simulations to correlate variation in demographic rates with variation in population growth (λ). The bottleneck appears to have been maintained primarily by periodic catastrophes (hurricanes) that reduced adult survival, and secondarily by environmental and/or behavioral factors that resulted in a failure of many adults to nest. The influence of inbreeding through reduced hatching success played a much less significant role, even when additional effects of inbreeding on the production and mortality of young were incorporated into the LSA. Management actions needed to speed recovery include (1) continued nest guarding to minimize the effects of nest failure due to nongenetic causes; (2) creating a second population at another location on the island—a process that was recently initiated—to reduce the chance that hurricane strikes will cause extinction; and (3) determining the causes of the low percentage of breeders in the population and ameliorating them, which would have a large impact on population growth.

The mechanical integrity journey—Equipment identification

AbstractThe development of a functioning mechanical integrity (MI) program is very much like taking a long journey. The first step in that journey is to develop a practical methodology for determining what equipment is to be inspected and tested. When it comes to equipment that contains or handles hazardous materials, this step is crucial from a catastrophic prevention perspective process safety management (PSM), as well as environmental protection and production/cost perspectives.A practical methodology to identify MI equipment for inspection and testing, as well as a table that is used to document MI equipment and tests required were developed and are shared in this article.This article describes an approach that builds on center for chemical process safety guidelines and fulfills both the occupational safety and health administration, process safety management, and environmental protection agency's risk management program regulations, by considering the four following criteria to identify MI equipment: Equipment that provides containment of hazardous materials. Equipment that prevents releases of hazardous materials. Equipment that mitigates releases of hazardous materials. Equipment that supports containment, prevention, or mitigation of releases of hazardous materials. © 2008 American Institute of Chemical Engineers Process Saf Prog, 2008

Flashover Condition Analysis on Passenger Carriage Fire by Using Swallowtail Catastrophe Theory

Flashover in compartment fire itself is a catastrophe process. Its catastrophe behavior can be analyzed, and its topological function equation can also be set up by catastrophe theory. On the basis of analyzing swallowtail catastrophe characteristic, a flashover model of hot smoke layer, which is established based on energy conservation, is transformed in the dimensionless form firstly, and then diffeomorphism is applied to simplify it. By these transform, a catastrophe potential function is gained. The format of the catastrophe potential function makes it clear that this type of flashover belongs to swallowtail catastrophe. Subsequently, taking passenger carriage fire as an idiographic object, the connection between system control variable and burning condition is discussed. The results show that the space of catastrophe bifurcation in muster divide the fire into two section, namely flashover section and non-flashover section. If in flashover section, an unstable point can be obtained by using qualitative curve or differential coefficient curve of potential function. Furthermore, the temperature of hot smoke layer is calculated by the value of the critical point when flashover occurs. The calculation case of passenger carriage fire shows that the temperature of hot smoke layer is 625.3°C when flashover occurs in the carriage, which is agreement with real instance.

Real-time thermal imaging of catastrophic optical damage in red-emitting high-power diode lasers

The dynamics of the catastrophic optical damage process under continuous wave operation is analyzed in red-emitting high-power diode lasers by means of combined thermal and optical near-field (NF) imaging with cameras. The catastrophic process is revealed as extremely fast (Δt⩽2.3ms) and spatially confined. It is connected with a pronounced impulsive temperature change. Its coincidence with the most intense NF filament is indicative of the critical nature of thermal runaway in the catastrophic process.

Coronal Flux Rope Catastrophe Caused by Photospheric Flux Emergence

Photospheric magnetic flux emergence has been often observed in solar active regions and considered to be closely related to solar explosive phenomena such as flares and CMEs. However, in view of the fact that photospheric flux emergence and associated flares or CMEs differ remarkably in timescale, their relationship must be implemented by a catastrophic process. To demonstrate this point, we investigate the catastrophe of a coronal flux rope system caused by photospheric flux emergence. The initial magnetic field is taken to be a two-dimensional force-free field in spherical geometry, consisting of an isolated flux rope and a bipolar background field surrounding it. A flux emergence is then introduced somewhere on the photosphere, and it causes a variation of the background field and the formation of a current sheet between the emerging arcade and the original background field. It is shown that as the total flux of the emerging arcade increases, a catastrophe may take place for the system, depending on the location and field orientation of the emerging arcade and whether there exists a magnetic reconnection across the newly formed current sheet. Although the main conclusions are superficially similar to those obtained by previous studies, we stress an entirely new concept that the photospheric flux emergence plays the role of a trigger rather than a driver of the associated flare and CME by forcing a highly complex system to reach its catastrophic point.

