5,555 research outputs found

    Modelling the impacts of wildfire on the viability of metapopulations of the endangered Australian species of arboreal marsupial, Leadbeater's Possum

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    Catastrophic events such as intensive wildfires have a major effect on the dynamics of some wildlife populations. In this investigation, the computer package ALEX (Analysis of the Likelihood of EXtinction), was used to simulate the impacts of wildfires on the persistence of metapopulations of the endangered species Leadbeater's possum (Gymnobelideus leadbeateri) which is restricted to the montane ash forests of the Central Highlands of Victoria. A range of scenarios was examined. First, the response of G. leadbeateri to tires in hypothetical patches of old growth forest of varying size was modelled. Metapopulation dynamics were then modelled in four existing forest management areas: the O'Shannassy Water Catchment and the Steavenson, Ada and Murrindindi Forest Blocks using GIS-derived forest inventory data on complex spatial arrangements of potentially suitable old growth habitat patches. The impacts of different fire frequencies and the proportion of forest area that was burnt in the Steavenson Forest Block and the O'Shannassy Water Catchment were examined. Finally, the combined impacts of both wildfires and post-fire salvage logging operations on the persistence of populations of G. leadbeateri were assessed. Our analyses indicated that, even in the absence of wildfires, populations of G. leadbeateri are very susceptible to extinction within single isolated habitat patches of 20 ha or less. The probability of persistence approached 100% in patches of 250 ha. The incorporation of the effects of wildfire was predicted to have a major negative impact on isolated populations of G. leadbeateri. In these cases, the probability of population extinction remained above 60%, even when a single patch of 1200 ha of old growth forest was modelled. In the absence of wildfires, there was a low probability of extinction of G. leadbeateri in the O'Shannassy Water Catchment where very large patches of old growth forest presently exist. The risk of extinction of the species was significantly higher in the Murrindindi and Ada Forest Blocks where there are lower total areas of, and significantly smaller, suitable habitat patches. Wildfires resulted in an increase in the predicted probability of metapopulation extinction in the four areas that were targeted for study. An investigation of the Steavenson Forest Block and the O'Shannassy Water Catchment revealed that the predicted values for the probability of extinction were sensitive to inter-relationships between the frequency of fires and the proportion of habitat patches that were burnt during a given fire event. The probability of extinction of G. leadbeateri was predicted to be lowest when there were frequent fires that burnt only relatively small areas of a given forest block. Conversely, the results of our analyses suggested that populations of the species are vulnerable to infrequent but intensive conflagrations that burnt a large proportion of the forest. The results of the suite of analyses completed in this study suggest hat four management strategies will be important for the long-term conservation of G. leadbeateri. (1) Attempts to suppress wildfires should be maintained as even the largest remaining areas of old growth forest may be susceptible to being burnt by repeated widespread wildfires that could result in localised and/or global extinction of the species. (2) Because the probability of population persistence is greatest in those areas that support more extensive stands of old growth forest, it will be important to grow relatively large patches of existing regrowth forest (over 50 ha) through to ecological maturity. This will be particularly important in some wood production forest blocks where there are only limited areas of old growth forest. (3) Patches that are set aside for the conservation of G. leadbeateri should be spatially separated to minimise the risk that all of the reserved areas in a region are destroyed in a single major fire event. (4) Salvage logging operations should be excluded from stands of old growth forest and reserved areas that are burnt in a wildfire. This is because such activities can have a major negative impact of the development of suitable habitat for G. leadbeateri

    Plantation forests and biodiversity conservation

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    There are five key reasons why biodiversity conservation should be considered a part of plantation management. (1) The plantation estate is large, and balancing various land management values with wood and pulp production is important when extensive areas of land are involved. (2) The locations and management of new plantations will affect the biota that currently exist in such landscapes. (3) Maintaining some elements of biodiversity within plantations can have benefits for stand productivity and the maintenance of key ecosystem processes such as pest control. (4) The retention (or loss) of biota in plantations is relevant to the formulation of ecological standards and the certification of plantations in many parts of the world. (5) Plantation forestry has a narrow and intensive management focus on producing a forest crop for a limited array of purposes. It will not meet future societal demands for a range of outputs from plantations (in addition to wood and pulp supply), and will not be congruent with the principles of ecological sustainability. This paper briefly reviews the biodiversity conservation values of Australian plantation s. It shows that almost all work in Australian plantations, whether conifer or eucalypt, highlights the importance of landscape heterogeneity and stand structural complexity for enhancing biodiversity. Management of plantations to promote landscape heterogeneity and stand structural complexity and enhance the conservation of biodiversity will, in many cases, involve tradeoffs that will affect wood and pulp production. The extent to which this occurs will depend on the objectives of plantation management and how far they extend towards the more complex plantation forestry models that incorporate social and environmental values. We argue that the widespread adoption of plantation forestry that leads to homogenous stands of extensive monocultures will risk re-creating the array of negative environmental outcomes that have been associated with agriculture in many parts of Australia

