Sparking limits, cavity loading, and beam breakup instability associated with high-current rf linacs

International Nuclear Information System (INIS)

Faehl, R.J.; Lemons, D.S.; Thode, L.E.

1982-01-01

The limitations on high-current rf linacs due to gap sparking, cavity loading, and the beam breakup instability are studied. It appears possible to achieve cavity accelerating gradients as high as 35 MV/m without sparking. Furthermore, a linear analysis, as well as self-consistent particle simulations of a multipulsed 10 kA beam, indicated that only a negligible small fraction of energy is radiated into nonfundamental cavity modes. Finally, the beam breakup instability is analyzed and found to be able to magnify initial radial perturbations by a factor of no more than about 20 during the beam transit time through a 1 GeV accelerator

The impact of resource limitation and the phenology of parasitoid attack on the duration of insect herbivore outbreaks.

Science.gov (United States)

Umbanhowar, James; Hastings, Alan

2002-11-01

Fluctuations in resource quality and quantity, and changes in mortality due to predators and parasites are thought to be of prime importance in the regular fluctuations of forest insects. We examine how food limitation and parasitoids with different phenologies of attack regulate the population cycles of insect hosts. Our analysis of the limit cycle of a model with a biologically realistic form of density dependence in the host yields two novel predictions. First, outbreaks will typically last for only 2 generations after parasitoids begin to reduce the host population below the maximum density. Second, host growth rate is important in determining cycle length only when parasitoids attack before the impacts of resource limitation affect the host. The robustness of these predictions are tested using a more general form of density dependence in the host, revealing that our predictions are valid as long as density dependence in the host is not too overcompensatory.

Beta-limiting MHD instabilities in improved performance NSTX spherical torus plasmas

International Nuclear Information System (INIS)

Menard, J.E.; Bell, M.G.; Bell, R.E.

2003-01-01

Global magnetohydrodynamic stability limits in the National Spherical Torus Experiment (NSTX) have increased significantly recently due to a combination of device and operational improvements. First, more routine H-mode operation with broadened pressure profiles allows access to higher normalized beta and lower internal inductance. Second, the correction of a poloidal field coil induced error-field has largely eliminated locked tearing modes during nor- mal operation and increased the maximum achievable beta. As a result of these improvements, peak beta values have reached (not simultaneously) β t = 35%, β N 6.5, N > = 4.5, β / l i =10, and β= 1.4. High β P operation with reduced tearing activity has allowed a doubling of discharge pulse-length to just over 1 second with sustained periods of β N ∼ 6. Details of the β limit scalings and β-limiting instabilities in various operating regimes are described. (author)

Are altitudinal limits of equatorial stream insects reflected in their respiratory performance?

DEFF Research Database (Denmark)

Jacobsen, Dean; Brodersen, Klaus Peter

2008-01-01

.6 between genera at 17 °C, and from 1.3 to 2.5 at 5 °C. Q10 values for this temperature interval ranged 1.5-2.9 (mean 2.3). The two "high-altitude" genera had higher respiration rates at low temperature and oxygen saturation, and their respiration rate saturated at lower temperatures, than three of the four......-term physiological tolerance of low temperature and oxygen concentration. 5. Multiple regressions (based on respiration experiments and previously obtained relationships between water temperature, oxygen saturation and altitude) were used to predict how respiration rates should vary with altitude. At the upper limit...... saturation. Further quantitative and long-term studies on survival and recruitment in populations and communities are needed to determine the importance of temperature and oxygen for altitudinal limits of aquatic insects....

Microbiological Load of Edible Insects Found in Belgium.

Science.gov (United States)

Caparros Megido, Rudy; Desmedt, Sandrine; Blecker, Christophe; Béra, François; Haubruge, Éric; Alabi, Taofic; Francis, Frédéric

2017-01-13

Edible insects are gaining more and more attention as a sustainable source of animal protein for food and feed in the future. In Belgium, some insect products can be found on the market, and consumers are sourcing fresh insects from fishing stores or towards traditional markets to find exotic insects that are illegal and not sanitarily controlled. From this perspective, this study aims to characterize the microbial load of edible insects found in Belgium (i.e., fresh mealworms and house crickets from European farms and smoked termites and caterpillars from a traditional Congolese market) and to evaluate the efficiency of different processing methods (blanching for all species and freeze-drying and sterilization for European species) in reducing microorganism counts. All untreated insect samples had a total aerobic count higher than the limit for fresh minced meat (6.7 log cfu/g). Nevertheless, a species-dependent blanching step has led to a reduction of the total aerobic count under this limit, except for one caterpillar species. Freeze-drying and sterilization treatments on European species were also effective in reducing the total aerobic count. Yeast and mold counts for untreated insects were above the Good Manufacturing Practice limits for raw meat, but all treatments attained a reduction of these microorganisms under this limit. These results confirmed that fresh insects, but also smoked insects from non-European trades, need a cooking step (at least composed of a first blanching step) before consumption. Therefore, blanching timing for each studied insect species is proposed and discussed.

Microbiological Load of Edible Insects Found in Belgium

Directory of Open Access Journals (Sweden)

Rudy Caparros Megido

2017-01-01

Full Text Available Edible insects are gaining more and more attention as a sustainable source of animal protein for food and feed in the future. In Belgium, some insect products can be found on the market, and consumers are sourcing fresh insects from fishing stores or towards traditional markets to find exotic insects that are illegal and not sanitarily controlled. From this perspective, this study aims to characterize the microbial load of edible insects found in Belgium (i.e., fresh mealworms and house crickets from European farms and smoked termites and caterpillars from a traditional Congolese market and to evaluate the efficiency of different processing methods (blanching for all species and freeze-drying and sterilization for European species in reducing microorganism counts. All untreated insect samples had a total aerobic count higher than the limit for fresh minced meat (6.7 log cfu/g. Nevertheless, a species-dependent blanching step has led to a reduction of the total aerobic count under this limit, except for one caterpillar species. Freeze-drying and sterilization treatments on European species were also effective in reducing the total aerobic count. Yeast and mold counts for untreated insects were above the Good Manufacturing Practice limits for raw meat, but all treatments attained a reduction of these microorganisms under this limit. These results confirmed that fresh insects, but also smoked insects from non-European trades, need a cooking step (at least composed of a first blanching step before consumption. Therefore, blanching timing for each studied insect species is proposed and discussed.

Continental drift and climate change drive instability in insect assemblages

OpenAIRE

Li, Fengqing; Tierno de Figueroa, Jos? Manuel; Lek, Sovan; Park, Young-Seuk

2015-01-01

Global change has already had observable effects on ecosystems worldwide, and the accelerated rate of global change is predicted in the future. However, the impacts of global change on the stability of biodiversity have not been systematically studied in terms of both large spatial (continental drift) and temporal (from the last inter-glacial period to the next century) scales. Therefore, we analyzed the current geographical distribution pattern of Plecoptera, a thermally sensitive insect gro...

A probabilistic method for determining effluent temperature limits for flow instability for SRS reactors

International Nuclear Information System (INIS)

Hardy, B.J.; White, A.M.

1990-06-01

This manual describes the uncertainty analysis used to determine the effluent temperature limits for a Mark 22 charge in the Savannah River Site production reactors. The postulated accident scenario is a DEGB/LOCA resulting from a coolant pipe break at the plenum inlet accompanied by the safety rod failure described in the previous chapter. The analysis described in this manual is used to calculate the limits for the flow instability phase of the accident. For this phase of the accident, the limits criterion is that the Stanton number does not exceed 0.00455 [1]. The limits are determined for a specified 84% probability that the Stanton number will not exceed 0.00455 in any assembly in the core

A probabilistic method for determining effluent temperature limits for flow instability for SRS reactors

Energy Technology Data Exchange (ETDEWEB)

Hardy, B.J.; White, A.M.

1990-06-01

This manual describes the uncertainty analysis used to determine the effluent temperature limits for a Mark 22 charge in the Savannah River Site production reactors. The postulated accident scenario is a DEGB/LOCA resulting from a coolant pipe break at the plenum inlet accompanied by the safety rod failure described in the previous chapter. The analysis described in this manual is used to calculate the limits for the flow instability phase of the accident. For this phase of the accident, the limits criterion is that the Stanton number does not exceed 0.00455 [1]. The limits are determined for a specified 84% probability that the Stanton number will not exceed 0.00455 in any assembly in the core.

Numerical procedure for determining pressure limits on borehole instability problems; Procedimento numerico para determimacao dos limites de pressao em problemas de instabilidade de pocos de petroleo

Energy Technology Data Exchange (ETDEWEB)

Muller, A.L. [Pontificia Univ. Catolica do Rio de Janeiro (PUC-Rio), RJ (Brazil). Grupo de Tecnologia em Computacao Grafica (TecGraf); Vargas Junior, E.A. [Pontificia Univ. Catolica do Rio de Janeiro (PUC-Rio), RJ (Brazil). Dept. de Engenharia Civil; Vaz, L.E. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Escola de Engenharia. Dept. de Mecanica Aplicada e Estruturas; Goncalves, C.J. [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)

2008-07-01

In the boreholes projects, the minimization of the instability problems is extreme importance. In the boreholes instability analysis, two failure mechanisms are generally considered, namely, failure due to either tensile or compressive stresses. Considering these mechanisms, the correct determination of the lower and upper limits of pressures, generated by the drilling fluid in the walls of the boreholes, is an alternative for minimization of the instability problems. The mechanisms of compression or tensile failure can be described in terms of mechanical and fluid flow responses of the transient fluid mechanical coupling problem. This paper proposes a numerical procedure, using finite elements, of the coupled fluid mechanical processes, for automatically determining the lower and upper limits of pressures on the walls of borehole, to ensure, according assumptions and criteria of failure pre-established, the stability of the same. The automatic obtaining those values has the purpose of replace the approximate obtaining by trial and error processes. A hypothetical example of application is show, and from this, inferred considerations about the proposed procedure. (author)

The risk of PCI damage to 8x8 fuel rods during limit cycle instability

Energy Technology Data Exchange (ETDEWEB)

Schrire, D.; Oguma, R.; Malen, K.

1994-12-31

A BWR reactor core may experience thermal-hydraulic instability under certain operating conditions. Generally, the instability results in neutron flux (i e generated neutronic power) and coolant flow and pressure oscillations, which reach a maximum `limit cycle` amplitude. The cladding response to power transients has been studied using noise analysis. These results have been compared to results from code calculations using the fuel code TOODEE 2. From these results the risk for fuel rod failure due to pellet-clad mechanical interaction and possible failure due to stress corrosion cracking (PCI) has been estimated. It turns out that for the oscillation frequencies of interest (0,3-0,5 Hz) the fuel response amplitude reduction makes PCI-failure improbable. 17 refs.

Phylloplane bacteria increase the negative impact of food limitation on insect fitness

NARCIS (Netherlands)

Olson, Grant L.; Myers, Judith H.; Hemerik, Lia; Cory, Jenny S.

2017-01-01

1. When populations of herbivorous insects increase in density, they can alter the quantity or quality of their food. The impacts of diet-related stressors on insect fitness have been investigated singly, but not simultaneously. 2. Foliage quantity and quality of red alder, Alnus rubra, were

Limit cycle behaviour of the bump-on-tail and ion-acoustic instability

International Nuclear Information System (INIS)

Janssen, P.A.E.M.; Rasmussen, J.J.

1980-12-01

The nonlinear dynamics of the bump-on-tail and current-driven ion-acoustic instability is considered. The eigenmodes have discrete k because of finite periodic boundary conditions. Increasing a critical parameter (the number density and the electron drift velocity respectively) above its neutral stable value by a small fractional amount Δ 2 , one mode becomes unstable. The nonlinear dynamics of the unstable mode is determined by means of the multiple time scale method. Usually, limit cycle behaviour is found. A short comparison with quasi-linear theory is given, and the results are compared with experiment. (Auth.)

Beam instability Workshop - plenary sessions

International Nuclear Information System (INIS)

2001-01-01

The purpose of this workshop was to provide a review of the mechanisms of limiting beam instabilities, their cures, including feedback, and beam measurement for synchrotron radiation light sources. 12 plenary sessions took place whose titles are: 1) challenging brilliance and lifetime issues with increasing currents; 2) limiting instabilities in multibunch; 3) experience from high currents in B factories; 4) longitudinal dynamics in high intensity/bunch; 5) Transverse instabilities for high intensity/bunch; 6) working group introduction from ESRF experience; 7) impedance modelling: simulations, minimization; 8) report on the broadband impedance measurements and modelling workshop; 9) feedback systems for synchrotron light sources; 10) beam instabilities diagnostics; 11) harmonic cavities: the pros and cons; and 12) experimental study of fast beam-ion instabilities at PLS. This document gathers the 12 articles that were presented during these sessions

Beam instability Workshop - plenary sessions

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-07-01

The purpose of this workshop was to provide a review of the mechanisms of limiting beam instabilities, their cures, including feedback, and beam measurement for synchrotron radiation light sources. 12 plenary sessions took place whose titles are: 1) challenging brilliance and lifetime issues with increasing currents; 2) limiting instabilities in multibunch; 3) experience from high currents in B factories; 4) longitudinal dynamics in high intensity/bunch; 5) Transverse instabilities for high intensity/bunch; 6) working group introduction from ESRF experience; 7) impedance modelling: simulations, minimization; 8) report on the broadband impedance measurements and modelling workshop; 9) feedback systems for synchrotron light sources; 10) beam instabilities diagnostics; 11) harmonic cavities: the pros and cons; and 12) experimental study of fast beam-ion instabilities at PLS. This document gathers the 12 articles that were presented during these sessions.

Anaerobic metabolism at thermal extremes: a metabolomic test of the oxygen limitation hypothesis in an aquatic insect.

Science.gov (United States)

Verberk, W C E P; Sommer, U; Davidson, R L; Viant, M R

2013-10-01

Thermal limits in ectotherms may arise through a mismatch between supply and demand of oxygen. At higher temperatures, the ability of their cardiac and ventilatory activities to supply oxygen becomes insufficient to meet their elevated oxygen demand. Consequently, higher levels of oxygen in the environment are predicted to enhance tolerance of heat, whereas reductions in oxygen are expected to reduce thermal limits. Here, we extend previous research on thermal limits and oxygen limitation in aquatic insect larvae and directly test the hypothesis of increased anaerobic metabolism and lower energy status at thermal extremes. We quantified metabolite profiles in stonefly nymphs under varying temperatures and oxygen levels. Under normoxia, the concept of oxygen limitation applies to the insects studied. Shifts in the metabolome of heat-stressed stonefly nymphs clearly indicate the onset of anaerobic metabolism (e.g., accumulation of lactate, acetate, and alanine), a perturbation of the tricarboxylic acid cycle (e.g., accumulation of succinate and malate), and a decrease in energy status (e.g., ATP), with corresponding decreases in their ability to survive heat stress. These shifts were more pronounced under hypoxic conditions, and negated by hyperoxia, which also improved heat tolerance. Perturbations of metabolic pathways in response to either heat stress or hypoxia were found to be somewhat similar but not identical. Under hypoxia, energy status was greatly compromised at thermal extremes, but energy shortage and anaerobic metabolism could not be conclusively identified as the sole cause underlying thermal limits under hyperoxia. Metabolomics proved useful for suggesting a range of possible mechanisms to explore in future investigations, such as the involvement of leaking membranes or free radicals. In doing so, metabolomics provided a more complete picture of changes in metabolism under hypoxia and heat stress.

Edible insects are the future?

Science.gov (United States)

van Huis, Arnold

2016-08-01

The global increase in demand for meat and the limited land area available prompt the search for alternative protein sources. Also the sustainability of meat production has been questioned. Edible insects as an alternative protein source for human food and animal feed are interesting in terms of low greenhouse gas emissions, high feed conversion efficiency, low land use, and their ability to transform low value organic side streams into high value protein products. More than 2000 insect species are eaten mainly in tropical regions. The role of edible insects in the livelihoods and nutrition of people in tropical countries is discussed, but this food source is threatened. In the Western world, there is an increasing interest in edible insects, and examples are given. Insects as feed, in particular as aquafeed, have a large potential. Edible insects have about the same protein content as conventional meat and more PUFA. They may also have some beneficial health effects. Edible insects need to be processed and turned into palatable dishes. Food safety may be affected by toxicity of insects, contamination with pathogens, spoilage during conservation and allergies. Consumer attitude is a major issue in the Western world and a number of strategies are proposed to encourage insect consumption. We discuss research pathways to make insects a viable sector in food and agriculture: an appropriate disciplinary focus, quantifying its importance, comparing its nutritional value to conventional protein sources, environmental benefits, safeguarding food safety, optimising farming, consumer acceptance and gastronomy.

Ecological turmoil in evolutionary dynamics of plant-insect interactions: defense to offence.

Science.gov (United States)

Mishra, Manasi; Lomate, Purushottam R; Joshi, Rakesh S; Punekar, Sachin A; Gupta, Vidya S; Giri, Ashok P

2015-10-01

Available history manifests contemporary diversity that exists in plant-insect interactions. A radical thinking is necessary for developing strategies that can co-opt natural insect-plant mutualism, ecology and environmental safety for crop protection since current agricultural practices can reduce species richness and evenness. The global environmental changes, such as increased temperature, CO₂ and ozone levels, biological invasions, land-use change and habitat fragmentation together play a significant role in re-shaping the plant-insect multi-trophic interactions. Diverse natural products need to be studied and explored for their biological functions as insect pest control agents. In order to assure the success of an integrated pest management strategy, human activities need to be harmonized to minimize the global climate changes. Plant-insect interaction is one of the most primitive and co-evolved associations, often influenced by surrounding changes. In this review, we account the persistence and evolution of plant-insect interactions, with particular focus on the effect of climate change and human interference on these interactions. Plants and insects have been maintaining their existence through a mutual service-resource relationship while defending themselves. We provide a comprehensive catalog of various defense strategies employed by the plants and/or insects. Furthermore, several important factors such as accelerated diversification, imbalance in the mutualism, and chemical arms race between plants and insects as indirect consequences of human practices are highlighted. Inappropriate implementation of several modern agricultural practices has resulted in (i) endangered mutualisms, (ii) pest status and resistance in insects and (iii) ecological instability. Moreover, altered environmental conditions eventually triggered the resetting of plant-insect interactions. Hence, multitrophic approaches that can harmonize human activities and minimize their

Elastic instability model of rapid beak closure in hummingbirds.

Science.gov (United States)

Smith, M L; Yanega, G M; Ruina, A

2011-08-07

The hummingbird beak, specialized for feeding on floral nectars, is also uniquely adapted to eating flying insects. During insect capture the beak often appears to close at a rate that cannot be explained by direct muscular action alone. Here we show that the lower jaw of hummingbirds has a shape and compliance that allows for a controlled elastic snap. Furthermore, hummingbirds have the musculature needed to independently bend and twist the sides of the lower jaw. According to both our simple physical model and our elastic instability calculation, the jaw can be smoothly opened and then snapped closed through an appropriate sequence of bending and twisting actions by the muscles of the lower jaw. Copyright © 2011 Elsevier Ltd. All rights reserved.

APC/C Dysfunction Limits Excessive Cancer Chromosomal Instability.

Science.gov (United States)

Sansregret, Laurent; Patterson, James O; Dewhurst, Sally; López-García, Carlos; Koch, André; McGranahan, Nicholas; Chao, William Chong Hang; Barry, David J; Rowan, Andrew; Instrell, Rachael; Horswell, Stuart; Way, Michael; Howell, Michael; Singleton, Martin R; Medema, René H; Nurse, Paul; Petronczki, Mark; Swanton, Charles

2017-02-01

Intercellular heterogeneity, exacerbated by chromosomal instability (CIN), fosters tumor heterogeneity and drug resistance. However, extreme CIN correlates with improved cancer outcome, suggesting that karyotypic diversity required to adapt to selection pressures might be balanced in tumors against the risk of excessive instability. Here, we used a functional genomics screen, genome editing, and pharmacologic approaches to identify CIN-survival factors in diploid cells. We find partial anaphase-promoting complex/cyclosome (APC/C) dysfunction lengthens mitosis, suppresses pharmacologically induced chromosome segregation errors, and reduces naturally occurring lagging chromosomes in cancer cell lines or following tetraploidization. APC/C impairment caused adaptation to MPS1 inhibitors, revealing a likely resistance mechanism to therapies targeting the spindle assembly checkpoint. Finally, CRISPR-mediated introduction of cancer somatic mutations in the APC/C subunit cancer driver gene CDC27 reduces chromosome segregation errors, whereas reversal of an APC/C subunit nonsense mutation increases CIN. Subtle variations in mitotic duration, determined by APC/C activity, influence the extent of CIN, allowing cancer cells to dynamically optimize fitness during tumor evolution. We report a mechanism whereby cancers balance the evolutionary advantages associated with CIN against the fitness costs caused by excessive genome instability, providing insight into the consequence of CDC27 APC/C subunit driver mutations in cancer. Lengthening of mitosis through APC/C modulation may be a common mechanism of resistance to cancer therapeutics that increase chromosome segregation errors. Cancer Discov; 7(2); 218-33. ©2017 AACR.See related commentary by Burkard and Weaver, p. 134This article is highlighted in the In This Issue feature, p. 115. ©2017 American Association for Cancer Research.

Effects of visual feedback balance training on the balance and ankle instability in adult men with functional ankle instability.

Science.gov (United States)

Nam, Seung-Min; Kim, Kyoung; Lee, Do Youn

2018-01-01

[Purpose] This study examined the effects of visual feedback balance training on the balance and ankle instability in adult men with functional ankle instability. [Subjects and Methods] Twenty eight adults with functional ankle instability, divided randomly into an experimental group, which performed visual feedback balance training for 20 minutes and ankle joint exercises for 10 minutes, and a control group, which performed ankle joint exercise for 30 minutes. Exercises were completed three times a week for 8 weeks. Bio rescue was used for balance ability. It measured limit of stability at one minute. For ankle instability was measured using Cumberland ankle instability tool (CAIT). This measure was performed before and after the experiments in each group. [Results] The experimental group had significant increase in the Limit of Stability and CAIT score. The control group had significant increase in CAIT score. While the Limit of Stability increased without significance. [Conclusion] In conclusion, visual feedback balance training can be recommended as a treatment method for patients with functional ankle instability.

