887 research outputs found

    Stratospheric sudden warmings in an idealized GCM

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    PublishedJournal ArticleAn idealized general circulation model (GCM) with an analytically described Newtonian cooling term is employed to study the occurrence rate of sudden stratospheric warmings (SSWs) over a wide range of parameters. In particular, the sensitivity of the SSW occurrence rates to orographic forcing and both relaxation temperature and damping rate is evaluated. The stronger the orographic forcing and the weaker the radiative forcing (in both temperature and damping rate), the higher the SSW frequency. The separate effects of the damping rates at low and high latitudes are somewhat more complex. Generally, lower damping rates result in higher SSW frequency. However, if the low- and high-latitude damping rates are not the same, SSW frequency tends to be most sensitive to a fractional change in the lower of the two damping rates. In addition, the effect of the damping rates on the stratospheric residual circulation is investigated. It is found that higher high-latitude damping rate results in deeper but narrower circulation, whereas higher low-latitude damping rates cause strengthening of the stream function in the tropical midstratosphere to upper stratosphere. Finally, the relation between easily measured and compared climatological fields and the SSW occurrence rate is determined. The average stratospheric polar zonal mean zonal wind shows a strong anticorrelation with the SSW frequency. In the troposphere, there is a high correlation between the meridional temperature gradient and SSW frequency, suggesting that the strength of synoptic activity in the troposphere may be an important influence on SSW occurrence.National Science FoundationSwiss National Science Foundatio

    Feeding in the adult of Hermetia illucens (Diptera Stratiomyidae): reality or fiction?

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    Hermetia illucens(L.) (Diptera Stratiomyidae) is a promising species as alternative protein source for animal feed, able to convert a wide range of organic materials. The knowledge on larval biology, development, nutritional needs, and nutritional composition is rich, while few information is available on adult traits. The aim of the present study was to investigate the influence of the adult nutrition on the survival, the longevity and the ovaries development of H. illucens. In detail, three food sources have been compared to starvation. Water, a sucrose solution and a protein solution were given to new emerged adults and data on longevity and ovary development were acquired. Trials were conducted on single specimen and on a cohort of adults. In all the trials, starved adults survived significantly shorter than all other thesis. When adults were maintained isolated, the survival was significantly influenced by the nourishment: longevity was longer when adults were feed with a sucrose solution, while the supply of a protein source provideda lifespan significantly higher than starvation but similar to water or to sucrose solution. In cages longevity was always shorter than in isolated adults for both males and females and the overall trend was similar to single individual trials with the exception of protein solution. Ovary development of females under different nourishment did not show differences.More studies are necessary to identify a correct nutritionconsideringthe integration of different chemical compounds to obtain optimal adult performancein terms of longevity and reproduction

    Understanding trichopria drosophilae performance in laboratory conditions

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    The recent worldwide interest in the invasive pest Drosophila suzukii (Matsumura) has risen the interest to its biological control agents. Among the parasitoids, Trichopria drosophilae (Perkins) is a cosmopolitan species found in association with the pest in different countries. As different populations of the parasitoid can adapt to different geographical areas, this study is focused to deepen the effect of temperature and host on an Italian population. The performance of T. drosophilae was studied under controlled conditions at seven constant temperatures (5-40 \ub0C), and on two hosts, the native Drosophila melanogaster (Meigen) and the invasive D. suzukii. Information on survival, oviposition and sex ratio were acquired for all temperatures. A GLM analysis showed the influence of temperature and host species on the biological parameters analysed. The best performance in terms of fertility and offspring production were obtained between 25 and 30 \ub0C, while the upper thermal limit for the adult survival was identified at 40 \ub0C. Finally, two equations useful to help predictive models have been obtained. We conclude that T. drosophilae has the potential to be efficiently mass-reared at 25 \ub0C

    Pheromone-mediated mating disruption of the European grain moth Nemapogon granellus in ham factories

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    Nemapogon granellus is a lepidopteran species that can cause significant damage to stored animal products such as meats, sausages and cheeses. In the warehouses where such products are stored, pheromone-based control ap-proaches can avoid or reduce insecticide chemical treatments and be more effective than traditional control methods. This study aimed to evaluate the effectiveness of mating disruption (MD) techniques to control N. granellus populations in ham factories. Trials were conducted in two factories located in Northern Italy. In both locations two warehouses were selected: a warehouse test where dispensers, loaded with 10 mg of N. granellus pheromone, were deployed at a density ranging from 1 unit/22.5 m3 (factory A) to 1 unit/25 m3 (factory B), and a control warehouse left untreated. To assess the mating disruption efficacy, the reduction of the number of mated females in water traps, placed in control and treated warehouses, was used as main parameter. The results indicated a substantial reduction in mated females in the treated warehouses in comparison with control warehouses in both the sites of experiments. In detail, the total number of mated females sampled in water traps was above 90% in control warehouses, in warehouses treated with MD technique this percentage was below 50%. In addition, a "trap shutdown" effect was recorded in MD treated warehouses of both factories. These findings suggest that mating disruption is a promising technique that can be positively applied in the integrated pest management of N. granellus in ham factories

    Evaluation of a therapy protocol for the treatment of chronic digital dermatitis in European bison (Bison bonasus)