The Earth's dynamic surface: an overview

Debate about the relative roles of catastrophic v. continuous processes of landform evolution is as old as the discipline of Earth Science itself. Over the last 10 years or so, research in the Earth Sciences has focussed strongly on the Earth’s surface and particularly in terms of quantifying rates of processes. This research parallels developments in geomorphology and sedimentology in the quantification of surface processes since the 1950s and 1960s. These surface processes are the manifestation of the large-scale interaction of climate and tectonics operating over a wide range of spatial and temporal scales. Thus, recent research had required integration of the historically distinct subjects of geomorphology, sedimentology, climatology and tectonics. Partly as a cause and partly as a consequence of this integration, there have been many recent developments in quantitative modelling and both laboratory and field-based analytical tools. Together, these have provided new insights into absolute and relative rates of denudation, and the factors that control the many dynamic processes involved. One of the outstanding issues concerns the balance between tectonics, climate and denudation, and in particular the limiting effects of one on the others and the nature of dynamic feedback mechanisms. The fact that processes can be considered catastrophic or continuous, depending on the timescale of observation or interest, can hinder the predictability of models, depending on how they are formulated. Certain conditions may lead to a steady-state situation in which denudation balances tectonic uplift, leading to a more or less constant topography. Steady-state topography means that detailed study of present day landforms can provide important insights into the nature of surface processes back in time. Such assumptions underpin debates in geomorphology relating to the process-form linkage and the understanding of characteristic forms in the landscape. Alternatively, the recognition of non-steady-state situations and a clearer understanding of why these situations occur provide the key for resolving the climate– tectonics–landscape evolution feedback loop. The transition between the two states will reflect the process response time, and therefore the transitory state may provide a clearer picture of the time lag of topographic response to changes in the rates of climate change and tectonic forcing. However, the response time is not necessarily constant and may have changed considerably at key points in the past, such as the evolution of plants on land in the Palaeozoic and the acceleration of human activity within the landscape in the Holocene. In terms of denudation (physical erosion and chemical and mechanical weathering), there are clearly catastrophic processes, such as landsliding, which operate discretely and on short timescales and more continuous processes, such as chemical weathering, which can be considerably more protracted. The distinction between discrete catastrophe and continuous modification depends also on the time and spatial scales of interest. These considerations also impact directly on the questions of if and how steady-state topography can be achieved, how the processes controlling this state can be quantified and resolved, what causes departures from a steady-state condition and how topography reflects the coupling between denudation, climate and tectonics. Some of the key current research areas in the world are tectonically active regions, such as New Zealand (southern Alps), Taiwan and Olympic Mountains (USA). However, the link between tectonics and denudation is complicated in these convergent zones (e.g. Willett et al. 2001), as there is a significant horizontal component to the deformation and, additionally, climatic variations often produce marked asymmetry in denudation, which itself then feedbacks into the isostatic component of vertical motion. In practice, this research field necessarily involves a broad range of disciplines including field geologists, geomorphologists, structural geologists, geochemists, climatologists and geophysical modellers. These researchers address the observational constraints on

Lucifer's Labyrinth—Ten Years of Path Finding in Cell Death

Cell death, as a foil to cell expansion, has become one of the most intensively studied research areas of modern biology. Almost every aspect of life is intimately enmeshed with the proper regulation of cell death, which either contributes to or forms the basis of most human disease pathogenesis. Now, with our ever-expanding knowledge of the various death pathways, comes the hope that we might harness cell death--by either inhibition or promotion--to translate the concepts into cure.

Evolutionary catastrophes and the Goldilocks problem

AbstractOne of the mainstays of the controversial ‘rare Earth’ hypothesis is the ‘Goldilocks problem’ regarding various parameters describing a habitable planet, partially involving the role of mass extinctions and other catastrophic processes in biological evolution. Usually, this is construed as support for the uniqueness of the Earth's biosphere and intelligent human life. Here it is argued that this is a misconstrual and that, on the contrary, observation-selection effects when applied to catastrophic processes make it very difficult for us to discern whether the terrestrial biosphere and evolutionary processes which created it are exceptional in the Milky Way or not. This agnosticism, in turn, supports the validity and significance of practical astrobiological and SETI research.