Triclade: influence of a sinuous secondary instability on the Richtmyer-Meshkov instabilities

International Nuclear Information System (INIS)

Boulet, M.; Griffond, J.

2004-01-01

Occurrence of a secondary instability developing after the Richtmyer-Meshkov (primary) instability is emphasized thanks to numerical simulations with the TRICLADE code. We are mainly considering 2D perturbations describes by trigonometric function cosine or [cosine]. However, the 3D case is also tackled. The sinuous secondary instability is characterized by the loss of the symmetries in the direction normal to the interface at its crests. It reduces the late time growing rate of the 'mushrooms' formed by the Richtmyer-Meshkov instability. Related simplified problems, like symmetrical Riemann problems or the Mallier-Maslowe array of counter-rotating vortices, allow us to perform 2D linear stability analysis. Thus, we show that the sinuous secondary instability is not a numerical artifact and that is comes from the continuous incompressible velocity field in the interface region. This instability implies temporal limitations for the validity of single mode simulations; therefore multimode simulations are necessary to study the ]ate-time behaviour of interfaces bitted by shocks. (authors)

Relativistic gravitational instabilities

International Nuclear Information System (INIS)

Schutz, B.F.

1987-01-01

The purpose of these lectures is to review and explain what is known about the stability of relativistic stars and black holes, with particular emphases on two instabilities which are due entirely to relativistic effects. The first of these is the post-Newtonian pulsational instability discovered independently by Chandrasekhar (1964) and Fowler (1964). This effectively ruled out the then-popular supermassive star model for quasars, and it sets a limit to the central density of white dwarfs. The second instability was also discovered by Chandrasekhar (1970): the gravitational wave induced instability. This sets an upper bound on the rotation rate of neutron stars, which is near that of the millisecond pulsar PSR 1937+214, and which is beginning to constrain the equation of state of neutron matter. 111 references, 5 figures

Effects of nitrogen fertilization on forest trees in relation to insect resistance and to red-listed insect species

International Nuclear Information System (INIS)

Glynn, C.; Herms, D.A.

2001-10-01

Ecosystems worldwide are experiencing unprecedented nitrogen enrichment through fertilization and pollution. While longterm ecological consequences are difficult to predict, it seems that plants and animals adapted to nitrogen-limited environments are at particular risk from these changes. This report summarizes the limited body of literature which addresses this important topic. From a herbivoreAes perspective, fertilization increases the nutritional quality of host plant tissues. In some cases fertilization has lead to decreased production of defensive compounds. How this affects populations of insects is unclear because fertilization affects not only herbivores but their natural enemies. This report outlines how fertilization affects tree processes such as growth, photosynthesis, and production of defensive compounds. The many factors that affect insect repsonse to fertilization and the difficulties in assessing how fertilization affects insect populations are discussed

Does fragmentation of Urtica habitats affect phytophagous and predatory insects differentially?

Science.gov (United States)

Zabel, Jörg; Tscharntke, Teja

1998-09-01

Effects of habitat fragmentation on the insect community of stinging nettle (Urtica dioica L.) were studied, using 32 natural nettle patches of different area and degree of isolation in an agricultural landscape. Habitat fragmentation reduced the species richness of Heteroptera, Auchenorrhyncha, and Coleoptera, and the abundance of populations. Habitat isolation and area reduction did not affect all insect species equally. Monophagous herbivores had a higher probability of absence from small patches than all (monophagous and polyphagous) herbivore species, and the percentage of monophagous herbivores increased with habitat area. Abundance and population variability of species were negatively correlated and could both be used as a predictor of the percentage of occupied habitats. Species richness of herbivores correlated (positively) with habitat area, while species richness of predators correlated (negatively) with habitat isolation. In logistic regressions, the probability of absence of monophagous herbivores from habitat patches could only be explained by habitat area (in 4 out of 10 species) and predator absence probability only by habitat isolation (in 3 out of 14 species). Presumably because of the instability of higher-trophic-level populations and dispersal limitation, predators were more affected by habitat isolation than herbivores, while they did not differ from herbivore populations with respect to abundance or variability. Thus increasing habitat connectivity in the agricultural landscape should primarily promote predator populations.

Collisional effect on the Weibel instability in the limit of high plasma ...

Indian Academy of Sciences (India)

Davidson and Hammer [12] studied the wave instabilities which included transverse electromagnetic WI driven by kinetic energy anisotropy in an unmag- netized plasma (e.g., electromagnetic instabilities driven by thermal anisotropy or directed counter-streaming motion). Zaki [13] studied the excitation of electromagnetic ...

Edible insects are the future?

OpenAIRE

Huis, van, Arnold

2016-01-01

The global increase in demand for meat and the limited land area available prompt the search for alternative protein sources. Also the sustainability of meat production has been questioned. Edible insects as an alternative protein source for human food and animal feed are interesting in terms of low greenhouse gas emissions, high feed conversion efficiency, low land use, and their ability to transform low value organic side streams into high value protein products. More than 2000 insect speci...

Steering soil microbiomes to suppress aboveground insect pests

NARCIS (Netherlands)

Pineda, Ana; Kaplan, Ian; Bezemer, T. Martijn

2017-01-01

Soil-borne microbes affect aboveground herbivorous insects through a cascade of molecular and chemical changes in the plant, but knowledge of these microbe?plant?insect interactions is mostly limited to one or a few microbial strains. Yet, the soil microbial community comprises thousands of unique

Insect herbivory and vertebrate grazing impact food limitation and grasshopper populations during a severe outbreak

Science.gov (United States)

Interspecific competition between distantly related herbivores, as well as between large vertebrate herbivores and phytophagous insects, has received little attention. Livestock grazing is the dominant land use in western North American grasslands, where phytophagous insects can be the dominant herb...

Insect Consumption to Address Undernutrition, a National Survey on the Prevalence of Insect Consumption among Adults and Vendors in Laos.

Science.gov (United States)

Barennes, Hubert; Phimmasane, Maniphet; Rajaonarivo, Christian

2015-01-01

Insect consumption (entomophagy) is a potentially high nutritious and healthy source of food with high fat, protein, vitamin, fiber and micronutrient content. At least 2 billion people globally eat insects (over 1900 edible species) though this habit is regarded negatively by others. There is a limited amount of data on the perception and consumption of insects. We conducted a national cross-sectional survey in the Lao People's Democratic Republic (Laos) to assess the prevalence and characteristics of insect consumption among adult lay people and insect vendors. We conducted a multi stage randomized national survey in 1303 households in 96 villages in 16 Lao provinces. Three insect vendors or collectors per village were also included. A standardized pretested questionnaire addressed the following issues: socioeconomic characteristics, type of insects consumed and frequency of consumption, reasons and trends in consumption as well as reports on side effects, over the last 10 years. A total of 1059 adults (Sex ratio F/M: 1.2, 30 ethnic groups), and 256 vendors were enrolled. A total of 1025 (96.8%) lay people were currently insect consumers, 135 (13.0%) daily or weekly consumers, and 322 (31.1%) consumed several times per month. For the majority (575, 55.6%) the consumption was infrequent (less than a few times per year) and only 22 (2%) had never eaten insects. Consumption started in childhood. Insect availability was seasonal (670, 63.2%) and respondents would have eaten more insects, if they had been more available (919, 86.7%). Hmong and Leu ethnic groups had significantly lower consumption levels than the general population. Eggs of weaver ants, short-tailed crickets, crickets, grasshoppers, and cicadas were the top 5 insects consumed. Consumption had decreased in the last decade, mostly due to less availability (869; 84.0%) and change of life (29; 5.5%). Of 1059, 80 (7.5%) reported allergy problems and 106 (10.0%) reported some use in traditional medicine. A

Insect Consumption to Address Undernutrition, a National Survey on the Prevalence of Insect Consumption among Adults and Vendors in Laos.

Directory of Open Access Journals (Sweden)

Hubert Barennes

Full Text Available Insect consumption (entomophagy is a potentially high nutritious and healthy source of food with high fat, protein, vitamin, fiber and micronutrient content. At least 2 billion people globally eat insects (over 1900 edible species though this habit is regarded negatively by others. There is a limited amount of data on the perception and consumption of insects. We conducted a national cross-sectional survey in the Lao People's Democratic Republic (Laos to assess the prevalence and characteristics of insect consumption among adult lay people and insect vendors.We conducted a multi stage randomized national survey in 1303 households in 96 villages in 16 Lao provinces. Three insect vendors or collectors per village were also included. A standardized pretested questionnaire addressed the following issues: socioeconomic characteristics, type of insects consumed and frequency of consumption, reasons and trends in consumption as well as reports on side effects, over the last 10 years.A total of 1059 adults (Sex ratio F/M: 1.2, 30 ethnic groups, and 256 vendors were enrolled. A total of 1025 (96.8% lay people were currently insect consumers, 135 (13.0% daily or weekly consumers, and 322 (31.1% consumed several times per month. For the majority (575, 55.6% the consumption was infrequent (less than a few times per year and only 22 (2% had never eaten insects. Consumption started in childhood. Insect availability was seasonal (670, 63.2% and respondents would have eaten more insects, if they had been more available (919, 86.7%. Hmong and Leu ethnic groups had significantly lower consumption levels than the general population. Eggs of weaver ants, short-tailed crickets, crickets, grasshoppers, and cicadas were the top 5 insects consumed. Consumption had decreased in the last decade, mostly due to less availability (869; 84.0% and change of life (29; 5.5%. Of 1059, 80 (7.5% reported allergy problems and 106 (10.0% reported some use in traditional medicine. A

Extracellular ice phase transitions in insects.

Science.gov (United States)

Hawes, T C

2014-01-01

At temperatures below their temperature of crystallization (Tc), the extracellular body fluids of insects undergo a phase transition from liquid to solid. Insects that survive the transition to equilibrium (complete freezing of the body fluids) are designated as freeze tolerant. Although this phenomenon has been reported and described in many Insecta, current nomenclature and theory does not clearly delineate between the process of transition (freezing) and the final solid phase itself (the frozen state). Thus freeze tolerant insects are currently, by convention, described in terms of the temperature at which the crystallization of their body fluids is initiated, Tc. In fact, the correct descriptor for insects that tolerate freezing is the temperature of equilibrium freezing, Tef. The process of freezing is itself a separate physical event with unique physiological stresses that are associated with ice growth. Correspondingly there are a number of insects whose physiological cryo-limits are very specifically delineated by this transitional envelope. The distinction also has considerable significance for our understanding of insect cryobiology: firstly, because the ability to manage endogenous ice growth is a fundamental segregator of cryotype; and secondly, because our understanding of internal ice management is still largely nascent.

Context dependency and generality of fever in insects

Science.gov (United States)

Stahlschmidt, Z. R.; Adamo, S. A.

2013-07-01

Fever can reduce mortality in infected animals. Yet, despite its fitness-enhancing qualities, fever often varies among animals. We used several approaches to examine this variation in insects. Texas field crickets ( Gryllus texensis) exhibited a modest fever (1 °C increase in preferred body temperature, T pref) after injection of prostaglandin, which putatively mediates fever in both vertebrates and invertebrates, but they did not exhibit fever during chronic exposure to heat-killed bacteria. Further, chronic food limitation and mating status did not affect T pref or the expression of behavioural fever, suggesting limited context dependency of fever in G. texensis. Our meta-analysis of behavioural fever studies indicated that behavioural fever occurs in many insects, but it is not ubiquitous. Thus, both empirical and meta-analytical results suggest that the fever response in insects `is widespread, although certainly not inevitable' (Moore 2002). We highlight the need for future work focusing on standardizing an experimental protocol to measure behavioural fever, understanding the specific mechanism(s) underlying fever in insects, and examining whether ecological or physiological costs often outweigh the benefits of fever and can explain the sporadic nature of fever in insects.

Limit Cycle Behaviour of the Bump-on-Tail Instability

DEFF Research Database (Denmark)

Janssen, P. A. E. M.; Juul Rasmussen, Jens

1981-01-01

The nonlinear dynamics of the bump‐on‐tail instability is considered. The eigenmodes have discrete k because of finite periodic boundary conditions. Increasing a critical parameter (the number density) above its neutral stable value by a small fractional amount Δ2, one mode becomes unstable...

A lightweight, inexpensive robotic system for insect vision.

Science.gov (United States)

Sabo, Chelsea; Chisholm, Robert; Petterson, Adam; Cope, Alex

2017-09-01

Designing hardware for miniaturized robotics which mimics the capabilities of flying insects is of interest, because they share similar constraints (i.e. small size, low weight, and low energy consumption). Research in this area aims to enable robots with similarly efficient flight and cognitive abilities. Visual processing is important to flying insects' impressive flight capabilities, but currently, embodiment of insect-like visual systems is limited by the hardware systems available. Suitable hardware is either prohibitively expensive, difficult to reproduce, cannot accurately simulate insect vision characteristics, and/or is too heavy for small robotic platforms. These limitations hamper the development of platforms for embodiment which in turn hampers the progress on understanding of how biological systems fundamentally work. To address this gap, this paper proposes an inexpensive, lightweight robotic system for modelling insect vision. The system is mounted and tested on a robotic platform for mobile applications, and then the camera and insect vision models are evaluated. We analyse the potential of the system for use in embodiment of higher-level visual processes (i.e. motion detection) and also for development of navigation based on vision for robotics in general. Optic flow from sample camera data is calculated and compared to a perfect, simulated bee world showing an excellent resemblance. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Edible insects in China: Utilization and prospects.

Science.gov (United States)

Feng, Ying; Chen, Xiao-Ming; Zhao, Min; He, Zhao; Sun, Long; Wang, Cheng-Ye; Ding, Wei-Feng

2018-04-01

The use of edible insects has a long history in China, where they have been consumed for more than 2000 years. In general, the level of acceptance is high for the consumption of insects in China. Many studies on edible insects have been conducted in the last 20 years, and the scope of the research includes the culture of entomophagy and the identification, nutritional value, farming and breeding of edible insects, in addition to food production and safety. Currently, 324 species of insects from 11 orders are documented that are either edible or associated with entomophagy in China, which include the common edible species, some less commonly consumed species and some medicinal insects. However, only approximately 10 to 20 types of insects are regularly consumed. The nutritional values for 174 species are available in China, including edible, feed and medicinal species. Although the nutritional values vary among species, all the insects examined contain protein, fat, vitamins and minerals at levels that meet human nutritional requirements. Edible insects were, and continue to be, consumed by different ethnic groups in many parts of China. People directly consume insects or food products made from insects. The processing of products from insect protein powder, oil and chitin, and the development of healthcare foods has been studied in China. People also consume insects indirectly by eating livestock that were fed insects, which may be a more acceptable pathway to use insects in human diets. Although limited, the data on the food safety of insects indicate that insects are safe for food or feed. Incidences of allergic reactions after consuming silkworm pupae, cicadas and crickets have been reported in China. Insect farming is a unique breeding industry in rural China and is a source of income for local people. Insects are reared and bred for human food, medicine and animal feed using two approaches in China: the insects are either fully domesticated and reared

New feed ingredients: the insect opportunity.

Science.gov (United States)

van Raamsdonk, L W D; van der Fels-Klerx, H J; de Jong, J

2017-08-01

In the framework of sustainability and a circular economy, new ingredients for feed are desired and, to this end, initiatives for implementing such novel ingredients have been started. The initiatives include a range of different sources, of which insects are of particular interest. Within the European Union, generally, a new feed ingredient should comply with legal constraints in terms of 'yes, provided that' its safety commits to a range of legal limits for heavy metals, mycotoxins, pesticides, contaminants, pathogens etc. In the case of animal proteins, however, a second legal framework applies which is based on the principle 'no, unless'. This legislation for eradicating transmissible spongiform encephalopathy consists of prohibitions with a set of derogations applying to specific situations. Insects are currently considered animal proteins. The use of insect proteins is a good case to illustrate this difference between a positive, although restricted, modus and a negative modus for allowing animal proteins. This overview presents aspects in the areas of legislation, feed safety, environmental issues, efficiency and detection of the identity of insects. Use of insects as an extra step in the feed production chain costs extra energy and this results in a higher footprint. A measure for energy conversion should be used to facilitate the comparison between production systems based on cold- versus warm-blooded animals. Added value can be found by applying new commodities for rearing, including but not limited to category 2 animal by-products, catering and household waste including meat, and manure. Furthermore, monitoring of a correct use of insects is one possible approach for label control, traceability and prevention of fraud. The link between legislation and enforcement is strong. A principle called WISE (Witful, Indicative, Societal demands, Enforceable) is launched for governing the relationship between the above-mentioned aspects.

Streaming gravity mode instability

International Nuclear Information System (INIS)

Wang Shui.

1989-05-01

In this paper, we study the stability of a current sheet with a sheared flow in a gravitational field which is perpendicular to the magnetic field and plasma flow. This mixing mode caused by a combined role of the sheared flow and gravity is named the streaming gravity mode instability. The conditions of this mode instability are discussed for an ideal four-layer model in the incompressible limit. (author). 5 refs

Respiratory symptoms in insect breeders.

Science.gov (United States)

Harris-Roberts, J; Fishwick, D; Tate, P; Rawbone, R; Stagg, S; Barber, C M; Adisesh, A

2011-08-01

A number of specialist food suppliers in the UK breed and distribute insects and insect larvae as food for exotic pets, such as reptiles, amphibians and invertebrates. To investigate the extent of work-related (WR) symptoms and workplace-specific serum IgE in workers potentially exposed to a variety of biological contaminants, including insect and insect larvae allergens, endotoxin and cereal allergens at a UK specialist insect breeding facility. We undertook a study of respiratory symptoms and exposures at the facility, with subsequent detailed clinical assessment of one worker. All 32 workers were assessed clinically using a respiratory questionnaire and lung function. Eighteen workers consented to provide serum for determination of specific IgE to workplace allergens. Thirty-four per cent (11/32) of insect workers reported WR respiratory symptoms. Sensitization, as judged by specific IgE, was found in 29% (4/14) of currently exposed workers. Total inhalable dust levels ranged from 1.2 to 17.9 mg/m(3) [mean 4.3 mg/m(3) (SD 4.4 mg/m(3)), median 2.0 mg/m(3)] and endotoxin levels of up to 29435 EU/m(3) were recorded. Exposure to organic dusts below the levels for which there are UK workplace exposure limits can result in respiratory symptoms and sensitization. The results should alert those responsible for the health of similarly exposed workers to the potential for respiratory ill-health and the need to provide a suitable health surveillance programme.

Microbial brokers of insect-plant interactions revisited.

Science.gov (United States)

Douglas, Angela E

2013-07-01

Recent advances in sequencing methods have transformed the field of microbial ecology, making it possible to determine the composition and functional capabilities of uncultured microorganisms. These technologies have been instrumental in the recognition that resident microorganisms can have profound effects on the phenotype and fitness of their animal hosts by modulating the animal signaling networks that regulate growth, development, behavior, etc. Against this backdrop, this review assesses the impact of microorganisms on insect-plant interactions, in the context of the hypothesis that microorganisms are biochemical brokers of plant utilization by insects. There is now overwhelming evidence for a microbial role in insect utilization of certain plant diets with an extremely low or unbalanced nutrient content. Specifically, microorganisms enable insect utilization of plant sap by synthesizing essential amino acids. They also can broker insect utilization of plant products of extremely high lignocellulose content, by enzymatic breakdown of complex plant polysaccharides, nitrogen fixation, and sterol synthesis. However, the experimental evidence for microbial-mediated detoxification of plant allelochemicals is limited. The significance of microorganisms as brokers of plant utilization by insects is predicted to vary, possibly widely, as a result of potentially complex interactions between the composition of the microbiota and the diet and insect developmental age or genotype. For every insect species feeding on plant material, the role of resident microbiota as biochemical brokers of plant utilization is a testable hypothesis.

Observation of Parametric Instability in Advanced LIGO.

Science.gov (United States)

Evans, Matthew; Gras, Slawek; Fritschel, Peter; Miller, John; Barsotti, Lisa; Martynov, Denis; Brooks, Aidan; Coyne, Dennis; Abbott, Rich; Adhikari, Rana X; Arai, Koji; Bork, Rolf; Kells, Bill; Rollins, Jameson; Smith-Lefebvre, Nicolas; Vajente, Gabriele; Yamamoto, Hiroaki; Adams, Carl; Aston, Stuart; Betzweiser, Joseph; Frolov, Valera; Mullavey, Adam; Pele, Arnaud; Romie, Janeen; Thomas, Michael; Thorne, Keith; Dwyer, Sheila; Izumi, Kiwamu; Kawabe, Keita; Sigg, Daniel; Derosa, Ryan; Effler, Anamaria; Kokeyama, Keiko; Ballmer, Stefan; Massinger, Thomas J; Staley, Alexa; Heinze, Matthew; Mueller, Chris; Grote, Hartmut; Ward, Robert; King, Eleanor; Blair, David; Ju, Li; Zhao, Chunnong

2015-04-24

Parametric instabilities have long been studied as a potentially limiting effect in high-power interferometric gravitational wave detectors. Until now, however, these instabilities have never been observed in a kilometer-scale interferometer. In this Letter, we describe the first observation of parametric instability in a gravitational wave detector, and the means by which it has been removed as a barrier to progress.

Phytoplasmas: bacteria that manipulate plants and insects.