    The Conservation Of Arboreal Marsupials In The Montane Ash Forests Of The Central Highlands Of Victoria, South-Eastern Australia - VII. Modelling The Persistence Of Leadbeater's Possum In Response To Modified Timber Harvesting Practices

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    A computer model for Population Viability Analysis (PVA) was used to simulate the relationship between the persistence of populations of the endangered species, Leadbeater's possum, Gymnobelideus leadbeateri and the implementation of a range of possible modified timber harvesting practices in two wood production blocks within the montane ash forests of the central highlands of Victoria, south-eastern Australia. The results of our analyses revealed that under the existing conservation strategies there was a high probability of extinction over the next 150 years in both blocks. Given that timber production areas comprise more than 75% of the distribution of G. leadbeateri, our findings highlight a need for additional conservation measures to enhance the survival prospects of the species. The range of upgraded conservation strategies that were examined included (1) extending the rotation time between logging operations; (2) modifying silvicultural practices to increase the amount of forest retained within each harvested coupe; and (3) permanently withdrawing areas from wood production. All of each of these approaches were found significantly to reduce the probability of extinction of populations of G. leadbeateri. However, when the relative merits of the various strategies were compared, the permanent withdrawal of potential logging coupes from timber harvesting was predicted to be the most efficient approach. Importantly, this strategy would have a number of practical advantages including that it overcomes both (1) the logistic difficulties of ensuring the long-term survival of retained trees within logged areas; and (2) human safety issues arising from implementing modified silvicultural practices. This practical application of PVA to compare the merits of different potential management options has provided new information that will enhance present efforts to conserve G. leadbeateri in wood production areas

    Maintaining an expert system for the Hubble Space Telescope ground support

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    The transformation portion of the Hubble Space Telescope (HST) Proposal Entry Processor System converts astronomer-oriented description of a scientific observing program into a detailed description of the parameters needed for planning and scheduling. The transformation system is one of a very few rulebased expert systems that has ever entered an operational phase. The day to day operations of the system and its rulebase are no longer the responsibility of the original developer. As a result, software engineering properties of the rulebased approach become more important. Maintenance issues associated with the coupling of rules within a rulebased system are discussed and a method is offered for partitioning a rulebase so that the amount of knowledge needed to modify the rulebase is minimized. This method is also used to develop a measure of the coupling strength of the rulebase

    Oxidative metabolism and absorption spectra of anaerobically grown yeast. Manometric data and absolute absorption spectra

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    No Abstract.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/50120/1/1030530110_ftp.pd

    Long-acting injectable antipsychotics: focus on olanzapine pamoate

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    Medication non-adherence in patients with schizophrenia continues to be a significant problem and threatens successful treatment outcomes. Medication non-adherence is often associated with negative consequences, including symptom exacerbation, more frequent emergency room visits, re-hospitalizations and relapse. Long-acting injectable (LAI) forms of antipsychotics allow for rapid identification of non-adherence, obviate the need for the patient to take the medication on a daily basis and increase adherence to some significant degree. Eli Lilly has developed a long-acting depot formulation of olanzapine, olanzapine pamoate, which has recently been approved by the FDA for the US market, and which will be reviewed here. Olanzapine LAI appears to be an effective antipsychotic at dosages of 210 mg every 2 weeks, 300 mg every 2 weeks and 405 mg every 4 weeks in patients with acute schizophrenia, and at 150 mg every 2 weeks, 300 mg every 2 weeks and at 405 mg every 4 weeks for the maintenance treatment of stable patients. Oral supplementation appears not to be needed, particularly not at the onset of treatment with the LAI as is necessary with risperidone LAI. Its efficacy is in general comparable to the efficacy seen with oral olanzapine at a corresponding dose. The side effect profile is also comparable to the side effects observed with oral olanzapine, including lower rates of extrapyramidal symptoms, prolactin elevation and cardiovascular side effects, but significant metabolic effects. The latter include significant weight gain, lipid abnormalities and glucose dysregulation. While the injection site adverse events are overall mild, the most significant serious adverse event is the post-injection delirium sedation syndrome (PDSS). While rare, this syndrome results from inadvertent intravascular injection of olanzapine LAI and can cause a range of olanzapine overdose-type of symptoms. Olanzapine LAI needs therefore to be administered by trained personnel in settings where a post-injection observation period for at least 3 hours by medical personnel is available. The overall use of olanzapine LAI will probably be limited by the possibility of a PDSS event. Patients who have a history of good response to oral olanzapine and are in need of assured medication administration may present a good indication for its use, provided that the appropriate mental health delivery setting is available