A synthesis of footloose-entrepreneur new economic geography models: when is agglomeration smooth and easily reversible?

Models of the new economic geography share a number of common conclusions, but also exhibit notable differences, in particular with respect to the shape of the location pattern. Some models imply a catastrophic agglomeration process with hysteresis, so that concentration in one region is not easily reversible. Other models suggest that agglomeration may be smooth, easily reversible and not necessarily feature extreme ‘bang-bang’ outcomes. These differences reflect the fact that new economic geography models have relied heavily on specific functional forms. In this article we approach the properties of a particular class of new economic geography models, the class of ‘footloose entrepreneur models’, with a unifying framework based on the indirect utility function of mobile agents. We are able to provide general, yet handy, formulae to determine the break point and the bifurcation pattern. An application of this framework allows us to show how specific results in the literature can be reconciled as special cases, so that the origin of their differences can be highlighted.

A Note on Extinction Times for the General Birth, Death and Catastrophe Process

We consider a birth, death and catastrophe process where the transition rates are allowed to depend on the population size. We obtain an explicit expression for the expected time to extinction, which is valid in all cases where extinction occurs with probability 1.

A Note on Extinction Times for the General Birth, Death and Catastrophe Process

We consider a birth, death and catastrophe process where the transition rates are allowed to depend on the population size. We obtain an explicit expression for the expected time to extinction, which is valid in all cases where extinction occurs with probability 1.

A Note on Extinction Times for the General Birth, Death and Catastrophe Process

We consider a birth, death and catastrophe process where the transition rates are allowed to depend on the population size. We obtain an explicit expression for the expected time to extinction, which is valid in all cases where extinction occurs with probability 1.

Reasons vs. Causes: Emergence as experienced by the human agent

Because they are in constant interaction with each other, human beings are often agents within emergent collective processes. Although they are then acting as particles in a field-type phenomenon, their awareness of what they are part of entails that they hold views about why they’re acting the way they do, these, they call “reasons.” Should physicists dismiss such “reasons” as being illusory causes of events? “Reasons” are actually important explanatory factors of emergent phenomena involving human beings. Awakening and then responding to a catastrophic process will often signal a bifurcation in the physical emergent process. Coordinated behavior can interrupt a positive feedback by generating a counteracting negative feedback. “Natural” laws were called after “legal” laws; in return, compliance to legal laws by human agents allows their behavior to appear organized, as if by a “natural” law. “Following a rule” conflates the logic of “causes” with that of “reasons” as it connects in phase space the “cause” at the origin (efficient cause) and the “reason” (final cause), the goal that is a representation of the end.

Impact cratering — fundamental process in geoscience and planetary science

Impact cratering is a geological process characterized by ultra-fast strain rates, which generates extreme shock pressure and shock temperature conditions on and just below planetary surfaces. Despite initial skepticism, this catastrophic process has now been widely accepted by geoscientists with respect to its importance in terrestrial — indeed, in planetary — evolution. About 170 impact structures have been discovered on Earth so far, and some more structures are considered to be of possible impact origin. One major extinction event, at the Cretaceous-Paleogene boundary, has been firmly linked with catastrophic impact, but whether other important extinction events in Earth history, including the so-called “Mother of All Mass Extinctions” at the Permian-Triassic boundary, were triggered by huge impact catastrophes is still hotly debated and a subject of ongoing research. There is a beneficial side to impact events as well, as some impact structures worldwide have been shown to contain significant (in some cases, world class) ore deposits, including the gold-uranium province of the Witwatersrand basin in South Africa, the enormous Ni and PGE deposits of the Sudbury structure in Canada, as well as important hydrocarbon resources, especially in North America. Impact cratering is not a process of the past, and it is mandatory to improve knowledge of the past-impact record on Earth to better constrain the probability of such events in the future. In addition, further improvement of our understanding of the physico-chemical and geological processes fundamental to the impact cratering process is required for reliable numerical modeling of the process, and also for the correlation of impact magnitude and environmental effects. Over the last few decades, impact cratering has steadily grown into an integrated discipline comprising most disciplines of the geosciences as well as planetary science, which has created positive spin-offs including the study of paleo-environments and paleo-climatology, or the important issue of life in extreme environments. And yet, in many parts of the world, the impact process is not yet part of the geoscience curriculum, and for this reason, it deserves to be actively promoted not only as a geoscientific discipline in its own right, but also as an important life-science discipline.