Science.gov (United States)

Hogenhout, Saskia A; Oshima, Kenro; Ammar, El-Desouky; Kakizawa, Shigeyuki; Kingdom, Heather N; Namba, Shigetou

2008-07-01

Superkingdom Prokaryota; Kingdom Monera; Domain Bacteria; Phylum Firmicutes (low-G+C, Gram-positive eubacteria); Class Mollicutes; Candidatus (Ca.) genus Phytoplasma. Ca. Phytoplasma comprises approximately 30 distinct clades based on 16S rRNA gene sequence analyses of approximately 200 phytoplasmas. Phytoplasmas are mostly dependent on insect transmission for their spread and survival. The phytoplasma life cycle involves replication in insects and plants. They infect the insect but are phloem-limited in plants. Members of Ca. Phytoplasma asteris (16SrI group phytoplasmas) are found in 80 monocot and dicot plant species in most parts of the world. Experimentally, they can be transmitted by approximately 30, frequently polyphagous insect species, to 200 diverse plant species. In plants, phytoplasmas induce symptoms that suggest interference with plant development. Typical symptoms include: witches' broom (clustering of branches) of developing tissues; phyllody (retrograde metamorphosis of the floral organs to the condition of leaves); virescence (green coloration of non-green flower parts); bolting (growth of elongated stalks); formation of bunchy fibrous secondary roots; reddening of leaves and stems; generalized yellowing, decline and stunting of plants; and phloem necrosis. Phytoplasmas can be pathogenic to some insect hosts, but generally do not negatively affect the fitness of their major insect vector(s). In fact, phytoplasmas can increase fecundity and survival of insect vectors, and may influence flight behaviour and plant host preference of their insect hosts. The most common practices are the spraying of various insecticides to control insect vectors, and removal of symptomatic plants. Phytoplasma-resistant cultivars are not available for the vast majority of affected crops.

Insect Cell Culture

NARCIS (Netherlands)

Oers, van M.M.; Lynn, D.E.

2010-01-01

Insect cell cultures are widely used in studies on insect cell physiology, developmental biology and microbial pathology. In particular, insect cell culture is an indispensable tool for the study of insect viruses. The first continuously growing insect cell cultures were established from

Sterile insect technique and radiation in insect control

International Nuclear Information System (INIS)

1982-01-01

Out of 39 papers and 6 summaries of the poster presentations published in this proceeding series, 23 respectively fall within the INIS subject scope. Four main topics were covered: a review of the sterile insect technique against various insect pests; its application to tsetse flies in eradication programmes; quality control of mass-reared insects for release; and the development of genetic approaches to insect mass rearing and control. Other topics emphasized integrated pest management, computer models and radioisotope labelling

Investigating Engineered Ribonucleoprotein Particles to Improve Oral RNAi Delivery in Crop Insect Pests.

Science.gov (United States)

Gillet, François-Xavier; Garcia, Rayssa A; Macedo, Leonardo L P; Albuquerque, Erika V S; Silva, Maria C M; Grossi-de-Sa, Maria F

2017-01-01

Genetically modified (GM) crops producing double-stranded RNAs (dsRNAs) are being investigated largely as an RNA interference (RNAi)-based resistance strategy against crop insect pests. However, limitations of this strategy include the sensitivity of dsRNA to insect gut nucleases and its poor insect cell membrane penetration. Working with the insect pest cotton boll weevil ( Anthonomus grandis ), we showed that the chimeric protein PTD-DRBD (peptide transduction domain-dsRNA binding domain) combined with dsRNA forms a ribonucleoprotein particle (RNP) that improves the effectiveness of the RNAi mechanism in the insect. The RNP slows down nuclease activity, probably by masking the dsRNA. Furthermore, PTD-mediated internalization in insect gut cells is achieved within minutes after plasma membrane contact, limiting the exposure time of the RNPs to gut nucleases. Therefore, the RNP provides an approximately 2-fold increase in the efficiency of insect gene silencing upon oral delivery when compared to naked dsRNA. Taken together, these data demonstrate the role of engineered RNPs in improving dsRNA stability and cellular entry, representing a path toward the design of enhanced RNAi strategies in GM plants against crop insect pests.

Investigating Engineered Ribonucleoprotein Particles to Improve Oral RNAi Delivery in Crop Insect Pests

Directory of Open Access Journals (Sweden)

François-Xavier Gillet

2017-04-01

Full Text Available Genetically modified (GM crops producing double-stranded RNAs (dsRNAs are being investigated largely as an RNA interference (RNAi-based resistance strategy against crop insect pests. However, limitations of this strategy include the sensitivity of dsRNA to insect gut nucleases and its poor insect cell membrane penetration. Working with the insect pest cotton boll weevil (Anthonomus grandis, we showed that the chimeric protein PTD-DRBD (peptide transduction domain—dsRNA binding domain combined with dsRNA forms a ribonucleoprotein particle (RNP that improves the effectiveness of the RNAi mechanism in the insect. The RNP slows down nuclease activity, probably by masking the dsRNA. Furthermore, PTD-mediated internalization in insect gut cells is achieved within minutes after plasma membrane contact, limiting the exposure time of the RNPs to gut nucleases. Therefore, the RNP provides an approximately 2-fold increase in the efficiency of insect gene silencing upon oral delivery when compared to naked dsRNA. Taken together, these data demonstrate the role of engineered RNPs in improving dsRNA stability and cellular entry, representing a path toward the design of enhanced RNAi strategies in GM plants against crop insect pests.

Insect biofuel cells using trehalose included in insect hemolymph leading to an insect-mountable biofuel cell.

Science.gov (United States)

Shoji, Kan; Akiyama, Yoshitake; Suzuki, Masato; Hoshino, Takayuki; Nakamura, Nobuhumi; Ohno, Hiroyuki; Morishima, Keisuke

2012-12-01

In this paper, an insect biofuel cell (BFC) using trehalose included in insect hemolymph was developed. The insect BFC is based on trehalase and glucose oxidase (GOD) reaction systems which oxidize β-glucose obtained by hydrolyzing trehalose. First, we confirmed by LC-MS that a sufficient amount of trehalose was present in the cockroach hemolymph (CHL). The maximum power density obtained using the insect BFC was 6.07 μW/cm(2). The power output was kept more than 10 % for 2.5 h by protecting the electrodes with a dialysis membrane. Furthermore, the maximum power density was increased to 10.5 μW/cm(2) by using an air diffusion cathode. Finally, we succeeded in driving a melody integrated circuit (IC) and a piezo speaker by connecting five insect BFCs in series. The results indicate that the insect BFC is a promising insect-mountable battery to power environmental monitoring micro-tools.

Notes from the ‘Insects in a gastronomic context’ workshop in Bangkok, Thailand

DEFF Research Database (Denmark)

Halloran, Afton Marina Szasz; Flore, Roberto; Mercier, C.

2015-01-01

Amidst the growing interest in edible insects, most insect dishes featured on menus or during public events are still primarily focused on fried, freeze dried or pulverised insects. This can be attributed to a limited understanding and knowledge of the complexity and variation in unique sensory p...

Stinging insect allergy: state of the art 2015.

Science.gov (United States)

Tankersley, Michael S; Ledford, Dennis K

2015-01-01

Stinging insect allergy is responsible for more than 10% of all cases of anaphylaxis. The potential culprit insects are diverse and vary with geography. The incidence of insect allergy is declining in some areas and increasing in others, possibly due to effects of climate change, introduction of species into new areas, outdoor recreational activities, and movement of human populations that brings insects into contact with a greater number of people. Flying Hymenoptera and imported fire ant stings are responsible for the majority of patients evaluated for insect anaphylaxis. The most efficient means of identifying allergy to insects is skin testing although falsely positive and negative results occur. The limitations of testing coupled with the natural temporal variability of allergic sensitivity complicate the interpretation of test results. The clinical history is of paramount importance to be certain that the test results are relevant; therefore, screening or testing before a history of a sting reaction is not advisable. Mast cell disorders are associated with severe anaphylaxis from insect stings and should be considered in affected subjects. Insect immunotherapy, using venoms for most insects and whole-body extracts for imported fire ants, is proven effective in reducing the likelihood of anaphylaxis due to subsequent stings from 40%-60% to less than 5%. Future clinical application of component testing or in vitro cellular tests, such as the basophil activation test, may improve optimal choices for immunotherapy. Published by Elsevier Inc.

Acoustic communication in insect disease vectors

Directory of Open Access Journals (Sweden)

Felipe de Mello Vigoder

2013-01-01

Full Text Available Acoustic signalling has been extensively studied in insect species, which has led to a better understanding of sexual communication, sexual selection and modes of speciation. The significance of acoustic signals for a blood-sucking insect was first reported in the XIX century by Christopher Johnston, studying the hearing organs of mosquitoes, but has received relatively little attention in other disease vectors until recently. Acoustic signals are often associated with mating behaviour and sexual selection and changes in signalling can lead to rapid evolutionary divergence and may ultimately contribute to the process of speciation. Songs can also have implications for the success of novel methods of disease control such as determining the mating competitiveness of modified insects used for mass-release control programs. Species-specific sound “signatures” may help identify incipient species within species complexes that may be of epidemiological significance, e.g. of higher vectorial capacity, thereby enabling the application of more focussed control measures to optimise the reduction of pathogen transmission. Although the study of acoustic communication in insect vectors has been relatively limited, this review of research demonstrates their value as models for understanding both the functional and evolutionary significance of acoustic communication in insects.

Beneficial Insects and Insect Pollinators on Milkweed in South Georgia

Science.gov (United States)

Insect pollinators are essential for the reproduction of more than two-thirds of the world’s crops, and beneficial insects play an important role in managing pest insects in agricultural farmscapes. These insects depend on nectar for their survival in these farmscapes. The flowers of tropical milkwe...

Insect transgenesis: current applications and future prospects.

Science.gov (United States)

Fraser, Malcolm J

2012-01-01

The ability to manipulate the genomes of many insects has become a practical reality over the past 15 years. This has been led by the identification of several useful transposon vector systems that have allowed the identification and development of generalized, species-specific, and tissue-specific promoter systems for controlled expression of gene products upon introduction into insect genomes. Armed with these capabilities, researchers have made significant strides in both fundamental and applied transgenics in key model systems such as Bombyx mori, Tribolium casteneum, Aedes aegypti, and Anopheles stephensi. Limitations of transposon systems were identified, and alternative tools were developed, thus significantly increasing the potential for applied transgenics for control of both agricultural and medical insect pests. The next 10 years promise to be an exciting time of transitioning from the laboratory to the field, from basic research to applied control, during which the full potential of gene manipulation in insect systems will ultimately be realized. Copyright © 2012 by Annual Reviews. All rights reserved.

Midflexion instability in primary total knee replacement: a review

Directory of Open Access Journals (Sweden)

Ramappa Manjunath

2015-01-01

Full Text Available Introduction: Midflexion instability in primary total knee replacement (TKR is an evolving concept. Successful treatment of instability requires an understanding of the different types of instability. Methods: A literature review was performed to identify information pertinent to midflexion instability in primary total knee replacement, utilising PRISMA guidelines. Databases searched included Embase, Medline, All of the Cochrane Library, PubMed and cross references. Results: Three factors, i.e., elevated joint line, multiradii femoral component and medial collateral ligament (MCL laxity, were identified to influence midflexion instability. Literature suggested mediolateral instability at 30–60° of flexion as diagnostic of midflexion instability. Literature search also revealed paucity in clinical studies analysing midflexion instability. Most of the evidence was obtained from cadaveric studies for elevated joint line and MCL laxity. Clinical studies on multiradii femoral component were limited by their small study size and early followup period. Conclusion: Elevated joint line, multiradii femoral component and MCL laxity have been suggested to cause midflexion laxity in primary TKR. Due to limitations in available evidence, this review was unable to raise the strength of overall evidence. Future well-designed clinical studies are essential to make definitive conclusions. This review serves as a baseline for future researchers and creates awareness for routine assessment of midflexion instability in primary total knee replacement.

Limited tolerance by insects to high temperatures across tropical elevational gradients and the implications of global warming for extinction.

Science.gov (United States)

García-Robledo, Carlos; Kuprewicz, Erin K; Staines, Charles L; Erwin, Terry L; Kress, W John

2016-01-19

The critical thermal maximum (CTmax), the temperature at which motor control is lost in animals, has the potential to determine if species will tolerate global warming. For insects, tolerance to high temperatures decreases with latitude, suggesting that similar patterns may exist along elevational gradients as well. This study explored how CTmax varies among species and populations of a group of diverse tropical insect herbivores, the rolled-leaf beetles, across both broad and narrow elevational gradients. Data from 6,948 field observations and 8,700 museum specimens were used to map the elevational distributions of rolled-leaf beetles on two mountains in Costa Rica. CTmax was determined for 1,252 individual beetles representing all populations across the gradients. Initial morphological identifications suggested a total of 26 species with populations at different elevations displaying contrasting upper thermal limits. However, compared with morphological identifications, DNA barcodes (cytochrome oxidase I) revealed significant cryptic species diversity. DNA barcodes identified 42 species and haplotypes across 11 species complexes. These 42 species displayed much narrower elevational distributions and values of CTmax than the 26 morphologically defined species. In general, species found at middle elevations and on mountaintops are less tolerant to high temperatures than species restricted to lowland habitats. Species with broad elevational distributions display high CTmax throughout their ranges. We found no significant phylogenetic signal in CTmax, geography, or elevational range. The narrow variance in CTmax values for most rolled-leaf beetles, especially high-elevation species, suggests that the risk of extinction of insects may be substantial under some projected rates of global warming.

Edible Insects

NARCIS (Netherlands)

Huis, van A.; Dunkel, F.V.

2016-01-01

The interest in insects as human food in the Western world is increasingly considered as a viable alternative to other protein sources. In tropical countries it is common practice and about 2000 insect species are eaten. Insects emit low levels of greenhouse gases, need little water, and require

Insects: A nutritional alternative

Science.gov (United States)

Dufour, P. A.

1981-01-01

Insects are considered as potential food sources in space. Types of insects consumed are discussed. Hazards of insect ingestion are considered. Insect reproduction, requirements, and raw materials conversion are discussed. Nutrition properties and composition of insects are considered. Preparation of insects as human food is discussed.

Edible insects are the future?

NARCIS (Netherlands)

Huis, van Arnold

2016-01-01

The global increase in demand for meat and the limited land area available prompt the search for alternative protein sources. Also the sustainability of meat production has been questioned. Edible insects as an alternative protein source for human food and animal feed are interesting in terms of

Kinetic theory of tearing instabilities

International Nuclear Information System (INIS)

Drake, J.F.; Lee, Y.C.

1977-01-01

The transition of the tearing instability from the collisional to the collisionless regime is investigated kinetically using a Fokker--Planck collision operator to represent electron-ion collisions. As a function of the collisionality of the plasma, the tearing instability falls into three regions, which are referred to as collisionless, semi-collisional, and collisional. The width Δ of the singular layer around kxB 0 =0 is limited by electron thermal motion along B 0 in the collisional and semi-collisional regimes and is typically smaller than rho/sub i/, the ion Larmor radius. Previously accepted theories, which are based on the assumption Δvery-much-greater-thanrho/sub i/, are found to be valid only in the collisional regime. The effects of density and temperature gradients on the instabilities are also studied. The tearing instability is only driven by the temperature gradient in the collisional and semi-collisional regimes. Numerical calculations indicate that the semi-collisional tearing instability is particularly relevant to present day high temperature tokamak discharges

Consuming insects

NARCIS (Netherlands)

Roos, N.; Huis, van A.

2017-01-01

How healthy are insects? This is a highly relevant question in view of the global interest in the potential of insects as a sustainable food source in food systems and diets. Edible insects, like other foods, can provide nutrients and dietary energy to meet the requirements of the human body as a

Simulation and quasilinear theory of proton firehose instability

Energy Technology Data Exchange (ETDEWEB)

Seough, Jungjoon [Korean Astronomy and Space Science Institute, Daejeon (Korea, Republic of); Faculty of Human Development, University of Toyama, 3190, Gofuku, Toyama City, Toyama, 930-8555 (Japan); Yoon, Peter H. [University of Maryland, College Park, Maryland 20742 (United States); School of Space Research, Kyung Hee University, Yongin, Gyeonggi 446-701 (Korea, Republic of); Hwang, Junga [Korean Astronomy and Space Science Institute, Daejeon (Korea, Republic of); Korea, University of Science and Technology, Daejeon (Korea, Republic of)

2015-01-15

The electromagnetic proton firehose instability is driven by excessive parallel temperature anisotropy, T{sub ∥} > T{sub ⊥} (or more precisely, parallel pressure anisotropy, P{sub ∥} > P{sub ⊥}) in high-beta plasmas. Together with kinetic instabilities driven by excessive perpendicular temperature anisotropy, namely, electromagnetic proton cyclotron and mirror instabilities, its role in providing the upper limit for the temperature anisotropy in the solar wind is well-known. A recent Letter [Seough et al., Phys. Rev. Lett. 110, 071103 (2013)] employed quasilinear kinetic theory for these instabilities to explain the observed temperature anisotropy upper bound in the solar wind. However, the validity of quasilinear approach has not been rigorously tested until recently. In a recent paper [Seough et al., Phys. Plasmas 21, 062118 (2014)], a comparative study is carried out for the first time in which quasilinear theory of proton cyclotron instability is tested against results obtained from the particle-in-cell simulation method, and it was demonstrated that the agreement was rather excellent. The present paper addresses the same issue involving the proton firehose instability. Unlike the proton cyclotron instability, however, it is found that the quasilinear approximation enjoys only a limited range of validity, especially for the wave dynamics and for the relatively high-beta regime. Possible causes and mechanisms responsible for the discrepancies are speculated and discussed.

Neonicotinoid insecticides can serve as inadvertent insect contraceptives

Science.gov (United States)

Villamar-Bouza, Laura; Bruckner, Selina; Chantawannakul, Panuwan; Gauthier, Laurent; Khongphinitbunjong, Kitiphong; Retschnig, Gina; Troxler, Aline; Vidondo, Beatriz; Neumann, Peter; Williams, Geoffrey R.

2016-01-01

There is clear evidence for sublethal effects of neonicotinoid insecticides on non-target ecosystem service-providing insects. However, their possible impact on male insect reproduction is currently unknown, despite the key role of sex. Here, we show that two neonicotinoids (4.5 ppb thiamethoxam and 1.5 ppb clothianidin) significantly reduce the reproductive capacity of male honeybees (drones), Apis mellifera. Drones were obtained from colonies exposed to the neonicotinoid insecticides or controls, and subsequently maintained in laboratory cages until they reached sexual maturity. While no significant effects were observed for male teneral (newly emerged adult) body mass and sperm quantity, the data clearly showed reduced drone lifespan, as well as reduced sperm viability (percentage living versus dead) and living sperm quantity by 39%. Our results demonstrate for the first time that neonicotinoid insecticides can negatively affect male insect reproductive capacity, and provide a possible mechanistic explanation for managed honeybee queen failure and wild insect pollinator decline. The widespread prophylactic use of neonicotinoids may have previously overlooked inadvertent contraceptive effects on non-target insects, thereby limiting conservation efforts. PMID:27466446

The phorbol ester fraction from Jatropha curcas seed oil: potential and limits for crop protection against insect pests.

Science.gov (United States)

Ratnadass, Alain; Wink, Michael

2012-11-30

The physic nut shrub, Jatropha curcas (Euphorbiaceae), has been considered as a "miracle tree", particularly as a source of alternate fuel. Various extracts of the plant have been reported to have insecticidal/acaricidal or molluscicidal/anthelminthic activities on vectors of medical or veterinary interest or on agricultural or non-agricultural pests. Among those extracts, the phorbol ester fraction from seed oil has been reported as a promising candidate for use as a plant-derived protectant of a variety of crops, from a range of pre-harvest and post-harvest insect pests. However, such extracts have not been widely used, despite the "boom" in the development of the crop in the tropics during recent years, and societal concerns about overuse of systemic chemical pesticides. There are many potential explanations to such a lack of use of Jatropha insecticidal extracts. On the one hand, the application of extracts potentially harmful to human health on stored food grain, might not be relevant. The problem of decomposition of phorbol esters and other compounds toxic to crop pests in the field needing further evaluation before such extracts can be widely used, may also be a partial explanation. High variability of phorbol ester content and hence of insecticidal activity among physic nut cultivars/ecotypes may be another. Phytotoxicity to crops may be further limitation. Apparent obstacles to a wider application of such extracts are the costs and problems involved with registration and legal approval. On the other hand, more studies should be conducted on molluscicidal activity on slugs and land snails which are major pests of crops, particularly in conservation agriculture systems. Further evaluation of toxicity to natural enemies of insect pests and studies on other beneficial insects such as pollinators are also needed.

The Phorbol Ester Fraction from Jatropha curcas Seed Oil: Potential and Limits for Crop Protection against Insect Pests

Science.gov (United States)

Ratnadass, Alain; Wink, Michael

2012-01-01

The physic nut shrub, Jatropha curcas (Euphorbiaceae), has been considered as a “miracle tree”, particularly as a source of alternate fuel. Various extracts of the plant have been reported to have insecticidal/acaricidal or molluscicidal/anthelminthic activities on vectors of medical or veterinary interest or on agricultural or non-agricultural pests. Among those extracts, the phorbol ester fraction from seed oil has been reported as a promising candidate for use as a plant-derived protectant of a variety of crops, from a range of pre-harvest and post-harvest insect pests. However, such extracts have not been widely used, despite the “boom” in the development of the crop in the tropics during recent years, and societal concerns about overuse of systemic chemical pesticides. There are many potential explanations to such a lack of use of Jatropha insecticidal extracts. On the one hand, the application of extracts potentially harmful to human health on stored food grain, might not be relevant. The problem of decomposition of phorbol esters and other compounds toxic to crop pests in the field needing further evaluation before such extracts can be widely used, may also be a partial explanation. High variability of phorbol ester content and hence of insecticidal activity among physic nut cultivars/ecotypes may be another. Phytotoxicity to crops may be further limitation. Apparent obstacles to a wider application of such extracts are the costs and problems involved with registration and legal approval. On the other hand, more studies should be conducted on molluscicidal activity on slugs and land snails which are major pests of crops, particularly in conservation agriculture systems. Further evaluation of toxicity to natural enemies of insect pests and studies on other beneficial insects such as pollinators are also needed. PMID:23203190

Do Native Insects and Associated Fungi Limit Non-Native Woodwasp, Sirex noctilio, Survival in a Newly Invaded Environment?