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    Digital dermatitis (DD) associated with the presence of multiple Treponema spp. was recently described for the first time in European bison (Bison bonasus). DD is characterized by skin inflammation in the distal foot area in various ungulates. The objective of this proof of concept study was to test a treatment protocol adopted from cattle for its applicability in this wildlife species using five animals. Keratolytic salicylic acid paste was administered topically under bandages for seven days to enable removal of the

    Power requirements for electron cyclotron current drive and ion cyclotron resonance heating for sawtooth control in ITER

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    13MW of electron cyclotron current drive (ECCD) power deposited inside the q = 1 surface is likely to reduce the sawtooth period in ITER baseline scenario below the level empirically predicted to trigger neo-classical tearing modes (NTMs). However, since the ECCD control scheme is solely predicated upon changing the local magnetic shear, it is prudent to plan to use a complementary scheme which directly decreases the potential energy of the kink mode in order to reduce the sawtooth period. In the event that the natural sawtooth period is longer than expected, due to enhanced alpha particle stabilisation for instance, this ancillary sawtooth control can be provided from > 10MW of ion cyclotron resonance heating (ICRH) power with a resonance just inside the q = 1 surface. Both ECCD and ICRH control schemes would benefit greatly from active feedback of the deposition with respect to the rational surface. If the q = 1 surface can be maintained closer to the magnetic axis, the efficacy of ECCD and ICRH schemes significantly increases, the negative effect on the fusion gain is reduced, and off-axis negative-ion neutral beam injection (NNBI) can also be considered for sawtooth control. Consequently, schemes to reduce the q = 1 radius are highly desirable, such as early heating to delay the current penetration and, of course, active sawtooth destabilisation to mediate small frequent sawteeth and retain a small q = 1 radius.Comment: 29 pages, 16 figure

    Drivers of aboveground wood production in a lowland tropical forest of West Africa:teasing apart the roles of tree density, tree diversity, soil phosphorus, and historical logging

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    This is the author accepted manuscript. It is currently under an indefinite embargo pending publication by Wiley.1. Tropical forests currently play a key role in regulating the terrestrial carbon cycle and abating climate change by storing carbon in wood. However, there remains considerable uncertainty as to whether tropical forests will continue to act as carbon sinks in the face of increased pressure from expanding human activities. Consequently, understanding what drives productivity in tropical forests is critical. 2. We used permanent forest plot data from the Gola Rainforest National Park (Sierra Leone) – one of the largest tracts of intact tropical moist forest in West Africa – to explore how (i) stand basal area and tree diversity, (ii) past disturbance associated with past logging and (iii) underlying soil nutrient gradients interact to determine rates of aboveground wood production (AWP). We started by statistically modelling the diameter growth of individual trees and used these models to estimate AWP for 142 permanent forest plots. We then used structural equation modelling to explore the direct and indirect pathways which shape rates of AWP. 3. Across the plot network, stand basal area emerged as the strongest determinant of AWP, with densely packed stands exhibiting the fastest rates of AWP. In addition to stand packing density, both tree diversity and soil phosphorus content were also positively related to productivity. By contrast, historical logging activities negatively impacted AWP through the removal of large trees, which contributed disproportionately to productivity. 4. Synthesis. Understanding what determines variation in wood production across tropical forest landscapes requires accounting for multiple interacting drivers – with stand structure, tree diversity and soil nutrients all playing a key role. Importantly, our results also indicate that logging activities can have a long-lasting impact on a forest’s ability to sequester and store carbon, emphasizing the importance of safeguarding old-growth tropical forests.This study was funded through a grant from the Cambridge Conservation Initiative Collaborative Fund entitled “Applications of airborne remote sensing to the conservation management of a West African National Park”. T.J. was funded in part through NERC grant NE/K016377/1. A.C.S. was funded in part through a grant from the Percy Sladen Memorial Fund

    Sustainability, systems thinking and professional practice

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    This article explores the impact of the new sustainability agenda on the occupational and professional needs of those who have taken educational and training programmes in the environmental field either at undergraduate or postgraduate level or through relevant professional institutions' continuing professional development programmes. It also describes a one-day workshop for the professionals on sustainable development, based on systems thinking and practice. The workshop provides a model for developing greater understanding and effective action in professional practice, by using dialogue and interprofessional learning to explore approaches to sustainability in a variety of business and professional contexts. It introduces the principles underpinning the concept of sustainability and provides tools to support the integration of sustainable development into professional practice and organisational change

    Can exotic drosophilids share the same niche of the invasive Drosophila suzukii?

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    The presence of the four exotic drosophilids Chymomyza amoena (Loew),Drosophila suzukii (Matsumura), Zaprionus indianus (Gupta) and Zaprionus tuberculatus Mallochhas been investigated in different orchardsin Northern Italy for two consecutive years. The presence and the abundance of the population of the drosophilid flies were surveyed with apple cider vinegar traps, fruit baited traps, and fruit collection. Chymomyzaamoena, Z. tuberculatusand D. suzukiihave been identified in the ACV traps in both years. Only D. suzukiiand Z. tuberculatusemergedfrom fruit baited traps. Except forD. suzukii,no other exotic drosofilid wascaptured from the fruit collection.Z. indianuswas never observed.Analyses of the presence of the different species, seasonal occurrenceand sex ratio are provided
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