Revolutions in the Earth Sciences: Continental Drift, Impact and other Catastrophes

Research Article| March 01, 2007 Revolutions in the Earth Sciences: Continental Drift, Impact and other Catastrophes Wolf Uwe Reimold Wolf Uwe Reimold Museum for Natural History (Mineralogy), Humboldt-University in Berlin, Invalidenstrasse 43, 10115 Berlin, Germany e-mail: uwe.reimold@museum.hu-berlin.de Search for other works by this author on: GSW Google Scholar South African Journal of Geology (2007) 110 (1): 1–46. https://doi.org/10.2113/gssajg.110.1.1 Article history first online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation Wolf Uwe Reimold; Revolutions in the Earth Sciences: Continental Drift, Impact and other Catastrophes. South African Journal of Geology 2007;; 110 (1): 1–46. doi: https://doi.org/10.2113/gssajg.110.1.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu nav search search input Search input auto suggest search filter All ContentBy SocietySouth African Journal of Geology Search Advanced Search Abstract This is the story of changing paradigms, regarding the understanding of our planet and its position in space – of geocentric and heliocentric views, but mainly in the earth sciences, over the last several centuries. This is also the story of the revolutionaries –Copernicus, Lyell, Hutton, Van Hoff, Wegener and Du Toit, Dietz and Hess, and finally Shoemaker. It is the story that begins with the Babylonian geocentric but flat worldview, moves on to the heliocentric perspective of the Greek philosopher Aristarch, via the geocentric dogma of the pre-Copernican Middle Ages and Copernicus’ revision, to the Cataclysm Theory, and then the beginning of Modern Geology in the form of gradualism and actualism, to continental drift that spawned plate tectonics, and finally to Planetary Science. This new view of the universe includes what I would like to call the New Catastrophism, incorporating the catastrophic forces of the important natural catastrophic processes affecting this planet. The nature of impact cratering as a fundamental universal process and the tools for the recognition of impact structures will be examined, and the role of this process since beginning of accretion and planet formation, and leading to the question whether past impact catastrophes have, at times, spurned major mass extinctions in Earth’s biological record. This paper addresses Africa’s impact crater record and the stratigraphic record of impact cratering, and examines both the challenge that humanity is experiencing from huge extraterrestrial bolides and the benefits that impact has brought. In the end, the conclusion is derived that an integrated geoscientific and planetological science approach has resulted in new tools to address the ultimate questions of Earth’s – and our – past and future. You do not currently have access to this article.

The catastrophic geomorphological processes in humid tropical Africa: A case study of the recent landslide disasters in Cameroon

A retrospective analysis of data from the last three decades, clearly indicates an upward trend in the number of landslides and mudflows in Cameroon. Their impact on human beings, environment and properties has increased considerably. For example, since June 2001, several cases have been recorded, among which two resulted in significant human losses: twenty three deaths in June 2001 in Limbe town, twenty five others in July 2003 at Magha and its surroundings in the Bamboutos Mountains. These last two events were really spectacular and may be sounding the alarm of a geomorphological crisis in the region. According to each case, several tens or hundreds of landslides of different types and magnitudes occurred within a few minutes or hours, extending over an area of several tens of square kilometres. The reasons for this catastrophic evolution in the geomorphological processes in Cameroon are natural and anthropogenic. Among others, the natural factors are the changing climatic conditions, with the occurrence of very exceptional rainfalls and the uneven topography of the affected zones, for example with very steep slopes, as in the Magha zone of which area about fifty percent is above twenty degrees. The anthropogenic factors are also very relevant, with the increasing human pressure on the environment, characterised by the extension and/or intensification of the agro-pastoral activities (in the rural areas) and the anarchical settlement on the sloping urban zones.

Birth-multiple catastrophe processes

Birth-multiple catastrophe processes are analyzed where the birth transition rates are assumed to be constant while catastrophes are distinguished by having possibly different destinations and possibly different transition rates. The transient probability functions of such birth-multiple catastrophe systems are determined. The solution method uses dual processes, randomization, and sample path counting. Solutions are explicit in terms of being a finite linear combination of products of exponential functions of time, t, and nonnegative integer powers of t. The coefficients within this expansion follow a pattern of rational functions of the transition rates.