Directory of Open Access Journals (Sweden)

Laurel J Haavik

Full Text Available Sirex noctilio F. (Hymenoptera: Siricidae is an introduced pest of pines (Pinus spp. in several countries in the Southern Hemisphere. Although S. noctilio is established in North America (first discovered in 2004, it has not been a destructive pest there so far, where forest communities more closely resemble those in its native Eurasian range—where it is not a pest. To investigate the influence of the existing community of associated insects (competitors + natural enemies and fungi (vectored by insects on S. noctilio survival in North America, we examined stage-specific mortality factors and their relative importance, generating life tables drawn from experimentally-manipulated and natural cohorts of Sirex spp. (mostly S. noctilio, but some native S. nigricornis F.. For both natural and experimentally-manipulated cohorts, factors which acted during the earliest Sirex life stages, most likely tree resistance and/or competition among fungal associates, were paramount in dictating woodwasp survival. Experimentally-manipulated life tables revealed that protection from the community of associates resulted in a significantly, and substantially larger (>15x S. noctilio F1 generation than exposure to it. Seventy percent of generation mortality in the exposed cohort was due to tree resistance or unknown causes early in larval development, which could have included competition among other bark- or wood-inhabiting insects and/or their fungal associates. Only 46% of generation mortality in the protected cohort was due to tree resistance and/or unknown causes. Parasitoids, particularly endoparasitoids (Ibalia spp., showed limited ability to control S. noctilio, and reduced the experimentally-established cohort by only 11%, and natural cohorts an average of 3.4%. The relative importance of tree resistance vs. competition with bark- and wood-borers in reducing S. noctilio survival remains unclear. Tree resistance and/or competition likely contribute more

All insects are equal, but some insects are more equal than others

OpenAIRE

Fischer, Arnout R.H.; Steenbekkers, L.P.A.

2018-01-01

Purpose: Lack of acceptance of insects as food is considered a barrier against societal adoption of the potentially valuable contribution of insects to human foods. An underlying barrier may be that insects are lumped together as one group, while consumers typically try specific insects. The purpose of this paper is to investigate the ways in which Dutch consumers, with and without insect tasting experience, are more or less willing to eat different insects. Design/methodology/approach: In a ...

Suppressing Resistance to Bt Cotton with Sterile Insect Releases

Energy Technology Data Exchange (ETDEWEB)

Tabashnik, B E [Department of Entomology, University of Arizona, Tucson, AZ (United States); Sisterson, M S [USDA-ARS, San Joaquin Valley Agricultural Sciences Center, Parlier, CA (United States); Ellsworth, P C [Department of Entomology, University of Arizona, Maricopa Agricultural Center, Maricopa, AZ (United States)

2011-01-15

Genetically engineered crops that produce insecticidal toxins from Bacillus thuringiensis (Bt) are grown widely for pest control. However, insect adaptation can reduce the toxins' efficacy. The predominant strategy for delaying pest resistance to Bt crops requires refuges of non-Bt host plants to provide susceptible insects to mate with resistant insects. Variable farmer compliance is one of the limitations of this approach. Here we report the benefits of an alternative strategy where sterile insects are released to mate with resistant insects and refuges are scarce or absent. Computer simulations show that this approach works in principle against pests with recessive or dominant inheritance of resistance. During a largescale, four-year field deployment of this strategy in Arizona, resistance of pink bollworm (Pectinophora gossypiella) to Bt cotton did not increase. A multitactic eradication program that included the release of sterile moths reduced pink bollworm abundance by >99%, while eliminating insecticide sprays against this key invasive pest. (author)

Centrifugally Driven Rayleigh-Taylor Instability

Science.gov (United States)

Scase, Matthew; Hill, Richard

2017-11-01

The instability that develops at the interface between two fluids of differing density due to the rapid rotation of the system may be considered as a limit of high-rotation rate Rayleigh-Taylor instability. Previously the authors have considered the effect of rotation on a gravitationally dominated Rayleigh-Taylor instability and have shown that some growth modes of instability may be suppressed completely by the stabilizing effect of rotation (Phys. Rev. Fluids 2:024801, Sci. Rep. 5:11706). Here we consider the case of very high rotation rates and a negligible gravitational field. The initial condition is of a dense inner cylinder of fluid surrounded by a lighter layer of fluid. As the system is rotated about the generating axis of the cylinder, the dense inner fluid moves away from the axis and the familiar bubbles and spikes of Rayleigh-Taylor instability develop at the interface. The system may be thought of as a ``fluid-fluid centrifuge''. By developing a model based on an Orr-Sommerfeld equation, we consider the effects of viscosity, surface tension and interface diffusion on the growth rate and modes of instability. We show that under particular circumstances some modes may be stabilized. School of Mathematical Sciences.

Plant odour plumes as mediators of plant-insect interactions.

Science.gov (United States)

Beyaert, Ivo; Hilker, Monika

2014-02-01

Insect olfactory orientation along odour plumes has been studied intensively with respect to pheromonal communication, whereas little knowledge is available on how plant odour plumes (POPs) affect olfactory searching by an insect for its host plants. The primary objective of this review is to examine the role of POPs in the attraction of insects. First, we consider parameters of an odour source and the environment which determine the size, shape and structure of an odour plume, and we apply that knowledge to POPs. Second, we compare characteristics of insect pheromonal plumes and POPs. We propose a 'POP concept' for the olfactory orientation of insects to plants. We suggest that: (i) an insect recognises a POP by means of plant volatile components that are encountered in concentrations higher than a threshold detection limit and that occur in a qualitative and quantitative blend indicating a resource; (ii) perception of the fine structure of a POP enables an insect to distinguish a POP from an unspecific odorous background and other interfering plumes; and (iii) an insect can follow several POPs to their sources, and may leave the track of one POP and switch to another one if this conveys a signal with higher reliability or indicates a more suitable resource. The POP concept proposed here may be a useful tool for research in olfactory-mediated plant-insect interactions. © 2013 The Authors. Biological Reviews © 2013 Cambridge Philosophical Society.

Upper Extremity Injured Workers Stratified by Current Work Status: An Examination of Health Characteristics, Work Limitations and Work Instability

Directory of Open Access Journals (Sweden)

D Pichora

2010-06-01

Full Text Available Background: Upper extremity injured workers are an under-studied population. A descriptive comparison of workers with shoulder, elbow and hand injuries reporting to a Canadian Workplace Safety and Insurance Board (WSIB clinic was undertaken. Objective: To determine if differences existed between injury groups stratified by current work status. Methods: All WSIB claimants reporting to our upper extremity clinic between 2003 and 2008 were approached to participate in this descriptive study. 314 working and 146 non-working WSIB claimants completed the Disabilities of the Arm, Shoulder and Hand questionnaire (DASH; Short Form health survey (SF36; Worker’s Limitations Questionnaire and the Work Instability Scale. Various parametric and non-parametric analyses were used to assess significant differences between groups on demographic, work and health related variables. Results: Hand, followed by the shoulder and elbow were the most common site of injury. Most non-workers listed their current injury as the reason for being off work, and attempted to return to work once since their injury occurrence. Non-workers and a subset of workers at high risk for work loss showed significantly worse mental functioning. Workers identified physical demands as the most frequent injury-related on the job limitation. 60% of current workers were listed as low risk for work loss on the Work Instability Scale. Conclusions: Poorer mental functioning, being female and sustaining a shoulder injury were risk factors for work instability. Our cohort of injured non-workers were unable to return to work due to their current injury, reinforcing the need to advocate for modified duties, shorter hours and a work environment where stress and injury recurrence is reduced. Future studies examining pre-injury depression as a risk factor for prolonged work absences are warranted.

Nonlinear Development and Secondary Instability of Traveling Crossflow Vortices

Science.gov (United States)

Li, Fei; Choudhari, Meelan M.; Duan, Lian; Chang, Chau-Lyan

2014-01-01

Transition research under NASA's Aeronautical Sciences Project seeks to develop a validated set of variable fidelity prediction tools with known strengths and limitations, so as to enable "sufficiently" accurate transition prediction and practical transition control for future vehicle concepts. This paper builds upon prior effort targeting the laminar breakdown mechanisms associated with stationary crossflow instability over a swept-wing configuration relevant to subsonic aircraft with laminar flow technology. Specifically, transition via secondary instability of traveling crossflow modes is investigated as an alternate scenario for transition. Results show that, for the parameter range investigated herein, secondary instability of traveling crossflow modes becomes insignificant in relation to the secondary instability of the stationary modes when the relative initial amplitudes of the traveling crossflow instability are lower than those of the stationary modes by approximately two orders of magnitudes or more. Linear growth predictions based on the secondary instability theory are found to agree well with those based on PSE and DNS, with the most significant discrepancies being limited to spatial regions of relatively weak secondary growth, i.e., regions where the primary disturbance amplitudes are smaller in comparison to its peak amplitude. Nonlinear effects on secondary instability evolution is also investigated and found to be initially stabilizing, prior to breakdown.

Continental drift and climate change drive instability in insect assemblages

Science.gov (United States)

Li, Fengqing; Tierno de Figueroa, José Manuel; Lek, Sovan; Park, Young-Seuk

2015-06-01

Global change has already had observable effects on ecosystems worldwide, and the accelerated rate of global change is predicted in the future. However, the impacts of global change on the stability of biodiversity have not been systematically studied in terms of both large spatial (continental drift) and temporal (from the last inter-glacial period to the next century) scales. Therefore, we analyzed the current geographical distribution pattern of Plecoptera, a thermally sensitive insect group, and evaluated its stability when coping with global change across both space and time throughout the Mediterranean region—one of the first 25 global biodiversity hotspots. Regional biodiversity of Plecoptera reflected the geography in both the historical movements of continents and the current environmental conditions in the western Mediterranean region. The similarity of Plecoptera assemblages between areas in this region indicated that the uplift of new land and continental drift were the primary determinants of the stability of regional biodiversity. Our results revealed that climate change caused the biodiversity of Plecoptera to slowly diminish in the past and will cause remarkably accelerated biodiversity loss in the future. These findings support the theory that climate change has had its greatest impact on biodiversity over a long temporal scale.

New directions in diagnostic evaluation of insect allergy.

Science.gov (United States)

Golden, David B K

2014-08-01

Diagnosis of insect sting allergy and prediction of risk of sting anaphylaxis are often difficult because tests for venom-specific IgE antibodies have a limited positive predictive value and do not reliably predict the severity of sting reactions. Component-resolved diagnosis using recombinant venom allergens has shown promise in improving the specificity of diagnostic testing for insect sting allergy. Basophil activation tests have been explored as more sensitive assays for identification of patients with insect allergy and for prediction of clinical outcomes. Measurement of mast cell mediators reflects the underlying risk for more severe reactions and limited clinical response to treatment. Measurement of IgE to recombinant venom allergens can distinguish cross-sensitization from dual sensitization to honeybee and vespid venoms, thus helping to limit venom immunotherapy to a single venom instead of multiple venoms in many patients. Basophil activation tests can detect venom allergy in patients who show no detectable venom-specific IgE in standard diagnostic tests and can predict increased risk of systemic reactions to venom immunotherapy, and to stings during and after stopping venom immunotherapy. The risk of severe or fatal anaphylaxis to stings can also be predicted by measurement of baseline serum tryptase or other mast cell mediators.

Insects and Scorpions

Science.gov (United States)

... insects or scorpions can be hazardous to outdoor workers. Stinging or biting insects include bees, wasps, hornets, and fire ants. The health effects of stinging or biting insects or scorpions range ...

Review of food composition data for edible insects.

Science.gov (United States)

Nowak, Verena; Persijn, Diedelinde; Rittenschober, Doris; Charrondiere, U Ruth

2016-02-15

Edible insects are considered rich in protein and a variety of micronutrients, and are therefore seen as potential contributors to food security. However, the estimation of the insects' contribution to the nutrient intake is limited since data are absent in food composition tables and databases. Therefore, FAO/INFOODS collected and published analytical data from primary sources with sufficient quality in the Food Composition Database for Biodiversity (BioFoodComp). Data were compiled for 456 food entries on insects in different developmental stages. A total of 5734 data points were entered, most on minerals and trace elements (34.8%), proximates (24.5%), amino acids (15.3%) and (pro)vitamins (9.1%). Data analysis of Tenebrio molitor confirms its nutritive quality that can help to combat malnutrition. The collection of data will assist compilers to incorporate more insects into tables and databases, and to further improve nutrient intake estimations. Copyright © 2015 Food and Agriculture Organization of the United Nations. Published by Elsevier Ltd.. All rights reserved.

Comments on the theory of absolute and convective instabilities

International Nuclear Information System (INIS)

Oscarsson, T.E.; Roennmark, K.

1986-10-01

The theory of absolute and convective instabilities is discussed and we argue that the basis of the theory is questionable, since it describes the linear development of instabilities by their behaviour in the time asymptotic limit. In order to make sensible predictions on the linear development of instabilities, the problem should be studied on the finite time scale implied by the linear approximation. (authors)

An immunological axis of biocontrol: infections in field-trapped insects

Science.gov (United States)

Tunaz, Hasan; Stanley, David

2009-09-01

Insect immunology is an active research arena, however, the vast majority of research in the area is conducted on model species taken from laboratory cultures. We tested the hypothesis that insects are regularly exposed to infections or invasions in nature and here report results of a field study designed to assess the extent of natural infections in insects collected from agrarian fields surrounding Kahramanmaraş, Turkey. Specimens were dissected to assess numbers of nodules. Formation of darkened, melanotic nodules is the predominant cellular immune reaction to microbial and parasitic infection, and once formed, the nodules are permanently attached to internal surfaces. The collected insects were healthy. Of the >400 examined specimens, at least some nodules were found in 98%. Numbers of nodules ranged from ˜2/individual to >100 nodules/individual. We conclude that insects are regularly challenged by microbial and parasitic infections from which they recover. The novel implication of our data is that insect immune systems may limit the host range and effectiveness of agents deployed in biological control programs. Knowledge of insect immune systems may contribute to increased use of biopesticides globally.

Coulomb Fission in Multiply-Charged Ammonia Clusters: Accurate Measurements of the Rayleigh Instability Limit from Fragmentation Patterns.

Science.gov (United States)

Harris, Christopher; Stace, Anthony J

2018-03-15

A series of experiments have been undertaken on the fragmentation of multiply charged ammonia clusters, (NH 3 ) n z+ , where z ≤ 8 and n ≤ 850, to establish Rayleigh instability limits, whereby clusters at certain critical sizes become unstable due to Coulomb repulsion between the resident charges. Experimental results on size-selected clusters are found to be in excellent agreement with theoretical predictions of Rayleigh instability limits at all values of the charge. Electrostatic theory has been used to help identify fragmentation patterns on the assumption that the clusters separate into two dielectric spheres, and the predicted Coulomb repulsion energies used to establish pathways and the sizes of cluster fragments. The results show that fragmentation is very asymmetric in terms of both the numbers of molecules involved and the amount of charge each fragment accommodates. For clusters carrying a charge ≤+4, the results show that fragmentation proceeds via the loss of small, singly charged clusters. When clusters carry a charge of +5 or more, the experimental observations suggest a marked switch in behavior. Although the laboratory measurements equate to fragmentation via the loss of a large dication cluster, electrostatic theory supports an interpretation that involves the sequential loss of two smaller, singly charged clusters possibly accompanied by the extensive evaporation of neutral molecules. It is suggested that this change in fragmentation pattern is driven by the channelling of Coulomb repulsion energy into intermolecular modes within these larger clusters. Overall, the results appear to support the ion evaporation model that is frequently used to interpret electrospray experiments.

All insects are equal, but some insects are more equal than others

NARCIS (Netherlands)

Fischer, Arnout R.H.; Steenbekkers, L.P.A.

2018-01-01

Purpose: Lack of acceptance of insects as food is considered a barrier against societal adoption of the potentially valuable contribution of insects to human foods. An underlying barrier may be that insects are lumped together as one group, while consumers typically try specific insects. The purpose

Limitations of rotational manoeuvrability in insects and hummingbirds: evaluating the effects of neuro-biomechanical delays and muscle mechanical power.

Science.gov (United States)

Liu, Pan; Cheng, Bo

2017-07-01

Flying animals ranging in size from fruit flies to hummingbirds are nimble fliers with remarkable rotational manoeuvrability. The degrees of manoeuvrability among these animals, however, are noticeably diverse and do not simply follow scaling rules of flight dynamics or muscle power capacity. As all manoeuvres emerge from the complex interactions of neural, physiological and biomechanical processes of an animal's flight control system, these processes give rise to multiple limiting factors that dictate the maximal manoeuvrability attainable by an animal. Here using functional models of an animal's flight control system, we investigate the effects of three such limiting factors, including neural and biomechanical (from limited flapping frequency) delays and muscle mechanical power, for two insect species and two hummingbird species, undergoing roll, pitch and yaw rotations. The results show that for animals with similar degree of manoeuvrability, for example, fruit flies and hummingbirds, the underlying limiting factors are different, as the manoeuvrability of fruit flies is only limited by neural delays and that of hummingbirds could be limited by all three factors. In addition, the manoeuvrability also appears to be the highest about the roll axis as it requires the least muscle mechanical power and can tolerate the largest neural delays. © 2017 The Author(s).

Insect Repellents: Protect Your Child from Insect Bites

Science.gov (United States)

... Español Text Size Email Print Share Choosing an Insect Repellent for Your Child Page Content Mosquitoes, biting ... sunscreen needs to be reapplied often. Reactions to Insect Repellents If you suspect that your child is ...

Dynamical instability of the envelope of red supergiants and the lower mass limit for carbon detonation supernovae

International Nuclear Information System (INIS)

Fujimoto, M.Y.; Nomoto, K.; Sugimoto, D.

1976-01-01

The lower mass limit Msub(l) for the carbon detonation supernovae was investigated by testing the dynamical instability of the envelopes of red supergiants. It was found that the dependence of Msub(l) on the mixing length l of convection is appreciable. As a smaller value of l is assumed, Msub(l) becomes larger. It may be as large as 8 solar masses if l is a third of the pressure scale-height. This is one of the ways to remove the difficulty of overproduction of iron-peak elements involved in the model of the carbon detonation supernovae. (Auth.)

Dynamical instability of the envelope of red supergiants and the lower mass limit for carbon detonation supernovae

Energy Technology Data Exchange (ETDEWEB)

Fujimoto, M Y [Tokyo Univ. (Japan); Nomoto, K; Sugimoto, D [Tokyo Univ. (Japan). Coll. of General Education

1976-11-01

The lower mass limit Msub(l) for the carbon detonation supernovae was investigated by testing the dynamical instability of the envelopes of red supergiants. It was found that the dependence of Msub(l) on the mixing length l of convection is appreciable. As a smaller value of l is assumed, Msub(l) becomes larger. It may be as large as 8 solar masses if l is a third of the pressure scale-height. This is one of the ways to remove the difficulty of overproduction of iron-peak elements involved in the model of the carbon detonation supernovae.

Instabilities of collisionless current sheets: Theory and simulations

International Nuclear Information System (INIS)

Silin, I.; Buechner, J.; Zelenyi, L.

2002-01-01

The problem of Harris current sheet stability is investigated. A linear dispersion relation in the long-wavelength limit is derived for instabilities, propagating in the neutral plane at an arbitrary angle to the magnetic field but symmetric across the sheet. The role of electrostatic perturbations is especially investigated. It appears, that for the tearing-mode instability electrostatic effects are negligible. However, for obliquely propagating modes the modulation of the electrostatic potential φ is essential. In order to verify the theoretical results, the limiting cases of tearing and sausage instabilities are compared to the two-dimensional (2D) Vlasov code simulations. For tearing the agreement between theory and simulations is good for all mass ratios. For sausage-modes, the theory predicts fast stabilization for mass ratios m i /m e ≥10. This is not observed in simulations due to the diminishing of the wavelength for higher mass ratios, which leads beyond the limit of applicability of the theory developed here

Harnessing Insect-Microbe Chemical Communications To Control Insect Pests of Agricultural Systems.

Science.gov (United States)

Beck, John J; Vannette, Rachel L

2017-01-11

Insect pests cause serious economic, yield, and food safety problems to managed crops worldwide. Compounding these problems, insect pests often vector pathogenic or toxigenic microbes to plants. Previous work has considered plant-insect and plant-microbe interactions separately. Although insects are well-understood to use plant volatiles to locate hosts, microorganisms can produce distinct and abundant volatile compounds that in some cases strongly attract insects. In this paper, we focus on the microbial contribution to plant volatile blends, highlighting the compounds emitted and the potential for variation in microbial emission. We suggest that these aspects of microbial volatile emission may make these compounds ideal for use in agricultural applications, as they may be more specific or enhance methods currently used in insect control or monitoring. Our survey of microbial volatiles in insect-plant interactions suggests that these emissions not only signal host suitability but may indicate a distinctive time frame for optimal conditions for both insect and microbe. Exploitation of these host-specific microbe semiochemicals may provide important microbe- and host-based attractants and a basis for future plant-insect-microbe chemical ecology investigations.

A nuclear insect appears

International Nuclear Information System (INIS)

Shin, Gi Hwal

1989-06-01

This book is dairy of a nuclear insect in A. F. era. It consists of 6 parts, which have fun pictures and titles. The contents are the letter that is sent the Homo sapiens by insect, exodus of nuclear insect F 100 years latter. The time that a nuclear insect is attacked in F 101, the time that a nuclear dinosaur is beat in AF 102, the time that a nuclear insect struggles in AF 104 and the time that a nuclear insect drifts in AF 104.

Diversity, evolution and medical applications of insect antimicrobial peptides

OpenAIRE

Mylonakis, Eleftherios; Podsiadlowski, Lars; Muhammed, Maged; Vilcinskas, Andreas

2016-01-01

Antimicrobial peptides (AMPs) are short proteins with antimicrobial activity. A large portion of known AMPs originate from insects, and the number and diversity of these molecules in different species varies considerably. Insect AMPs represent a potential source of alternative antibiotics to address the limitation of current antibiotics, which has been caused by the emergence and spread of multidrug-resistant pathogens. To get more insight into AMPs, we investigated the diversity and evolutio...

Stinging Insect Matching Game

Science.gov (United States)

... for Kids ▸ Stinging Insect Matching Game Share | Stinging Insect Matching Game Stinging insects can ruin summer fun for those who are ... the difference between the different kinds of stinging insects in order to keep your summer safe and ...

Insect population control by the sterile-male technique

International Nuclear Information System (INIS)

Lindquist, A.W.