    Commentary: Continental-level biodiversity collapse

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    Biodiversity loss is a global phenomenon, with Woinarski et al. providing a sobering review of the demise of the Australian native terrestrial mammal fauna. The authors’ focus is on the loss of >10% of endemic terrestrial native mammal fauna since European settlement in 1788. The extent of mammal loss is highlighted by the contrast with mainland North America, with just one mammal species extinction in the equivalent ∼200-y period. Woinarski et al. make key points about conservation policies and practices, some of which have global implications

    Salobo Sequence, Carajas, Brazil: Geology, Geochemistry And Metamorphism

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    The Salobo Cu (Au, Ag, Mo) deposit is in the Carajas basin, located in the eastern Amazon craton, southern Para state, Brazil.;The Salobo sequence at the deposit area comprises metamorphosed basaltic rocks, iron formations, graywackes and arkosic arenites deposited at 2758+/-2 Ma on a trondhjemitic basement dated at 2851+/-4 Ma. The amphibolites are continental tholeiitic basalts, indicated by Fe, LIL and LREE enrichment, LREE fractionation and almost flat HREE chondrite-normalized patterns. Silicate-type iron formation grades to an aluminous type and finally to metagraywackes. Geochemical studies show a continuous compositional variation between both iron formation types, with gradual Al, K, Ti and Zr increase and Fe and Si decrease, defining a mixing line between chemical iron formation and volcaniclastic contaminants of the Grao Para Group.;The highly fractionated REE chondrite-normalized pattern of Type I iron formation (La/Lu{dollar}\sb{lcub}\rm cn{rcub}{dollar} = 440) and strong positive Eu anomaly (Eu/Eu* = 6.3) indicate a hydrothermal origin. Hydrothermal provenance for Cu is indicated by a positive correlation between Fe and Cu.;The Salobo sequence underwent progressive metamorphism close to pyroxene hornfels facies, followed by two episodes of hydrothermal alteration, at amphibolite and greenschist facies. The first metamorphic episode took place at low pressure (2-3 kbar) with a temperature of 750{dollar}\sp\circ{dollar}C (garnet-hornblende geothermometer); the associated fluids had P{dollar}\sb{lcub}\rm CO2{rcub}{dollar} {dollar}\u3e{dollar} P{dollar}\sb{lcub}\rm H2O{rcub}{dollar} and log f{dollar}\sb{lcub}\rm O2{rcub}{dollar} from {dollar}-{dollar}18 to {dollar}-{dollar}22. Garnet-biotite and muscovite-biotite geothermometers indicate temperatures of 650 and 550{dollar}\sp\circ{dollar}C for the first hydrothermal alteration episode. The garnet-plagioclase geobarometer shows a pressure of 2.5 kbar for this event, which is also the pressure of the first metamorphism. Mass balance calculations indicate that related fluids were slightly oxidizing, acidic and highly saline promoting hydration accompanied by leaching of Ca and deposition of Si, K, Na and B. The temperature during the second hydrothermal episode was 370{dollar}\sp\circ{dollar}C (garnet-biotite geothermometer). Mass balance calculations show that the associated fluids were acidic, oxidizing, with moderate salinity, depositing Si and leaching Na, K and Mn. The lower temperature (550{dollar}\sp\circ{dollar}C) stage of the first hydrothermal event and the second hydrothermal episode occurred at the time interval of 2581-2551 Ma, which also represents the age of basement ascent

    Small patches make critical contributions to biodiversity conservation

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    Vast areas of the earth's land surface have been altered by human activities such as clearing native vegetation for agriculture and livestock grazing, logging of natural forests, and land conversion for urban settlements (1). These activities have had profound impacts on biodiversity and on key ecosystem processes (e.g. pollination and nutrient cycling) (2). Many ecosystems have been markedly reduced in extent (often termed habitat loss) (3, 4) with remaining areas sub-divided into small, isolated remnants (typically termed habitat fragmentation) (see (5)). In PNAS, Wintle et al. (6) explore some new perspectives associated with the conservation value of small, isolated remnants and demonstrate they are more important for biodiversity conservation than often recognized
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