Deposition settings on the continental shelf of the East Siberian Sea

The spacious continental shelf of the East Siberian Sea (ESS) is of particular interest primarily due to its formation in settings of periglacial lithogenesis. This region is characterized by the universal development of Pleistocene permafrost rocks (PFR) [1, 11]. The presence of thick veins of relict ice enclosed in these sequences determined the dependence of the coastalshelf cryolithozone PFR on the thermal and hydrodynamic impact. Under the influence of these factors, the present-day coastal zone is advancing landward at an annual mean rate of 3‐5 m. Consequently, the seawater occupies tens of square kilometers of the former coastal areas of maritime plains [2, 3, 6, 12]. Large volumes of mineral and organic material introduced into shelf waters become involved in sedimentary and biogeochemical cycles. The ESS shelf is known not only for such catastrophic natural processes. It hosts the largest explored and potential reserves of coastalmarine placers and is considered a part of the megaba

Mass-transport complexes and associated processes in the offshore area of Trinidad and Venezuela

Mass-transport complexes (MTCs) form a significant component of the stratigraphic record in ancient and modern deep-water basins worldwide. One such basin, the deep-marine margin of eastern offshore Trinidad, situated along the obliquely converging boundary of the Caribbean and South American plates and proximal to the mouth of the Orinoco River, is characterized by catastrophic shelf-margin processes, intrusive and extrusive mobile shales, active tectonics, and possible migration and sequestration of hydrocarbons. Major structural elements found in the deep-water slope regions include large transpressional fault zones (i.e., Darien Ridge, Central Range, Los Bajos), along which mobile shales extrude to form sea-floor ridges; fault-cored anticlinal structures overlain by extrusive sea-floor mud volcanoes; shallow-rooted sediment bypass grabens near the shelf break; and normal and counterregional faults. A total of 10,708 km2 (4134-mi2) of merged three-dimensional (3-D) seismic surveys enable sub-sea-floor interpretation of several erosional surfaces that form the boundaries of enormous mass-transport complexes. The data show numerous episodes of MTC developments, which are characterized by chaotic, mounded seismic facies and fanlike geometry. Their extent (up to 2017 km2 [778 mi2]) and thickness (up to 250 m [820 ft]) is strongly influenced by sea-floor topography. Mass-transport flows show runout distances from the source area of 60–140 km (37–86 mi). Depositional architecture identified with these units includes (1) large-magnitude lateral erosional edges, (2) linear basal scours, and (3) side-wall failures. Mud volcanoes act as barriers to cross-slope mass sediment movements and form zones of shadowing on their downslope side that protect those regions from erosion. The subsequent erosional shadow remnants (ESRs) comprise preserved regions of older levee-channel complex sediments and are considered for the first time in this study as potential stratigraphic traps in deep-water deposits. Active tectonism in the region, high sedimentation rates associated with the Orinoco delta system, and abundant potential unstable hydrate suggest the viable presence of several higher frequency mechanisms at work for MTC generation than sea level fluctuations alone.

Influence of the acetolactate synthase inhibitor metsulfuron-methyl on the operation, regulation and organisation of photosynthesis in Solanum nigrum

The influence of the acetolactate synthase inhibitor metsulfuron-methyl on the operation of the photosynthetic apparatus was examined on 4-weeks-old climate chamber-grown Solanum nigrum plant. To have an indication on the relative performance of the photosynthetic apparatus of ALS-treated plants, the level of carbon dioxide (CO(2)) fixation, the relative quantum efficiency of photosystem I (Phi(PSI)) or photosystem II (Phi(PSII)) electron transport and leaf chlorophyll content were assessed for both control and treated plants at 2, 4 and 7 days after application of the herbicide. Results indicated a progressive inhibition of the level of CO(2) fixation, the relative quantum efficiency of photosystem I (Phi(PSI)) and II (Phi(PSII)) electron transport and the leaf chlorophyll content already 2 days after application of the herbicide. The linear relationship between the photosystem I and II was unaltered by herbicidal treatment and was sustained under conditions where large changes in pigment composition of the leaves occurred. It appears that the stress-induced loss of leaf chlorophyll is not a catastrophic process but rather is the consequence of a well-organised breakdown of components. Under photorespiratory and non-photorespiratory conditions, the relationship between the index of electron transport flow through photosystem I and II and the rate of CO(2) fixation is altered so that electron transport becomes less efficient at driving CO(2) fixation.