1963-01-01

The successful use of the sterile male technique to eradicate the screw worm fly from the Southeastern part of the United States showed that a new biological method using radiation-sterilized insects could not only control but also eradicate harmful insect pests. A panel of experts met at the IAEA in Vienna in October 1962 to discuss the various aspects and applications of this new technique and to assess its usefulness and limitations. This report summarizes the panel proceedings. 42 refs, 18 figs, 1 tab

Insect population control by the sterile-male technique

Energy Technology Data Exchange (ETDEWEB)

Lindquist, A W

1963-10-01

The successful use of the sterile male technique to eradicate the screw worm fly from the Southeastern part of the United States showed that a new biological method using radiation-sterilized insects could not only control but also eradicate harmful insect pests. A panel of experts met at the IAEA in Vienna in October 1962 to discuss the various aspects and applications of this new technique and to assess its usefulness and limitations. This report summarizes the panel proceedings. 42 refs, 18 figs, 1 tab.

Marine insects

National Research Council Canada - National Science Library

Cheng, Lanna

1976-01-01

.... Not only are true insects, such as the Collembola and insect parasites of marine birds and mammals, considered, but also other kinds of intertidal air-breathing arthropods, notably spiders, scorpions...

RINGED ACCRETION DISKS: INSTABILITIES

Energy Technology Data Exchange (ETDEWEB)

Pugliese, D.; Stuchlík, Z., E-mail: d.pugliese.physics@gmail.com, E-mail: zdenek.stuchlik@physics.cz [Institute of Physics and Research Centre of Theoretical Physics and Astrophysics, Faculty of Philosophy and Science, Silesian University in Opava, Bezručovo náměstí 13, CZ-74601 Opava (Czech Republic)

2016-04-01

We analyze the possibility that several instability points may be formed, due to the Paczyński mechanism of violation of mechanical equilibrium, in the orbiting matter around a supermassive Kerr black hole. We consider a recently proposed model of a ringed accretion disk, made up by several tori (rings) that can be corotating or counter-rotating relative to the Kerr attractor due to the history of the accretion process. Each torus is governed by the general relativistic hydrodynamic Boyer condition of equilibrium configurations of rotating perfect fluids. We prove that the number of the instability points is generally limited and depends on the dimensionless spin of the rotating attractor.

Nonlinear evolution of the sausage instability

International Nuclear Information System (INIS)

Book, D.L.; Ott, E.; Lampe, M.

1976-01-01

Sausage instabilities of an incompressible, uniform, perfectly conducting Z pinch are studied in the nonlinear regime. In the long wavelength limit (analogous to the ''shallow water theory'' of hydrodynamics), a simplified set of universal fluid equations is derived, with no radial dependence, and with all parameters scaled out. Analytic and numerical solutions of these one-dimensional equations show that an initially sinusoidal perturbation grows into a ''spindle'' or cylindrical ''spike and bubble'' shape, with sharp radial maxima. In the short wavelength limit, the problem is shown to be mathematically equivalent to the planar semi-infinite Rayleigh--Taylor instability, which also grows into a spike-and-bubble shape. Since the spindle shape is common to both limits, it is concluded that it probably obtains in all cases. The results are in agreement with dense plasma focus experiments

MHD stability, operational limits and disruptions

International Nuclear Information System (INIS)

1999-01-01

The present physics understandings of magnetohydrodynamic (MHD) stability of tokamak plasmas, the threshold conditions for onset of MHD instability, and the resulting operational limits on attainable plasma pressure (beta limit) and density (density limit), and the consequences of plasma disruption and disruption related effects are reviewed and assessed in the context of their application to a future DT burning reactor prototype tokamak experiment such as ITER. The principal considerations covered within the MHD stability and beta limit assessments are (i) magnetostatic equilibrium, ideal MHD stability and the resulting ideal MHD beta limit; (ii) sawtooth oscillations and the coupling of sawtooth activity to other types of MHD instability; (iii) neoclassical island resistive tearing modes and the corresponding limits on beta and energy confinement; (iv) wall stabilization of ideal MHD instabilities and resistive wall instabilities; (v) mode locking effects of non-axisymmetric error fields; (vi) edge localized MHD instabilities (ELMs, etc.); and (vii) MHD instabilities and beta/pressure gradient limits in plasmas with actively modified current and magnetic shear profiles. The principal considerations covered within the density limit assessments are (i) empirical density limits; (ii) edge power balance/radiative density limits in ohmic and L-mode plasmas; and (iii) edge parameter related density limits in H-mode plasmas. The principal considerations covered in the disruption assessments are (i) disruption causes, frequency and MHD instability onset; (ii) disruption thermal and current quench characteristics; (iii) vertical instabilities (VDEs), both before and after disruption, and plasma and in-vessel halo currents; (iv) after disruption runaway electron formation, confinement and loss; (v) fast plasma shutdown (rapid externally initiated dissipation of plasma thermal and magnetic energies); (vi) means for disruption avoidance and disruption effect mitigation; and

Applying the sterile insect technique to the control of insect pests

International Nuclear Information System (INIS)

LaChance, L.E.; Klassen, W.

1991-01-01

The sterile insect technique (SIT) is basically a novel twentieth century approach to insect birth control. It is species specific and exploits the mate seeking behaviour of the insect. The basic principle is simple. Insects are mass reared in 'factories' and sexually sterilized by gamma rays from a 60 Co source. The sterile insects are then released in a controlled fashion into nature. Matings between the sterile insects released and native insects produced no progeny. If enough of these matings take place, reproduction of the pest population decreases. With continued release, the pest population can be controlled and in some cases eradicated. In the light of the many important applications of the SIT worldwide and the great potential that SIT concepts hold for insect and pest control in developing countries, two special benefits should be stressed. Of greatest significance is the fact that the SIT permits suppression and eradication of insect pests in an environmentally harmless manner. It combines nuclear techniques with genetic approaches and, in effect, replaces intensive use of chemicals in pest control. Although chemicals are used sparingly at the outset in some SIT programmes to reduce the size of the pest population before releases of sterilized insects are started, the total amount of chemicals used in an SIT programme is a mere fraction of what would be used without the SIT. It is also of great importance that the SIT is not designed strictly for the eradication of pest species but can readily be used in the suppression of insect populations. In fact, the SIT is ideally suited for use in conjunction with other agricultural pest control practices such as the use of parasites and predators, attractants and cultural controls (e.g. ploughing under or destruction of crop residues) in integrated pest management programmes to achieve control at the lowest possible price and with a minimum of chemical contamination of the environment

Applying the sterile insect technique to the control of insect pests

Energy Technology Data Exchange (ETDEWEB)

LaChance, L E; Klassen, W [Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Vienna (Austria)

1991-09-01

The sterile insect technique (SIT) is basically a novel twentieth century approach to insect birth control. It is species specific and exploits the mate seeking behaviour of the insect. The basic principle is simple. Insects are mass reared in 'factories' and sexually sterilized by gamma rays from a {sup 60}Co source. The sterile insects are then released in a controlled fashion into nature. Matings between the sterile insects released and native insects produced no progeny. If enough of these matings take place, reproduction of the pest population decreases. With continued release, the pest population can be controlled and in some cases eradicated. In the light of the many important applications of the SIT worldwide and the great potential that SIT concepts hold for insect and pest control in developing countries, two special benefits should be stressed. Of greatest significance is the fact that the SIT permits suppression and eradication of insect pests in an environmentally harmless manner. It combines nuclear techniques with genetic approaches and, in effect, replaces intensive use of chemicals in pest control. Although chemicals are used sparingly at the outset in some SIT programmes to reduce the size of the pest population before releases of sterilized insects are started, the total amount of chemicals used in an SIT programme is a mere fraction of what would be used without the SIT. It is also of great importance that the SIT is not designed strictly for the eradication of pest species but can readily be used in the suppression of insect populations. In fact, the SIT is ideally suited for use in conjunction with other agricultural pest control practices such as the use of parasites and predators, attractants and cultural controls (e.g. ploughing under or destruction of crop residues) in integrated pest management programmes to achieve control at the lowest possible price and with a minimum of chemical contamination of the environment.

Temperature-gradient instability induced by conducting end walls

International Nuclear Information System (INIS)

Berk, H.L.; Ryutov, D.D.; Tsidulko, Yu.A.

1990-04-01

A new rapidly growing electron temperature gradient instability is found for a plasma in contact with a conducting wall. The linear instability analysis is presented and speculations are given for its nonlinear consequences. This instability illustrates that conducting walls can produce effects that are detrimental to plasma confinement. This mode should be of importance in open-ended systems including astrophysical plasmas, mirror machines and at the edge of tokamaks where field lines are open and are connected to limiters or divertors. 16 refs., 2 figs

Resilience of quasi-isodynamic stellarators against trapped-particle instabilities.

Science.gov (United States)

Proll, J H E; Helander, P; Connor, J W; Plunk, G G

2012-06-15

It is shown that in perfectly quasi-isodynamic stellarators, trapped particles with a bounce frequency much higher than the frequency of the instability are stabilizing in the electrostatic and collisionless limit. The collisionless trapped-particle instability is therefore stable as well as the ordinary electron-density-gradient-driven trapped-electron mode. This result follows from the energy balance of electrostatic instabilities and is thus independent of all other details of the magnetic geometry.

Instabilities simulations with wideband feedback systems: CMAD, HEADTAIL, WARP

International Nuclear Information System (INIS)

Li, Kevin; Cesaratto, J; Fox, J D; Pivi, M; Rivetta, C; Rumolo, G

2013-01-01

Transverse mode coupling (TMCI) and electron cloud instabilities (ECI) pose fundamental limitations on the acceptable beam intensities in the SPS at CERN. This in turn limits the ultimate achievable luminosity in the LHC. Therefore, future luminosity upgrades foresee methods for evading TMCI as well as ECI. Proposed approaches within the LHC Injector Upgrade (LIU) project include new optics with reduced transition energy as well as vacuum chamber coating techniques. As a complementary option, high bandwidth feedback systems may provide instability mitigation by actively damping the intra-bunch motion of unstable modes. In an effort to evaluate the potentials and limitations of such feedback systems and to characterise some of the specifications, a numerical model of a realistic feedback system has been developed and integrated into available instabilities simulation codes. Together with the implementation of this new feedback system model, CMAD and HEADTAIL have been used to investigate the impact of different wideband feedback systems on ECI in the SPS. In this paper, we present some details on the numerical model of the realistic feedback system and its implementation as well as the results obtained from the simulation study using this model together with the instability codes. (author)

Macronutrient contributions of insects to the diets of hunter-gatherers: a geometric analysis.

Science.gov (United States)

Raubenheimer, David; Rothman, Jessica M; Pontzer, Herman; Simpson, Stephen J

2014-06-01

We present a geometric model for examining the macronutrient contributions of insects in the diets of pre-agricultural humans, and relate the findings to some contemporary societies that regularly eat insects. The model integrates published data on the macronutrient composition of insects and other foods in the diets of humans, recommended human macronutrient intakes, and estimated macronutrient intakes to examine the assumption that insects provided to pre-agricultural humans an invertebrate equivalent of vertebrate-derived meats, serving primarily as a source of protein. Our analysis suggests that insects vary more widely in their macronutrient content than is likely to be the case for most wild vertebrate meats, spanning a broad range of protein, fat and carbohydrate concentrations. Potentially, therefore, in terms of their proportional macronutrient composition, insects could serve as equivalents not only of wild meat, but of a range of other foods including some shellfish, nuts, pulses, vegetables and even fruits. Furthermore, humans might systematically manipulate the composition of edible insects to meet specific needs through pre-ingestive processing, such as cooking and selective removal of body parts. We present data suggesting that in modern societies for which protein is the more limiting macronutrient, pre-ingestive processing of edible insects might serve to concentrate protein. It is likely, however, that the dietary significance of insects was different for Paleolithic hunter-gatherers who were more limited in non-protein energy. Our conclusions are constrained by available data, but highlight the need for further studies, and suggest that our model provides an integrative framework for conceiving these studies. Copyright © 2014 Elsevier Ltd. All rights reserved.

Instabilities simulations with wideband feedback systems: CMAD, HEADTAIL, WARP

CERN Document Server

Li, Kevin; Fox, J D; Pivi, M; Rivetta, C; Rumolo, G

2013-01-01

Transverse mode coupling (TMCI) and electron cloud instabilities (ECI) pose fundamental limitations on the acceptable beam intensities in the SPS at CERN. This in turn limits the ultimate achievable luminosity in the LHC. Therefore, future luminosity upgrades foresee methods for evading TMCI as well as ECI. Proposed approaches within the LHC Injector Upgrade (LIU) project include new optics with reduced transition energy as well as vacuum chamber coating techniques. As a complementary option, high bandwidth feedback systems may provide instability mitigation by actively damping the intra-bunch motion of unstable modes. In an effort to evaluate the potentials and limitations of such feedback systems and to characterise some of the specifications, a numerical model of a realistic feedback system has been developed and integrated into available instabilities simulation codes. Together with the implementation of this new feedback system model, CMAD and HEADTAIL have been used to investigate the impact of differen...

Insects, isotopes and radiation

International Nuclear Information System (INIS)

Lindquist, D.A.

1987-01-01

The article describes the increased use of nuclear techniques in controlling harmful insects. The sterile insect technique (SIT), which uses radiation to sexually sterilize insects and prevent reproduction, is particularly effective in eradication programmes. At the present time, there are approximately 10 species of insect pests being attacked by the SIT. Research and development is being conducted on other insect species and it is anticipated that the technology will be more widely used in the future

Lattice Boltzmann methods for global linear instability analysis

Science.gov (United States)

Pérez, José Miguel; Aguilar, Alfonso; Theofilis, Vassilis

2017-12-01

Modal global linear instability analysis is performed using, for the first time ever, the lattice Boltzmann method (LBM) to analyze incompressible flows with two and three inhomogeneous spatial directions. Four linearization models have been implemented in order to recover the linearized Navier-Stokes equations in the incompressible limit. Two of those models employ the single relaxation time and have been proposed previously in the literature as linearization of the collision operator of the lattice Boltzmann equation. Two additional models are derived herein for the first time by linearizing the local equilibrium probability distribution function. Instability analysis results are obtained in three benchmark problems, two in closed geometries and one in open flow, namely the square and cubic lid-driven cavity flow and flow in the wake of the circular cylinder. Comparisons with results delivered by classic spectral element methods verify the accuracy of the proposed new methodologies and point potential limitations particular to the LBM approach. The known issue of appearance of numerical instabilities when the SRT model is used in direct numerical simulations employing the LBM is shown to be reflected in a spurious global eigenmode when the SRT model is used in the instability analysis. Although this mode is absent in the multiple relaxation times model, other spurious instabilities can also arise and are documented herein. Areas of potential improvements in order to make the proposed methodology competitive with established approaches for global instability analysis are discussed.

Tunnelling instability via perturbation theory

Energy Technology Data Exchange (ETDEWEB)

Graffi, S. (Bologna Univ. (Italy). Dip. di Matematica); Grecchi, V. (Moderna Univ. (Italy). Dip. di Matematica); Jona-Lasinio, G. (Paris-11 Univ., 91 - Orsay (France). Lab. de Physique Theorique et Hautes Energies)

1984-10-21

The semiclassical limit of low lying states in a multiwell potential is studied by rigorous perturbative techniques. In particular tunnelling instability and localisation of wave functions is obtained in a simple way under small deformations of symmetric potentials.

incidence and distribution of insect pests in rain-fed wheat in eastern ...

African Journals Online (AJOL)

ACSS

Insect pests are some of the major constraints limiting yield of wheat (Triticum aestivum L.) in East Africa. The objective of this study was to determine the species composition and distribution of insect pests, and their natural enemies associated with wheat in Eastern Africa. A survey was conducted in farmers' fields in ...

Resonant Drag Instabilities in protoplanetary disks: the streaming instability and new, faster-growing instabilities

Science.gov (United States)

Squire, Jonathan; Hopkins, Philip F.

2018-04-01

We identify and study a number of new, rapidly growing instabilities of dust grains in protoplanetary disks, which may be important for planetesimal formation. The study is based on the recognition that dust-gas mixtures are generically unstable to a Resonant Drag Instability (RDI), whenever the gas, absent dust, supports undamped linear modes. We show that the "streaming instability" is an RDI associated with epicyclic oscillations; this provides simple interpretations for its mechanisms and accurate analytic expressions for its growth rates and fastest-growing wavelengths. We extend this analysis to more general dust streaming motions and other waves, including buoyancy and magnetohydrodynamic oscillations, finding various new instabilities. Most importantly, we identify the disk "settling instability," which occurs as dust settles vertically into the midplane of a rotating disk. For small grains, this instability grows many orders of magnitude faster than the standard streaming instability, with a growth rate that is independent of grain size. Growth timescales for realistic dust-to-gas ratios are comparable to the disk orbital period, and the characteristic wavelengths are more than an order of magnitude larger than the streaming instability (allowing the instability to concentrate larger masses). This suggests that in the process of settling, dust will band into rings then filaments or clumps, potentially seeding dust traps, high-metallicity regions that in turn seed the streaming instability, or even overdensities that coagulate or directly collapse to planetesimals.

Marketing insects

DEFF Research Database (Denmark)

Schiemer, Carolin; Halloran, Afton Marina Szasz; Jespersen, Kristjan

2018-01-01

In entering Western markets, edible insects are typically framed as the ‘solution’ to a number of challenges caused by unsustainable global food systems, such as climate change and global health issues. In addition, some media outlets also frame insects as the next ‘superfood’. Superfood is a mar......In entering Western markets, edible insects are typically framed as the ‘solution’ to a number of challenges caused by unsustainable global food systems, such as climate change and global health issues. In addition, some media outlets also frame insects as the next ‘superfood’. Superfood...... is a marketing term for nutrient-packed foods, which are successfully promoted to Western consumers with the promises of health, well-being and beauty. However, the increase in the demand in the West is argued to cause negative social, environmental, economic and cultural consequences – externalities – felt...

Interplay between parametric instabilities in fusion - relevant laser plasmas

International Nuclear Information System (INIS)

Huller, St.

2003-01-01

The control of parametric instabilities plays an important role in laser fusion. They are driven by the incident laser beams in the underdense plasma surrounding a fusion capsule and hinder the absorption process of incident laser light which is necessary to heat the fusion target. Due to its high intensity and power, the laser light modifies the plasma density dynamically, such that two or more parametric instabilities compete, in particular stimulated Brillouin scattering and the filamentation instability. The complicated interplay between these parametric instabilities is studied in detail by developing an adequate model accompanied by numerical simulations with multidimensional codes. The model is applied to generic and to smoothed laser beams, which are necessary to limit parametric instabilities, with parameters close to experimental conditions. (author)

Flower Constancy, Insect Psychology, and Plant Evolution

Science.gov (United States)

Chittka, Lars; Thomson, James D.; Waser, Nickolas M.

Individuals of some species of pollinating insects tend to restrict their visits to only a few of the available plant species, in the process bypassing valuable food sources. The question of why this flower constancy exists is a rich and important one with implications for the organization of natural communities of plants, floral evolution, and our understanding of the learning processes involved in finding food. Some scientists have assumed that flower constancy is adaptive per se. Others argued that constancy occurs because memory capacity for floral features in insects is limited, but attempts to identify the limitations often remained rather simplistic. We elucidate now different sensory and motor memories from natural foraging tasks are stored and retrieved, using concepts from modern learning science and visual search, and conclude that flower constancy is likely to have multiple causes. Possible constraints favoring constancy are interference sensitivity of short-term memory, and temporal limitations on retrieving information from long-term memory as rapidly as from short-term memory, but further empirical evidence is needed to substantiate these possibilities. In addition, retrieving memories may be slower and more prone to errors when there are several options than when an insect copes with only a single task. In addition to memory limitations, we also point out alternative explanations for flower constancy. We then consider the way in which floral parameters, such as interplant distances, nectar rewards, flower morphology, and floral color (as seen through bees' eyes) affect constancy. Finally, we discuss the implications of pollinator constancy for plant evolution. To date there is no evidence that flowers have diverged to favor constancy, although the appropriate tests may not have yet been conducted. However, there is good evidence against the notion that pollinator constancy is involved in speciation or maintenance of plant species integrity.

Insect (food) allergy and allergens.

Science.gov (United States)

de Gier, Steffie; Verhoeckx, Kitty

2018-05-03

Insects represent an alternative for meat and fish in satisfying the increasing demand for sustainable sources of nutrition. Approximately two billion people globally consume insects. They are particularly popular in Asia, Latin America, and Africa. Most research on insect allergy has focussed on occupational or inhalation allergy. Research on insect food safety, including allergenicity, is therefore of great importance. The objective of this review is to provide an overview of cases reporting allergy following insect ingestion, studies on food allergy to insects, proteins involved in insect allergy including cross-reactive proteins, and the possibility to alter the allergenic potential of insects by food processing and digestion. Food allergy to insects has been described for silkworm, mealworm, caterpillars, Bruchus lentis, sago worm, locust, grasshopper, cicada, bee, Clanis bilineata, and the food additive carmine, which is derived from female Dactylopius coccus insects. For cockroaches, which are also edible insects, only studies on inhalation allergy have been described. Various insect allergens have been identified including tropomyosin and arginine kinase, which are both pan-allergens known for their cross-reactivity with homologous proteins in crustaceans and house dust mite. Cross-reactivity and/or co-sensitization of insect tropomyosin and arginine kinase has been demonstrated in house dust mite and seafood (e.g. prawn, shrimp) allergic patients. In addition, many other (allergenic) species (various non-edible insects, arachnids, mites, seafoods, mammals, nematoda, trematoda, plants, and fungi) have been identified with sequence alignment analysis to show potential cross-reactivity with allergens of edible insects. It was also shown that thermal processing and digestion did not eliminate insect protein allergenicity. Although purified natural allergens are scarce and yields are low, recombinant allergens from cockroach, silkworm, and Indian mealmoth are

Transverse mode coupling instability for leptons in the CERN SPS

Energy Technology Data Exchange (ETDEWEB)

Linnecar, T; Shaposhnikova, E N [European Organization for Nuclear Research, Geneva (Switzerland)

1996-08-01

The intensity of leptons accelerated in the SPS machine is limited by a vertical transverse instability. The results of measurements of the thresholds for this transverse instability are compared with theoretical predictions for different broad band impedance models of the SPS. The threshold intensities found for the transverse instability and the position of the losses in the cycle enable the parameters of the broadband resonant impedance to be specified. (author)

Eating insects

NARCIS (Netherlands)

Tan, Hui Shan Grace

2017-01-01

In recent years, edible insects have gained global attention due to their nutritional and environmental advantages over conventional meat. While numerous species of edible insects are enjoyed in various cultures around the world, most Western consumers react with disgust and aversion towards

Evolutionary conservation and changes in insect TRP channels.

Science.gov (United States)

Matsuura, Hironori; Sokabe, Takaaki; Kohno, Keigo; Tominaga, Makoto; Kadowaki, Tatsuhiko

2009-09-10

TRP (Transient Receptor Potential) channels respond to diverse stimuli and thus function as the primary integrators of varied sensory information. They are also activated by various compounds and secondary messengers to mediate cell-cell interactions as well as to detect changes in the local environment. Their physiological roles have been primarily characterized only in mice and fruit flies, and evolutionary studies are limited. To understand the evolution of insect TRP channels and the mechanisms of integrating sensory inputs in insects, we have identified and compared TRP channel genes in Drosophila melanogaster, Bombyx mori, Tribolium castaneum, Apis mellifera, Nasonia vitripennis, and Pediculus humanus genomes as part of genome sequencing efforts. All the insects examined have 2 TRPV, 1 TRPN, 1 TRPM, 3 TRPC, and 1 TRPML subfamily members, demonstrating that these channels have the ancient origins in insects. The common pattern also suggests that the mechanisms for detecting mechanical and visual stimuli and maintaining lysosomal functions may be evolutionarily well conserved in insects. However, a TRPP channel, the most ancient TRP channel, is missing in B. mori, A. mellifera, and N. vitripennis. Although P. humanus and D. melanogaster contain 4 TRPA subfamily members, the other insects have 5 TRPA subfamily members. T. castaneum, A. mellifera, and N. vitripennis contain TRPA5 channels, which have been specifically retained or gained in Coleoptera and Hymenoptera. Furthermore, TRPA1, which functions for thermotaxis in Drosophila, is missing in A. mellifera and N. vitripennis; however, they have other Hymenoptera-specific TRPA channels (AmHsTRPA and NvHsTRPA). NvHsTRPA expressed in HEK293 cells is activated by temperature increase, demonstrating that HsTRPAs function as novel thermal sensors in Hymenoptera. The total number of insect TRP family members is 13-14, approximately half that of mammalian TRP family members. As shown for mammalian TRP channels, this

Evolutionary conservation and changes in insect TRP channels

Directory of Open Access Journals (Sweden)

Tominaga Makoto

2009-09-01

Full Text Available Abstract Background TRP (Transient Receptor Potential channels respond to diverse stimuli and thus function as the primary integrators of varied sensory information. They are also activated by various compounds and secondary messengers to mediate cell-cell interactions as well as to detect changes in the local environment. Their physiological roles have been primarily characterized only in mice and fruit flies, and evolutionary studies are limited. To understand the evolution of insect TRP channels and the mechanisms of integrating sensory inputs in insects, we have identified and compared TRP channel genes in Drosophila melanogaster, Bombyx mori, Tribolium castaneum, Apis mellifera, Nasonia vitripennis, and Pediculus humanus genomes as part of genome sequencing efforts. Results All the insects examined have 2 TRPV, 1 TRPN, 1 TRPM, 3 TRPC, and 1 TRPML subfamily members, demonstrating that these channels have the ancient origins in insects. The common pattern also suggests that the mechanisms for detecting mechanical and visual stimuli and maintaining lysosomal functions may be evolutionarily well conserved in insects. However, a TRPP channel, the most ancient TRP channel, is missing in B. mori, A. mellifera, and N. vitripennis. Although P. humanus and D. melanogaster contain 4 TRPA subfamily members, the other insects have 5 TRPA subfamily members. T. castaneum, A. mellifera, and N. vitripennis contain TRPA5 channels, which have been specifically retained or gained in Coleoptera and Hymenoptera. Furthermore, TRPA1, which functions for thermotaxis in Drosophila, is missing in A. mellifera and N. vitripennis; however, they have other Hymenoptera-specific TRPA channels (AmHsTRPA and NvHsTRPA. NvHsTRPA expressed in HEK293 cells is activated by temperature increase, demonstrating that HsTRPAs function as novel thermal sensors in Hymenoptera. Conclusion The total number of insect TRP family members is 13-14, approximately half that of mammalian TRP

Insect barcode information system.

Science.gov (United States)

Pratheepa, Maria; Jalali, Sushil Kumar; Arokiaraj, Robinson Silvester; Venkatesan, Thiruvengadam; Nagesh, Mandadi; Panda, Madhusmita; Pattar, Sharath

2014-01-01

Insect Barcode Information System called as Insect Barcode Informática (IBIn) is an online database resource developed by the National Bureau of Agriculturally Important Insects, Bangalore. This database provides acquisition, storage, analysis and publication of DNA barcode records of agriculturally important insects, for researchers specifically in India and other countries. It bridges a gap in bioinformatics by integrating molecular, morphological and distribution details of agriculturally important insects. IBIn was developed using PHP/My SQL by using relational database management concept. This database is based on the client- server architecture, where many clients can access data simultaneously. IBIn is freely available on-line and is user-friendly. IBIn allows the registered users to input new information, search and view information related to DNA barcode of agriculturally important insects.This paper provides a current status of insect barcode in India and brief introduction about the database IBIn. http://www.nabg-nbaii.res.in/barcode.

A trickle instability

Science.gov (United States)

Bossa, Benjamin

2005-11-01

We address the problem of the free fall of a long, horizontal and narrow liquid layer squeezed in a vertical open Hele-Shaw cell. The layer destabilizes as it falls down, evolving into a series of liquid blobs linked together by thin bridges, which ultimately break, leaving the initially connex fluid layer as a set a disjointed drops. The mechanism of this instability is the onset of a vertical pressure gradient due to the curvature difference of the moving contact line between the advancing interface and the rear interface. This instability, whose growth rate scales with a non-trivial power of the capillary number, amplifies indifferently a broad band of wavenumbers because of the flat shape of its dispersion relation in the thin layer limit. We will finally comment on the nature of the final fragmentation process and drop size distributions.

Methods of noxious insects control by radiation on example of 'Stegobium paniceum L.'

International Nuclear Information System (INIS)

Krajewski, A.

1997-01-01

The radiation method of disinfestation on example of 'Stegobium paniceum L.' has been described. The different stadia of insect growth have been irradiated. Their radiosensitivity have been estimated on the base of dose-response relationship. Biological radiation effects have been observed as insect procreation limitation. 26 refs, 4 figs, 1 tab

Analyses of MHD instabilities

International Nuclear Information System (INIS)

Takeda, Tatsuoki

1985-01-01

In this article analyses of the MHD stabilities which govern the global behavior of a fusion plasma are described from the viewpoint of the numerical computation. First, we describe the high accuracy calculation of the MHD equilibrium and then the analysis of the linear MHD instability. The former is the basis of the stability analysis and the latter is closely related to the limiting beta value which is a very important theoretical issue of the tokamak research. To attain a stable tokamak plasma with good confinement property it is necessary to control or suppress disruptive instabilities. We, next, describe the nonlinear MHD instabilities which relate with the disruption phenomena. Lastly, we describe vectorization of the MHD codes. The above MHD codes for fusion plasma analyses are relatively simple though very time-consuming and parts of the codes which need a lot of CPU time concentrate on a small portion of the codes, moreover, the codes are usually used by the developers of the codes themselves, which make it comparatively easy to attain a high performance ratio on the vector processor. (author)

Azimuthal magnetorotational instability with super-rotation

Science.gov (United States)

Rüdiger, G.; Schultz, M.; Gellert, M.; Stefani, F.

2018-02-01

It is demonstrated that the azimuthal magnetorotational instability (AMRI) also works with radially increasing rotation rates contrary to the standard magnetorotational instability for axial fields which requires negative shear. The stability against non-axisymmetric perturbations of a conducting Taylor-Couette flow with positive shear under the influence of a toroidal magnetic field is considered if the background field between the cylinders is current free. For small magnetic Prandtl number the curves of neutral stability converge in the (Hartmann number,Reynolds number) plane approximating the stability curve obtained in the inductionless limit . The numerical solutions for indicate the existence of a lower limit of the shear rate. For large the curves scale with the magnetic Reynolds number of the outer cylinder but the flow is always stable for magnetic Prandtl number unity as is typical for double-diffusive instabilities. We are particularly interested to know the minimum Hartmann number for neutral stability. For models with resting or almost resting inner cylinder and with perfectly conducting cylinder material the minimum Hartmann number occurs for a radius ratio of \\text{in}=0.9$ . The corresponding critical Reynolds numbers are smaller than 4$ .

Sex Determination, Sex Chromosomes, and Karyotype Evolution in Insects.

Science.gov (United States)

Blackmon, Heath; Ross, Laura; Bachtrog, Doris

2017-01-01

Insects harbor a tremendous diversity of sex determining mechanisms both within and between groups. For example, in some orders such as Hymenoptera, all members are haplodiploid, whereas Diptera contain species with homomorphic as well as male and female heterogametic sex chromosome systems or paternal genome elimination. We have established a large database on karyotypes and sex chromosomes in insects, containing information on over 13000 species covering 29 orders of insects. This database constitutes a unique starting point to report phylogenetic patterns on the distribution of sex determination mechanisms, sex chromosomes, and karyotypes among insects and allows us to test general theories on the evolutionary dynamics of karyotypes, sex chromosomes, and sex determination systems in a comparative framework. Phylogenetic analysis reveals that male heterogamety is the ancestral mode of sex determination in insects, and transitions to female heterogamety are extremely rare. Many insect orders harbor species with complex sex chromosomes, and gains and losses of the sex-limited chromosome are frequent in some groups. Haplodiploidy originated several times within insects, and parthenogenesis is rare but evolves frequently. Providing a single source to electronically access data previously distributed among more than 500 articles and books will not only accelerate analyses of the assembled data, but also provide a unique resource to guide research on which taxa are likely to be informative to address specific questions, for example, for genome sequencing projects or large-scale comparative studies. © The American Genetic Association 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Residual efficacy of pyriproxyfen and Hydroprene applied to wood, metal, and concrete for control of stored-product insects

Science.gov (United States)

Pyriproxyfen and hydroprene are insect growth regulators (IGRs) that have been evaluated to control insect pests of field crops, but there are limited reports of efficacy against stored-product insects. A laboratory study was conducted to determine residual efficacy of pyriproxyfen and hydroprene on...

Phenoptosis in arthropods and immortality of social insects.

Science.gov (United States)

Kartsev, V M

2014-10-01

In general, there are no drastic differences in phenoptosis patterns in plant and animal organisms. However, there are some specific features characteristic for insects and other arthropods: 1) their development includes metamorphosis with different biochemical laws at consecutive developmental stages; 2) arthropods can reduce or stop development and aging when in a state of diapause or temporal cold immobility; 3) their life cycle often correlates with seasonal changes of surroundings; 4) polymorphism is widespread - conspecifics differ by their lifespans and phenoptosis features; 5) lifespan-related sexual dimorphism is common; 6) significant situational plasticity of life cycle organization is an important feature; for example, the German wasp (Paravespula germanica) is obligatorily univoltine in the temperate zone, while in tropical regions its lifespan increases and leads to repeated reproduction; 7) life cycles of closely related species may differ significantly, for example, in contrast to German wasp, some tropical hornets (Vespa) have only one reproduction period. Surprisingly, many insect species have been shown to be subjected to gradual aging and phenoptosis, like the highest mammals. However, queens of social insects and some long-lived arachnids can apparently be considered non-aging organisms. In some species, lifespan is limited to one season, while others live much longer or shorter. Cases of one-time reproduction are rather rare. Aphagia is common in insects (over 10,000 species). Cannibalism is an important mortality factor in insects as well as in spiders. In social insects, which exist only in colonies (families), the lifetime of a colony can be virtually unlimited. However, in case of some species the developmental cycle and death of a colony after its completion are predetermined. Most likely, natural selection in insects does not lengthen individual lifespan, but favors increase in reproduction efficiency based on fast succession of

Use of synchrotron tomography to image naturalistic anatomy in insects

Science.gov (United States)

Socha, John J.; De Carlo, Francesco

2008-08-01

Understanding the morphology of anatomical structures is a cornerstone of biology. For small animals, classical methods such as histology have provided a wealth of data, but such techniques can be problematic due to destruction of the sample. More importantly, fixation and physical slicing can cause deformation of anatomy, a critical limitation when precise three-dimensional data are required. Modern techniques such as confocal microscopy, MRI, and tabletop x-ray microCT provide effective non-invasive methods, but each of these tools each has limitations including sample size constraints, resolution limits, and difficulty visualizing soft tissue. Our research group at the Advanced Photon Source (Argonne National Laboratory) studies physiological processes in insects, focusing on the dynamics of breathing and feeding. To determine the size, shape, and relative location of internal anatomy in insects, we use synchrotron microtomography at the beamline 2-BM to image structures including tracheal tubes, muscles, and gut. Because obtaining naturalistic, undeformed anatomical information is a key component of our studies, we have developed methods to image fresh and non-fixed whole animals and tissues. Although motion artifacts remain a problem, we have successfully imaged multiple species including beetles, ants, fruit flies, and butterflies. Here we discuss advances in biological imaging and highlight key findings in insect morphology.

Teaching Rayleigh–Plateau instabilities in the laboratory

International Nuclear Information System (INIS)

Fragkopoulos, A A; Ellis, P W; Fernandez-Nieves, A

2015-01-01

The breakup of a liquid jet into spherical droplets via the Rayleigh–Plateau instability is a common and fundamental part of fluid mechanics. However, teaching this instability in a laboratory setting is challenging, requiring sophisticated methods to generate and study the jet dynamics. Recently, toroidal droplets were shown to break into one or more spherical droplets in the thin-drop limit via the Rayleigh–Plateau instability. We propose a simple experimental setup to generate toroidal droplets that break up on the order of tens of seconds, allowing for easy video capture using a basic CCD camera. With this setup, it is possible to quantify the Rayleigh–Plateau instability in a pedagogical laboratory setting. In addition, the role of curvature on jet breakup can be explored using thick toroidal droplets. We envision this setup as a powerful teaching tool for one of the most fundamental fluid dynamics processes. (paper)

Transverse two-stream instability in a matched plasma channel

International Nuclear Information System (INIS)

Whlttum, D.H.

1994-01-01

A relativistic electron beam magnetically self-focused in a plasma is subject to a transverse two stream or 'hose' instability. Linear evolution is described in terms of a tune distribution characterizing the beam, and an effective transverse impedance determined by the beam and the plasma profiles. This model is compared to cloud-in-cell simulations of three-dimensional transport of a beam with a Bennett profile, through a matched plasma channel. In the limit of large skin-depth this instability appears to be the primary limitation on stable beam transport. (author)

Using insects for STEM outreach: Development and evaluation of the UA Insect Discovery Program

Science.gov (United States)

Beal, Benjamin D.

Science and technology impact most aspects of modern daily life. It is therefore important to create a scientifically literate society. Since the majority of Americans do not take college-level science courses, strong K-12 science education is essential. At the K-5 level, however, many teachers lack the time, resources and background for effective science teaching. Elementary teachers and students may benefit from scientist-led outreach programs created by Cooperative Extension or other institutions. One example is the University of Arizona Insect Discovery Program, which provides short-duration programing that uses insects to support science content learning, teach critical thinking and spark interest in science. We conducted evaluations of the Insect Discovery programming to determine whether the activities offered were accomplishing program goals. Pre-post tests, post program questionnaires for teachers, and novel assessments of children's drawings were used as assessment tools. Assessments were complicated by the short duration of the program interactions with the children as well as their limited literacy. In spite of these difficulties, results of the pre-post tests indicated a significant impact on content knowledge and critical thinking skills. Based on post-program teacher questionnaires, positive impacts on interest in science learning were noted as much as a month after the children participated in the program. New programming and resources developed to widen the potential for impact are also described.

RNA interference: Applications and advances in insect toxicology and insect pest management.

Science.gov (United States)

Kim, Young Ho; Soumaila Issa, Moustapha; Cooper, Anastasia M W; Zhu, Kun Yan

2015-05-01

Since its discovery, RNA interference (RNAi) has revolutionized functional genomic studies due to its sequence-specific nature of post-transcriptional gene silencing. In this paper, we provide a comprehensive review of the recent literature and summarize the current knowledge and advances in the applications of RNAi technologies in the field of insect toxicology and insect pest management. Many recent studies have focused on identification and validation of the genes encoding insecticide target proteins, such as acetylcholinesterases, ion channels, Bacillus thuringiensis receptors, and other receptors in the nervous system. RNAi technologies have also been widely applied to reveal the role of genes encoding cytochrome P450 monooxygenases, carboxylesterases, and glutathione S-transferases in insecticide detoxification and resistance. More recently, studies have focused on understanding the mechanism of insecticide-mediated up-regulation of detoxification genes in insects. As RNAi has already shown great potentials for insect pest management, many recent studies have also focused on host-induced gene silencing, in which several RNAi-based transgenic plants have been developed and tested as proof of concept for insect pest management. These studies indicate that RNAi is a valuable tool to address various fundamental questions in insect toxicology and may soon become an effective strategy for insect pest management. Copyright © 2015 Elsevier Inc. All rights reserved.

Use of sterile male technique for insects to eradicate red palm weevil

International Nuclear Information System (INIS)

Al-Turaihi, E.H.

2012-01-01

The date palm plantations in the Middle East countries are infested by a devastating insect which is called red palm weevil originally from India and spread firstly into the Arab Gulf countries through imported palm trees. Red palm weevil is mainly controlled by using synthetic chemical pesticides and aggregative pheromone traps. Use of chemical pesticides has dramatically increased during recent years and posed many poisoning cases, pollution of environment, killed beneficial and non-target insects. The aim of this study is to highlight the application of Sterile Insect Technique to suppress or eradicate red palm weevil. The results revealed that the application of Sterile Insect Technique to control cotton boll weevil (Anthonomus grandis) in USA could be considered as an ideal example to apply the Sterile Insect Technique against red palm weevil because both species have similarities such as : both are exotic pests; have protected larval and pupal stages; have limited hosts; have economic importance; have an aggregative pheromone that attracts males and females; that can be used for detection and survey; and finally both insects are Coleopterans belonging to the same family.

Edible insects

NARCIS (Netherlands)

Huis, van A.

2017-01-01

Is it an impossible task to convince consumers to eat insects? This does not only apply to western consumers who are less familiar with this food habit than consumers in tropical countries. In the tropics too, many people do not consume insects, even though they are easier to collect as food than

Insects and human nutrition

DEFF Research Database (Denmark)

Roos, Nanna

2018-01-01

Despite high diversity in species as well as metamorphological life-­stages, edible insects are essentially an animal-source food contributing high quality protein and fat when viewed in the context of human nutrition. The nutritional contribution of insects to diets in populations where insects ...

Electron heat flux instabilities in the solar wind

International Nuclear Information System (INIS)

Gary, S.P.; Feldman, W.C.; Forslund, D.W.; Montgomery, M.D.

1975-01-01

There are at least three plasma instabilities associated with the electron heat flux in the solar wind. This letter reports the study of the unstable fast magnetosonic, Alfven and whistler modes via a computer code which solves the full electromagnetic, linear, Vlasov dispersion relation. Linear theory demonstrates that both the magnetosonic and Alfven instabilities are candidates for turbulent limitation of the heat flux in the solar wind at 1 A.U

Anisotropic gravitational instability

International Nuclear Information System (INIS)

Polyachenko, V.L.; Fridman, A.M.

1988-01-01

Exact solutions of stability problems are obtained for two anisotropic gravitational systems of different geometries - a layer of finite thickness at rest and a rotating cylinder of finite radius. It is shown that the anisotropic gravitational instability which develops in both cases is of Jeans type. However, in contrast to the classical aperiodic Jeans instability, this instability is oscillatory. The physics of the anisotropic gravitational instability is investigated. It is shown that in a gravitating layer this instability is due, in particular, to excitation of previously unknown interchange-Jeans modes. In the cylinder, the oscillatory Jeans instability is associated with excitation of a rotational branch, this also being responsible for the beam gravitational instability. This is the reason why this instability and the anisotropic gravitational instability have so much in common

Evolutionary Ecology of Multitrophic Interactions between Plants, Insect Herbivores and Entomopathogens.

Science.gov (United States)

Shikano, Ikkei

2017-06-01

Plants play an important role in the interactions between insect herbivores and their pathogens. Since the seminal review by Cory and Hoover (2006) on plant-mediated effects on insect-pathogen interactions, considerable progress has been made in understanding the complexity of these tritrophic interactions. Increasing interest in the areas of nutritional and ecological immunology over the last decade have revealed that plant primary and secondary metabolites can influence the outcomes of insect-pathogen interactions by altering insect immune functioning and physical barriers to pathogen entry. Some insects use plant secondary chemicals and nutrients to prevent infections (prophylactic medication) and medicate to limit the severity of infections (therapeutic medication). Recent findings suggest that there may be selectable plant traits that enhance entomopathogen efficacy, suggesting that entomopathogens could potentially impose selection pressure on plant traits that improve both pathogen and plant fitness. Moreover, plants in nature are inhabited by diverse communities of microbes, in addition to entomopathogens, some of which can trigger immune responses in insect herbivores. Plants are also shared by numerous other herbivorous arthropods with different modes of feeding that can trigger different defensive responses in plants. Some insect symbionts and gut microbes can degrade ingested defensive phytochemicals and be orally secreted onto wounded plant tissue during herbivory to alter plant defenses. Since non-entomopathogenic microbes and other arthropods are likely to influence the outcomes of plant-insect-entomopathogen interactions, I discuss a need to consider these multitrophic interactions within the greater web of species interactions.

Policosanol fabrication from insect wax and optimization by response surface methodology.

Science.gov (United States)

Ma, Jinju; Ma, Liyi; Zhang, Hong; Zhang, Zhongquan; Wang, Youqiong; Li, Kai; Chen, Xiaoming

2018-01-01

Insect wax is a famous biological resource for the role in economic production in China. Insect wax is a good source of policosanol, which may is a candidate supplement in foodstuff and pharmaceuticals that has important physiological activities. Therefore, this work aims to investigate a high-yield and rapid method for policosanol fabrication from insect wax. The conditions for policosanol fabrication were optimized as follows: an oil bath temperature of 112.7°C and reductant dosage of 0.97 g (used for the reduction of 10.00 g of insect wax). The yield of policosanol reached 83.20%, which was 4 times greater than that of existing methods, such as saponification. The total content of policosanol obtained under the optimal conditions reached 87%. In other words, a high yield of policosanol was obtained from insect wax (723.84 mg/g), that was 55 times higher than that generated from beeswax-brown via saponification. The concentrations of metal residues in policosanol were within the limits of the European Union regulations and EFSA stipulation. The LD50 values for oral doses of insect wax and policosanol were both > 5 g/kg. Policosanol was fabricated via solvent-free reduction from insect wax using LiAlH4 at a high yield. The fabrication conditions were optimized. Policosanol and insect wax showed high security, which made them potential candidates as supplements in foods, pharmaceuticals and cosmetics. The rapid and high-yield method has great potential for commercial manufacturing of policosanol.

Insect Detectives

Indian Academy of Sciences (India)

2002-08-01

Aug 1, 2002 ... all life stages of insects from and around the corpse. The collected specimens are subjected to further analysis either in the field itself or in the laboratory. A forensic entomologist has three main objectives in his mind while analyzing the insect data: determination of place, time and mode of death, each of.

Insect Keepers

Science.gov (United States)

Moore, Virginia J.; Chessin, Debby A.; Theobald, Becky

2010-01-01

Insects are fascinating creatures--especially when you and your students get up close and personal with them! To that end, the authors facilitated an inquiry-based investigation with an emphasis on identification of the different types of insects found in the school yard, their characteristics, their habitat, and what they eat, while engaging the…

Genome organization, instabilities, stem cells, and cancer

Directory of Open Access Journals (Sweden)

Senthil Kumar Pazhanisamy

2009-01-01

Full Text Available It is now widely recognized that advances in exploring genome organization provide remarkable insights on the induction and progression of chromosome abnormalities. Much of what we know about how mutations evolve and consequently transform into genome instabilities has been characterized in the spatial organization context of chromatin. Nevertheless, many underlying concepts of impact of the chromatin organization on perpetuation of multiple mutations and on propagation of chromosomal aberrations remain to be investigated in detail. Genesis of genome instabilities from accumulation of multiple mutations that drive tumorigenesis is increasingly becoming a focal theme in cancer studies. This review focuses on structural alterations evolve to raise a variety of genome instabilities that are manifested at the nucleotide, gene or sub-chromosomal, and whole chromosome level of genome. Here we explore an underlying connection between genome instability and cancer in the light of genome architecture. This review is limited to studies directed towards spatial organizational aspects of origin and propagation of aberrations into genetically unstable tumors.

Sterile insect supply, emergence, and release

International Nuclear Information System (INIS)

Dowell, R.V.; Worley, J.; Gomes, P.J.

2005-01-01

Insect mass-rearing for a sterile insect technique (SIT) programme is designed to move beyond the large-scale rearing of insects in a laboratory to the industrial production of consistently high-quality insects for sterilization and release. Each facility reflects the unique biology of the insect reared within it, but there are some generalities for all rearing facilities. Rearing insects in self-contained modules offers flexibility, and increased safety from catastrophic occurrences, compared with using a single building which houses all facets of the rearing process. Although mechanizing certain aspects of the rearing steps helps provide a consistently high-quality insect, successful mass-rearing and delivery depends largely upon the human component. Besides production in centralized facilities, insects can be produced from purchased eggs, or nowadays, adult insects are often obtained from specialized satellite emergence/collection facilities. Interest in commercializing insect production and release is increasing. Shipping sterile insects, sometimes over long distances, is now common practice. Procedures for handling and chilling adult insects, and providing food and water prior to release, are continually being improved. Sterile insects are released via static-release receptacles, ground-release systems, or most commonly from the air. The aerial release of chilled sterile insects is the most efficient method of release, especially when aircraft flight paths are guided by a Global Positioning System (GPS) linked to a computer-controlled release mechanism. (author)

Insects vis a vis radiations

International Nuclear Information System (INIS)

Srivastava, Meera

2014-01-01

Insects have turned out to be much more radiation resistant. For most insects a dose of about 500-700 Gy is required to kill them within a few weeks of exposure; although cockroaches require 900-1000 Gy. Killing insects in less than a few days requires much higher doses. These doses are for mature insects, the immature stages of some insects can be killed by doses as low as 40 Gy. Some insects can be sterilized at even lower doses, and this has application in insect control. Screw-worms, for example, can be sterilized with doses of 25-50 Gy. By contrast, doses as low as 3 Gy caused death of humans in Hiroshima and Nagasaki and doses of about 6 Gy caused death of fire fighters in the Chernobyl accident. It is not exactly certain what the basis is for the resistance of insects to ionizing radiation. It is not animal size by itself, nor lack of penetration. It is also not because of few dividing cells as these are more radiosensitive than non-dividing ones. The speculation that insects might have lower oxygen tensions, and the lack of oxygen is known to protect cells from radiation also does not work. Insect cells might have an enhanced capacity to repair radiation damage also could not be proven. The number of chromosomes influenced radio-sensitivity, and that insects had fewer chromosomes could be true. The radiation resistance is inherent to the cells, since cells derived from insects are also radiation resistant when grown in cell culture. For example, a dose of 60 Gy is required to produce a 80% kill of insect cells, while doses of 1-2 Gy are sufficient to generate this level of killing in mammalian cells. But, nevertheless, according to recent researches, radiation from Japan's leaking Fukushima nuclear plant has caused mutations in some butterflies. It is therefore clear that insects are resistant to ionizing radiation and that this resistance is an inherent property of their cells. But it is not clear exactly what the basis of this cellular resistance is

Clinical and radiological instability following standard fenestration discectomy

Directory of Open Access Journals (Sweden)

Mascarenhas Amrithlal

2009-01-01

Full Text Available Background: Post-surgical lumbar instability is an established complication but there is limited evidence in the literature regarding the incidence of lumbar instability following fenestration and discectomy. We analyzed our results following fenestration discectomy with a special focus on instability. Materials and Methods: Eighty-three patients between the age of 17 and 52 years who had undergone fenestration discectomy for a single-level lumbar intervertebral disc prolapse were followed-up for a period of 1-5 years. The criteria for instability included "instability catch,", "painful catch," and "apprehension." The working capacity of the patient and the outcome score of the surgery were assessed by means of the Oswestry disability score and the Prolo economic and functional outcome score. Flexion-extension lateral radiographs were taken and analyzed for abnormal tilt and translation. Results: Of the 83 patients included, 70 were men and 13 were women, with an average age of 37.35 years (17-52 years at 5 years follow-up. Clinical instability was seen in 10 (12.04% patients. Radiological instability was noted in 29 (34.9% patients. Only six (60% of the 10 patients who demonstrated clinical instability had radiological evidence of instability. Twenty (68.96% patients with radiological instability were asymptomatic. Three (10.34% patients with only radiological instability had unsatisfactory outcome. The Oswestry scoring showed an average score of 19.8%. Mild disability was noted in 59 (71.08% patients and moderate disability was seen in 24 (28.91% patients. None of the patients had severe disability. These outcomes were compared with the outcomes in other studies in the literature for microdiscectomy and the results were found to be comparable. Conclusion: The favorable outcome of this study is in good agreement with other studies on microdiscectomy. Clinical instability in 12.04% of the patients is in agreement with other studies. Radiological

Exploring Sound with Insects

Science.gov (United States)

Robertson, Laura; Meyer, John R.

2010-01-01

Differences in insect morphology and movement during singing provide a fascinating opportunity for students to investigate insects while learning about the characteristics of sound. In the activities described here, students use a free online computer software program to explore the songs of the major singing insects and experiment with making…

Impact of magnetic fields on the R-mode instability

International Nuclear Information System (INIS)

Rezzolla, L.

2001-01-01

The instability of r-mode oscillations in rapidly rotating neutron stars has attracted attention as a potential mechanism for producing high frequency, almost periodic gravitational waves. The analyses carried out so far have shown the existence of the instability and have considered damping by shear and bulk viscosity, as well as the interaction with a solid star crust. However, the magnetohydrodynamic coupling of the modes with a stellar magnetic field, which is likely to be present, has not been fully investigated yet. Here we discuss the relevance of a magnetic field, its modifications under the action of the r-mode instability, and how the interaction between r-mode oscillations and a magnetic field might limit the onset and duration of the instability. (author)

Radiations: tool for insect pest management

International Nuclear Information System (INIS)

Swami, Kailash Kumar; Kiradoo, M.M.; Srivastava, Meera

2012-01-01

The discovery that X-rays or gamma radiation could cause sufficient genetic damage to insect reproductive systems to induce sterility resulted from work conducted by H.J. Muller starting in the 1920s. The sterilizing effect of radiation was noted by scientists of the US Department of Agriculture who had been seeking a method to sterilize insects for many years. These scientists had theorized that if large numbers of the target insect species were reared, sterilized, and released into the field, the sterile insects would mate with the wild insects. These mating would result in no offspring and thus a decline in the population would be obtained. They calculated that if sufficient numbers of sterile insects were released, reproductive rate for the wild population would rapidly decline and reach zero. In simple language, birth control of insects. Radiation sterilization was the answer. In a SIT operation, radiation is used to sexually sterilize insects. Since the SIT is species specific, the selection the insect pest or group of pests on which to work is of primary importance. The Joint Division of the IAEA Food and Agriculture Organization (FAO) has been involved in the use of isotopes and radiation in insect control since 1964. Isotopes are used as tags or markers, for instance, of chemical molecules, insects, or plants. For example, with these tags one can follow the fate of insecticides within insects and the environment; the incorporation of nutrients into the insect; and the movements of insects under field conditions. They also can plants on which insects feed so that the quantity of consumed food can be measured and directly correlated with plant resistance. They can be used as well to follow parasites and predators of insects - for example, their movements, numbers, and ability to help control insect pests. Radiations therefore have come as a novel tool to combat insect pest problem and in future could be very helpful in various other ways, of be it be cost

Evolution of the Insects

Science.gov (United States)

Grimaldi, David; Engel, Michael S.

2005-05-01

This book chronicles the complete evolutionary history of insects--their living diversity and relationships as well as 400 million years of fossils. Introductory sections cover the living species diversity of insects, methods of reconstructing evolutionary relationships, basic insect structure, and the diverse modes of insect fossilization and major fossil deposits. Major sections then explore the relationships and evolution of each order of hexapods. The volume also chronicles major episodes in the evolutionary history of insects from their modest beginnings in the Devonian and the origin of wings hundreds of millions of years before pterosaurs and birds to the impact of mass extinctions and the explosive radiation of angiosperms on insects, and how they evolved into the most complex societies in nature. Whereas other volumes focus on either living species or fossils, this is the first comprehensive synthesis of all aspects of insect evolution. Illustrated with 955 photo- and electron- micrographs, drawings, diagrams, and field photos, many in full color and virtually all of them original, this reference will appeal to anyone engaged with insect diversity--professional entomologists and students, insect and fossil collectors, and naturalists. David Grimaldi and Michael S. Engel have collectively published over 200 scientific articles and monographs on the relationships and fossil record of insects, including 10 articles in the journals Science, Nature, and Proceedings of the National Academy of Sciences. David Grimaldi is curator in the Division of Invertebrate Zoology, American Museum of Natural History and adjunct professor at Cornell University, Columbia University, and the City University of New York. David Grimaldi has traveled in 40 countries on 6 continents, collecting and studying recent species of insects and conducting fossil excavations. He is the author of Amber: Window to the Past (Abrams, 2003). Michael S. Engel is an assistant professor in the

Efficiency Versus Instability in Plasma Accelerators

Energy Technology Data Exchange (ETDEWEB)

Lebedev, Valeri [Fermilab; Burov, Alexey [Fermilab; Nagaitsev, Sergei [Fermilab

2017-01-05

Plasma wake-field acceleration in a strongly nonlinear (a.k.a. the blowout) regime is one of the main candidates for future high-energy colliders. For this case, we derive a universal efficiency-instability relation, between the power efficiency and the key instability parameter of the witness bunch. We also show that in order to stabilize the witness bunch in a regime with high power efficiency, the bunch needs to have high energy spread, which is not presently compatible with collider-quality beam properties. It is unclear how such limitations could be overcome for high-luminosity linear colliders.

Applying the sterile insect technique to the control of insect pests

International Nuclear Information System (INIS)

LaChance, L.E.; Klassen, W.

1991-01-01

The sterile insect technique involves the mass-rearing of insects, which are sterilized by gamma rays from a 60 Co source before being released in a controlled fashion into nature. Matings between the sterile insects released and native insects produce no progeny, and so if enough of these matings occur the pest population can be controlled or even eradicated. A modification of the technique, especially suitable for the suppression of the moths and butterflies, is called the F, or inherited sterility method. In this, lower radiation doses are used such that the released males are only partially sterile (30-60%) and the females are fully sterile. When released males mate with native females some progeny are produced, but they are completely sterile. Thus, full expression of the sterility is delayed by one generation. This article describes the use of the sterile insect technique in controlling the screwworm fly, the tsetse fly, the medfly, the pink bollworm and the melon fly, and of the F 1 sterility method in the eradication of local gypsy moth infestations. 18 refs, 5 figs, 1 tab

Superconducting instabilities in the finite U Anderson lattice model

International Nuclear Information System (INIS)

Karbowski, J.

1995-01-01

We have investigated superconducting instabilities in the finite U Anderson lattice model within the Zou-Anderson slave boson representation in the Kondo lattice limit appropriate for heavy fermion systems. We found Cooper instability in the p channel and a repulsion in both the s and d channels. Based on the above mechanism of pairing, we have derived a ratio of the Gruneisen parameters Γ(T c )/Γ(T K ) which can be negative or positive, consistent with the experimental data. This result cannot be achieved in the U=∞ limit, which gives only positive values for this ratio. ((orig.))

Potentiality of botanical agents for the management of post harvest insects of maize: a review.

Science.gov (United States)

Soujanya, P Lakshmi; Sekhar, J C; Kumar, P; Sunil, N; Prasad, Ch Vara; Mallavadhani, U V

2016-05-01

Natural products derived from plants are emerging as potent biorational alternatives to synthetic insecticides for the integrated management of post harvest insects of maize. In this paper, effectiveness of botanicals including plant extracts, essential oils, their isolated pure compounds, plant based nano formulations and their mode of action against storage insects have been reviewed with special reference to maize. Plant based insecticides found to be the most promising means of controlling storage insects of maize in an eco friendly and sustainable manner. This article also throws light on the commercialization of botanicals, their limitations, challenges and future trends of storage insect management.

[Capsular retensioning in anterior unidirectional glenohumeral instability].

Science.gov (United States)

Benítez Pozos, Leonel; Martínez Molina, Oscar; Castañeda Landa, Ezequiel

2007-01-01

To present the experience of the Orthopedics Service PEMEX South Central Hospital in the management of anterior unidirectional shoulder instability with an arthroscopic technique consisting of capsular retensioning either combined with other anatomical repair procedures or alone. Thirty-one patients with anterior unidirectional shoulder instability operated-on between January 1999 and December 2005 were included. Fourteen patients underwent capsular retensioning and radiofrequency, and in 17 patients, capsular retensioning was combined with suture anchors. Patients with a history of relapsing glenohumeral dislocations and subluxations, with anterior instability with or without associated Bankart lesions were selected; all of them were young. The results were assessed considering basically the occurrence of instability during the postoperative follow-up. No cases of recurring instability occurred. Two cases had neuroma and one experienced irritation of the suture site. Six patients had residual limitation of combined lateral rotation and abduction movements, of a mean of 10 degrees compared with the healthy contralateral side. The most frequent incident was the leak of solutions to the soft tissues. Capsular retensioning, whether combined or not with other anatomical repair techniques, has proven to result in a highly satisfactory rate of glenohumeral stabilization in cases of anterior unidirectional instabilities. The arthroscopic approach offers the well-known advantages of causing less damage to the soft tissues, and a shorter time to starting rehabilitation therapy and exercises.

Insect bite reactions

Directory of Open Access Journals (Sweden)

Sanjay Singh

2013-01-01

Full Text Available Insects are a class of living creatures within the arthropods. Insect bite reactions are commonly seen in clinical practice. The present review touches upon the medically important insects and their places in the classification, the sparse literature on the epidemiology of insect bites in India, and different variables influencing the susceptibility of an individual to insect bites. Clinical features of mosquito bites, hypersensitivity to mosquito bites Epstein-Barr virus NK (HMB-EBV-NK disease, eruptive pseudoangiomatosis, Skeeter syndrome, papular pruritic eruption of HIV/AIDS, and clinical features produced by bed bugs, Mexican chicken bugs, assassin bugs, kissing bugs, fleas, black flies, Blandford flies, louse flies, tsetse flies, midges, and thrips are discussed. Brief account is presented of the immunogenic components of mosquito and bed bug saliva. Papular urticaria is discussed including its epidemiology, the 5 stages of skin reaction, the SCRATCH principle as an aid in diagnosis, and the recent evidence supporting participation of types I, III, and IV hypersensitivity reactions in its causation is summarized. Recent developments in the treatment of pediculosis capitis including spinosad 0.9% suspension, benzyl alcohol 5% lotion, dimethicone 4% lotion, isopropyl myristate 50% rinse, and other suffocants are discussed within the context of evidence derived from randomized controlled trials and key findings of a recent systematic review. We also touch upon a non-chemical treatment of head lice and the ineffectiveness of egg-loosening products. Knockdown resistance (kdr as the genetic mechanism making the lice nerves insensitive to permethrin is discussed along with the surprising contrary clinical evidence from Europe about efficacy of permethrin in children with head lice carrying kdr-like gene. The review also presents a brief account of insects as vectors of diseases and ends with discussion of prevention of insect bites and some

Treatment options for patellofemoral instability in sports traumatology

Directory of Open Access Journals (Sweden)

Philippe M. Tscholl

2013-09-01

Full Text Available Patellofemoral instability not only involves lateral patellar dislocation, patellar mal-tracking or subluxation but can also cause a limiting disability for sports activities. Its underlying causes are known as morphological anomalies of the patellofemoral joint or the mechanical axis, femorotibial malrotation, variants of the knee extensor apparatus, and ligamentous insufficiencies often accompanied by poor proprioception. Athletes with such predisposing factors are either suffering from unspecific anterior knee pain or from slightly traumatic or recurrent lateral patellar dislocation Treatment options of patellar instability are vast, and need to be tailored individually depending on the athlete’s history, age, complaints and physical demands. Different conservative and surgical treatment options are reviewed and discussed, especially limited expectations after surgery.

Kinetic simulations of Rayleigh-Taylor instabilities

International Nuclear Information System (INIS)

Sagert, Irina; Bauer, Wolfgang; Colbry, Dirk; Howell, Jim; Staber, Alec; Strother, Terrance

2014-01-01

We report on an ongoing project to develop a large scale Direct Simulation Monte Carlo code. The code is primarily aimed towards applications in astrophysics such as simulations of core-collapse supernovae. It has been tested on shock wave phenomena in the continuum limit and for matter out of equilibrium. In the current work we focus on the study of fluid instabilities. Like shock waves these are routinely used as test-cases for hydrodynamic codes and are discussed to play an important role in the explosion mechanism of core-collapse supernovae. As a first test we study the evolution of a single-mode Rayleigh-Taylor instability at the interface of a light and a heavy fluid in the presence of a gravitational acceleration. To suppress small-wavelength instabilities caused by the irregularity in the separation layer we use a large particle mean free path. The latter leads to the development of a diffusion layer as particles propagate from one fluid into the other. For small amplitudes, when the instability is in the linear regime, we compare its position and shape to the analytic prediction. Despite the broadening of the fluid interface we see a good agreement with the analytic solution. At later times we observe the development of a mushroom like shape caused by secondary Kelvin-Helmholtz instabilities as seen in hydrodynamic simulations and consistent with experimental observations.

Temporal flow instability for Magnus-Robins effect at high rotation rates

Science.gov (United States)

Sengupta, T. K.; Kasliwal, A.; de, S.; Nair, M.

2003-06-01

The lift and drag coefficients of a circular cylinder, translating and spinning at a supercritical rate is studied theoretically to explain the experimentally observed violation of maximum mean lift coefficient principle, that was proposed heuristically by Prandtl on the basis of inviscid flow model. It is also noted experimentally that flow past a rotating and translating cylinder experiences temporal instability-a fact not corroborated by any theoretical studies so far. In the present paper we report very accurate solution of Navier-Stokes equation that displays the above-mentioned instability and the violation of the maximum limit. The calculated lift coefficient exceeds the limit of /4π, instantaneously as well as in time-averaged sense. The main purpose of the present paper is to explain the observed temporal instability sequence in terms of a new theory of instability based on full Navier-Stokes equation that does not require making any assumption about the flow field, unlike other stability theories.

E-P instability in the NSNS accumulator ring

Energy Technology Data Exchange (ETDEWEB)

Ruggiero, A.G.; Blaskiewicz, M.

1997-08-01

It has been speculated that the intensity limitation observed in the Los Alamos Proton Storage Ring (PSR) is caused by a coherent instability induced by the presence of pockets of electrons generated by scattering with the molecules of the vacuum residual gas. A theoretical explanation of the e-p instability of course does exist, and is similar to the one developed for the ion-induced instability in electron storage rings. Considering the large beam power (3 MW) involved in the NSNS Accumulator Ring, and the consequences caused by even a small amount of beam loss, we need to carefully assess the effects of electrons that may be generated in the vacuum chamber.

Multi-scale responses to warming in an experimental insect metacommunity.

Science.gov (United States)

Grainger, Tess Nahanni; Gilbert, Benjamin

2017-12-01

In metacommunities, diversity is the product of species interactions at the local scale and dispersal between habitat patches at the regional scale. Although warming can alter both species interactions and dispersal, the combined effects of warming on these two processes remains uncertain. To determine the independent and interactive effects of warming-induced changes to local species interactions and dispersal, we constructed experimental metacommunities consisting of enclosed milkweed patches seeded with five herbivorous milkweed specialist insect species. We treated metacommunities with two levels of warming (unwarmed and warmed) and three levels of connectivity (isolated, low connectivity, high connectivity). Based on metabolic theory, we predicted that if plant resources were limited, warming would accelerate resource drawdown, causing local insect declines and increasing both insect dispersal and the importance of connectivity to neighboring patches for insect persistence. Conversely, given abundant resources, warming could have positive local effects on insects, and the risk of traversing a corridor to reach a neighboring patch could outweigh the benefits of additional resources. We found support for the latter scenario. Neither resource drawdown nor the weak insect-insect associations in our system were affected by warming, and most insect species did better locally in warmed conditions and had dispersal responses that were unchanged or indirectly affected by warming. Dispersal across the matrix posed a species-specific risk that led to declines in two species in connected metacommunities. Combined, this scaled up to cause an interactive effect of warming and connectivity on diversity, with unwarmed metacommunities with low connectivity incurring the most rapid declines in diversity. Overall, this study demonstrates the importance of integrating the complex outcomes of species interactions and spatial structure in understanding community response to climate

Insect anaphylaxis: addressing clinical challenges.

Science.gov (United States)

Tracy, James M; Lewis, Elena J; Demain, Jeffrey G

2011-08-01

Few allergic reactions are as potentially life-threatening, or frightening to the patient, as anaphylaxis. Food, medications, and insect stings are the three most common triggers of anaphylaxis, but insect allergy provides the best opportunity to understand the biology of anaphylaxis. If the physician can establish a diagnosis of insect allergy, treatment with nearly 98% effectiveness can be initiated. However, sometimes patients have a compelling history of insect sting anaphylaxis, but negative skin and blood tests. This situation presents us with a fascinating opportunity to understand the biology of insect anaphylaxis. Recent and ongoing work shows that occult mast cell disease may be critical in insect anaphylaxis. Mastocytosis, serum tryptase and basophil biology are key elements; genetic markers may potentially help us diagnose at-risk individuals and determine proper treatment. Understanding basophil activation may play an additional role both in diagnosis and knowing when therapy might be terminated. Mast cell disease, serum tryptase and basophil biology are providing an opportunity to better understand and manage insect allergy. This evolving understanding should improve long-term management of insect anaphylaxis and help us to better understand the clinical dilemma of appropriate management of the history-positive patient in which testing is unable to detect venom-specific IgE. Furthermore, omalizumab's immunomodulatory effects may play a role in difficult-to-treat insect allergy and mastocytosis. Finally, unrelated to these, but still important as an ongoing risk factor, is the continued underutilization of epinephrine for both acute and long-term management of insect anaphylaxis.

Environmental RNAi in herbivorous insects.

Science.gov (United States)

Ivashuta, Sergey; Zhang, Yuanji; Wiggins, B Elizabeth; Ramaseshadri, Partha; Segers, Gerrit C; Johnson, Steven; Meyer, Steve E; Kerstetter, Randy A; McNulty, Brian C; Bolognesi, Renata; Heck, Gregory R

2015-05-01

Environmental RNAi (eRNAi) is a sequence-specific regulation of endogenous gene expression in a receptive organism by exogenous double-stranded RNA (dsRNA). Although demonstrated under artificial dietary conditions and via transgenic plant presentations in several herbivorous insects, the magnitude and consequence of exogenous dsRNA uptake and the role of eRNAi remains unknown under natural insect living conditions. Our analysis of coleopteran insects sensitive to eRNAi fed on wild-type plants revealed uptake of plant endogenous long dsRNAs, but not small RNAs. Subsequently, the dsRNAs were processed into 21 nt siRNAs by insects and accumulated in high quantities in insect cells. No accumulation of host plant-derived siRNAs was observed in lepidopteran larvae that are recalcitrant to eRNAi. Stability of ingested dsRNA in coleopteran larval gut followed by uptake and transport from the gut to distal tissues appeared to be enabling factors for eRNAi. Although a relatively large number of distinct coleopteran insect-processed plant-derived siRNAs had sequence complementarity to insect transcripts, the vast majority of the siRNAs were present in relatively low abundance, and RNA-seq analysis did not detect a significant effect of plant-derived siRNAs on insect transcriptome. In summary, we observed a broad genome-wide uptake of plant endogenous dsRNA and subsequent processing of ingested dsRNA into 21 nt siRNAs in eRNAi-sensitive insects under natural feeding conditions. In addition to dsRNA stability in gut lumen and uptake, dosage of siRNAs targeting a given insect transcript is likely an important factor in order to achieve measurable eRNAi-based regulation in eRNAi-competent insects that lack an apparent silencing amplification mechanism. © 2015 Ivashuta et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

Traditional consumption of and rearing edible insects in Africa, Asia and Europe.

Science.gov (United States)

Raheem, Dele; Carrascosa, Conrado; Oluwole, Oluwatoyin Bolanle; Nieuwland, Maaike; Saraiva, Ariana; Millán, Rafael; Raposo, António

2018-02-15

The traditional consumption of edible insects is common in one third of the world's population, mostly in Latin America, Africa and Asia. There are over one thousand identified species of insects eaten in some stage of their life cycle; and they play important roles in ensuring food security. The most common way to collect insects are from the wild, which is seasonal with limited availability and has an increasing demand resulting in a disruption to the ecosystem. There is a growing interest shown in rearing insects for commercial purposes, and an industrial scale production will be required to ensure steady supplies. Industrial production will need to take into account the living environment of insects, the nutritional composition of their feed and the overall efficiency of the production system. We provide a short overview on the consumption of and rearing insects in Africa, Asia and Europe. For Africa, a snapshot is given for Nigeria, Ghana, Central African Republic, Kenya and Uganda, while the following countries are reported for Asia: China, Japan, Lao People's Democratic Republic, Thailand and Vietnam. In addition, a list of insect species with the highest potential for food and feed in the European Union is provided with some reference to The Netherlands and Finland. The review concludes that there is need to better understand the rearing and farming procedures that will yield high quality edible insects in Africa, Asia and Europe.

Nocturnal insects use optic flow for flight control.

Science.gov (United States)

Baird, Emily; Kreiss, Eva; Wcislo, William; Warrant, Eric; Dacke, Marie

2011-08-23

To avoid collisions when navigating through cluttered environments, flying insects must control their flight so that their sensory systems have time to detect obstacles and avoid them. To do this, day-active insects rely primarily on the pattern of apparent motion generated on the retina during flight (optic flow). However, many flying insects are active at night, when obtaining reliable visual information for flight control presents much more of a challenge. To assess whether nocturnal flying insects also rely on optic flow cues to control flight in dim light, we recorded flights of the nocturnal neotropical sweat bee, Megalopta genalis, flying along an experimental tunnel when: (i) the visual texture on each wall generated strong horizontal (front-to-back) optic flow cues, (ii) the texture on only one wall generated these cues, and (iii) horizontal optic flow cues were removed from both walls. We find that Megalopta increase their groundspeed when horizontal motion cues in the tunnel are reduced (conditions (ii) and (iii)). However, differences in the amount of horizontal optic flow on each wall of the tunnel (condition (ii)) do not affect the centred position of the bee within the flight tunnel. To better understand the behavioural response of Megalopta, we repeated the experiments on day-active bumble-bees (Bombus terrestris). Overall, our findings demonstrate that despite the limitations imposed by dim light, Megalopta-like their day-active relatives-rely heavily on vision to control flight, but that they use visual cues in a different manner from diurnal insects. This journal is © 2011 The Royal Society

Magnetically-Driven Convergent Instability Growth platform on Z.

Energy Technology Data Exchange (ETDEWEB)

Knapp, Patrick [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Mattsson, Thomas [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Martin, Matthew [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Benage, John F. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jenkins, James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Albright, Brian James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-09-01

Hydrodynamic instability growth is a fundamentally limiting process in many applications. In High Energy Density Physics (HEDP) systems such as inertial confinement fusion implosions and stellar explosions, hydro instabilities can dominate the evolution of the object and largely determine the final state achievable. Of particular interest is the process by which instabilities cause perturbations at a density or material interface to grow nonlinearly, introducing vorticity and eventually causing the two species to mix across the interface. Although quantifying instabilities has been the subject of many investigations in planar geometry, few have been done in converging geometry. During FY17, the team executed six convergent geometry instability experiments. Based on earlier results, the platform was redesigned and improved with respect to load centering at installation making the installation reproducible and development of a new 7.2 keV, Co He-a backlighter system to better penetrate the liner. Together, the improvements yielded significantly improved experimental results. The results in FY17 demonstrate the viability of using experiments on Z to quantify instability growth in cylindrically convergent geometry. Going forward, we will continue the partnership with staff and management at LANL to analyze the past experiments, compare to hydrodynamics growth models, and design future experiments.

Biosynthetic pathway of the phytohormone auxin in insects and screening of its inhibitors.

Science.gov (United States)

Suzuki, Hiroyoshi; Yokokura, Junpei; Ito, Tsukasa; Arai, Ryoma; Yokoyama, Chiaki; Toshima, Hiroaki; Nagata, Shinji; Asami, Tadao; Suzuki, Yoshihito

2014-10-01

Insect galls are abnormal plant tissues induced by galling insects. The galls are used for food and habitation, and the phytohormone auxin, produced by the insects, may be involved in their formation. We found that the silkworm, a non-galling insect, also produces an active form of auxin, indole-3-acetic acid (IAA), by de novo synthesis from tryptophan (Trp). A detailed metabolic analysis of IAA using IAA synthetic enzymes from silkworms indicated an IAA biosynthetic pathway composed of a three-step conversion: Trp → indole-3-acetaldoxime → indole-3-acetaldehyde (IAAld) → IAA, of which the first step is limiting IAA production. This pathway was shown to also operate in gall-inducing sawfly. Screening of a chemical library identified two compounds that showed strong inhibitory activities on the conversion step IAAld → IAA. The inhibitors can be efficiently used to demonstrate the importance of insect-synthesized auxin in gall formation in the future. Copyright © 2014 Elsevier Ltd. All rights reserved.

A Simple Flight Mill for the Study of Tethered Flight in Insects.

Science.gov (United States)

Attisano, Alfredo; Murphy, James T; Vickers, Andrew; Moore, Patricia J

2015-12-10

Flight in insects can be long-range migratory flights, intermediate-range dispersal flights, or short-range host-seeking flights. Previous studies have shown that flight mills are valuable tools for the experimental study of insect flight behavior, allowing researchers to examine how factors such as age, host plants, or population source can influence an insects' propensity to disperse. Flight mills allow researchers to measure components of flight such as speed and distance flown. Lack of detailed information about how to build such a device can make their construction appear to be prohibitively complex. We present a simple and relatively inexpensive flight mill for the study of tethered flight in insects. Experimental insects can be tethered with non-toxic adhesives and revolve around an axis by means of a very low friction magnetic bearing. The mill is designed for the study of flight in controlled conditions as it can be used inside an incubator or environmental chamber. The strongest points are the very simple electronic circuitry, the design that allows sixteen insects to fly simultaneously allowing the collection and analysis of a large number of samples in a short time and the potential to use the device in a very limited workspace. This design is extremely flexible, and we have adjusted the mill to accommodate different species of insects of various sizes.

Edible insects of Northern Angola

OpenAIRE

Lautenschläger,Thea; Neinhuis,Christoph; Monizi,Mawunu; Mandombe,José Lau; Förster,Anke; Henle,Thomas; Nuss,Matthias

2017-01-01

From 2013–2017, we accompanied and interviewed local people harvesting edible insects in the Northern Angolan province of Uíge. Insect and host plant samples were collected for species identification and nutritive analyses. Additionally, live caterpillars were taken to feed and keep until pupation and eclosion of the imago, necessary for morphological species identification. Altogether, 18 insect species eaten by humans were recorded. Twenty four edible insect species were formerly known from...

Pathogen avoidance by insect predators

OpenAIRE

Meyling, Nicolai V.; Ormond, Emma; Roy, Helen E.; Pell, Judith K.

2008-01-01

Insects can detect cues related to the risk of attack by their natural enemies. Pathogens are among the natural enemies of insects and entomopathogenic fungi attack a wide array of host species. Evidence documents that social insects in particular have adapted behavioural mechanisms to avoid infection by fungal pathogens. These mechanisms are referred to as 'behavioural resistance'. However, there is little evidence for similar adaptations in non-social insects. We have conducted experime...

Wolbachia and DNA barcoding insects: patterns, potential, and problems.

Science.gov (United States)

Smith, M Alex; Bertrand, Claudia; Crosby, Kate; Eveleigh, Eldon S; Fernandez-Triana, Jose; Fisher, Brian L; Gibbs, Jason; Hajibabaei, Mehrdad; Hallwachs, Winnie; Hind, Katharine; Hrcek, Jan; Huang, Da-Wei; Janda, Milan; Janzen, Daniel H; Li, Yanwei; Miller, Scott E; Packer, Laurence; Quicke, Donald; Ratnasingham, Sujeevan; Rodriguez, Josephine; Rougerie, Rodolphe; Shaw, Mark R; Sheffield, Cory; Stahlhut, Julie K; Steinke, Dirk; Whitfield, James; Wood, Monty; Zhou, Xin

2012-01-01

Wolbachia is a genus of bacterial endosymbionts that impacts the breeding systems of their hosts. Wolbachia can confuse the patterns of mitochondrial variation, including DNA barcodes, because it influences the pathways through which mitochondria are inherited. We examined the extent to which these endosymbionts are detected in routine DNA barcoding, assessed their impact upon the insect sequence divergence and identification accuracy, and considered the variation present in Wolbachia COI. Using both standard PCR assays (Wolbachia surface coding protein--wsp), and bacterial COI fragments we found evidence of Wolbachia in insect total genomic extracts created for DNA barcoding library construction. When >2 million insect COI trace files were examined on the Barcode of Life Datasystem (BOLD) Wolbachia COI was present in 0.16% of the cases. It is possible to generate Wolbachia COI using standard insect primers; however, that amplicon was never confused with the COI of the host. Wolbachia alleles recovered were predominantly Supergroup A and were broadly distributed geographically and phylogenetically. We conclude that the presence of the Wolbachia DNA in total genomic extracts made from insects is unlikely to compromise the accuracy of the DNA barcode library; in fact, the ability to query this DNA library (the database and the extracts) for endosymbionts is one of the ancillary benefits of such a large scale endeavor--which we provide several examples. It is our conclusion that regular assays for Wolbachia presence and type can, and should, be adopted by large scale insect barcoding initiatives. While COI is one of the five multi-locus sequence typing (MLST) genes used for categorizing Wolbachia, there is limited overlap with the eukaryotic DNA barcode region.

The portrait of eikonal instability in Lovelock theories

Energy Technology Data Exchange (ETDEWEB)

Konoplya, R.A. [Theoretical Astrophysics, Eberhard-Karls University of Tübingen, Tübingen 72076 (Germany); Zhidenko, A., E-mail: roman.konoplya@gmail.com, E-mail: olexandr.zhydenko@ufabc.edu.br [Centro de Matemática, Computação e Cognição, Universidade Federal do ABC (UFABC), Rua Abolição, CEP: 09210-180, Santo André, SP (Brazil)

2017-05-01

Perturbations and eikonal instabilities of black holes and branes in the Einstein-Gauss-Bonnet theory and its Lovelock generalization were considered in the literature for several particular cases, where the asymptotic conditions (flat, dS, AdS), the number of spacetime dimensions D , non-vanishing coupling constants (α{sub 1}, α{sub 2}, α{sub 3} etc.) and other parameters have been chosen in a specific way. Here we give a comprehensive analysis of the eikonal instabilities of black holes and branes for the most general Lovelock theory, not limited by any of the above cases. Although the part of the stability analysis is performed here purely analytically and formulated in terms of the inequalities for the black hole parameters, the most general case is treated numerically and the accurate regions of instabilities are presented. The shared Mathematica® code allows the reader to construct the regions of eikonal instability for any desired values of the parameters.

The portrait of eikonal instability in Lovelock theories

Science.gov (United States)

Konoplya, R. A.; Zhidenko, A.

2017-05-01

Perturbations and eikonal instabilities of black holes and branes in the Einstein-Gauss-Bonnet theory and its Lovelock generalization were considered in the literature for several particular cases, where the asymptotic conditions (flat, dS, AdS), the number of spacetime dimensions D, non-vanishing coupling constants (α1, α2, α3 etc.) and other parameters have been chosen in a specific way. Here we give a comprehensive analysis of the eikonal instabilities of black holes and branes for the most general Lovelock theory, not limited by any of the above cases. Although the part of the stability analysis is performed here purely analytically and formulated in terms of the inequalities for the black hole parameters, the most general case is treated numerically and the accurate regions of instabilities are presented. The shared Mathematica® code allows the reader to construct the regions of eikonal instability for any desired values of the parameters.

Review on two-phase flow instabilities in narrow spaces

International Nuclear Information System (INIS)

Tadrist, L.

2007-01-01

Instabilities in two-phase flow have been studied since the 1950s. These phenomena may appear in power generation and heat transfer systems where two-phase flow is involved. Because of thermal management in small size systems, micro-fluidics plays an important role. Typical processes must be considered when the channel hydraulic diameter becomes very small. In this paper, a brief review of two-phase flow instabilities encountered in channels having hydraulic diameters greater than 10 mm are presented. The main instability types are discussed according to the existing experimental results and models. The second part of the paper examines two-phase flow instabilities in narrow spaces. Pool and flow boiling cases are considered. Experiments as well as theoretical models existing in the literature are examined. It was found that several experimental works evidenced these instabilities meanwhile only limited theoretical developments exist in the literature. In the last part of the paper an interpretation of the two-phase flow instabilities linked to narrow spaces are presented. This approach is based on characteristic time scales of the two-phase flow and bubble growth in the capillaries

Ferromagnetic instabilities in disordered systems in the limit of strong correlations

International Nuclear Information System (INIS)

Magalhaes, A.N.; Troper, A.; Gomes, A.A.

1976-05-01

One derives the criterion for ferromagnetic instabilities in hybridized disordered systems, e.g. transition metal like systems and actinides, within the Coherent Potential Approximation (CPA), the electron-electron correlations being described by Hubbard' approximation. In the case of actinides, one treats approximately the motion of d electrons while the diagonal disorder within the f band is fully taken into account. In the case of a trnsition metal like system, except for Hubbard's approximation in dealing with d-d electron correlations, our procedure is exact within the spirit of CPA

Insect immunology and hematopoiesis.

Science.gov (United States)

Hillyer, Julián F

2016-05-01

Insects combat infection by mounting powerful immune responses that are mediated by hemocytes, the fat body, the midgut, the salivary glands and other tissues. Foreign organisms that have entered the body of an insect are recognized by the immune system when pathogen-associated molecular patterns bind host-derived pattern recognition receptors. This, in turn, activates immune signaling pathways that amplify the immune response, induce the production of factors with antimicrobial activity, and activate effector pathways. Among the immune signaling pathways are the Toll, Imd, Jak/Stat, JNK, and insulin pathways. Activation of these and other pathways leads to pathogen killing via phagocytosis, melanization, cellular encapsulation, nodulation, lysis, RNAi-mediated virus destruction, autophagy and apoptosis. This review details these and other aspects of immunity in insects, and discusses how the immune and circulatory systems have co-adapted to combat infection, how hemocyte replication and differentiation takes place (hematopoiesis), how an infection prepares an insect for a subsequent infection (immune priming), how environmental factors such as temperature and the age of the insect impact the immune response, and how social immunity protects entire groups. Finally, this review highlights some underexplored areas in the field of insect immunobiology. Copyright © 2015 Elsevier Ltd. All rights reserved.

Sterilizing insects with ionizing radiation

International Nuclear Information System (INIS)

Bakri, A.; Mehta, K.; Lance, D.R.

2005-01-01

Exposure to ionizing radiation is currently the method of choice for rendering insects reproductively sterile for area-wide integrated pest management (AW-IPM) programmes that integrate the sterile insect technique (SIT). Gamma radiation from isotopic sources (cobalt-60 or caesium-137) is most often used, but high-energy electrons and X-rays are other practical options. Insect irradiation is safe and reliable when established safety and quality-assurance guidelines are followed. The key processing parameter is absorbed dose, which must be tightly controlled to ensure that treated insects are sufficiently sterile in their reproductive cells and yet able to compete for mates with wild insects. To that end, accurate dosimetry (measurement of absorbed dose) is critical. Irradiation data generated since the 1950s, covering over 300 arthropod species, indicate that the dose needed for sterilization of arthropods varies from less than 5 Gy for blaberid cockroaches to 300 Gy or more for some arctiid and pyralid moths. Factors such as oxygen level, and insect age and stage during irradiation, and many others, influence both the absorbed dose required for sterilization and the viability of irradiated insects. Consideration of these factors in the design of irradiation protocols can help to find a balance between the sterility and competitiveness of insects produced for programmes that release sterile insects. Many programmes apply 'precautionary' radiation doses to increase the security margin of sterilization, but this overdosing often lowers competitiveness to the point where the overall induced sterility in the wild population is reduced significantly. (author)

Instabilities in inhomogeneous plasma

International Nuclear Information System (INIS)

Mikhailovsky, A.B.

1983-01-01

The plasma inhomogeneity across the magnetic field causes a wide class of instabilities which are called instabilities of an inhomogeneous plasma or gradient instabilities. The instabilities that can be studied in the approximation of a magnetic field with parallel straight field lines are treated first, followed by a discussion of the influence of shear on these instabilities. The instabilities of a weakly inhomogeneous plasma with the Maxwellian velocity distribution of particles caused by the density and temperature gradients are often called drift instabilities, and the corresponding types of perturbations are the drift waves. An elementary theory of drift instabilities is presented, based on the simplest equations of motion of particles in the field of low-frequency and long-wavelength perturbations. Following that is a more complete theory of inhomogeneous collisionless plasma instabilities which uses the permittivity tensor and, in the case of electrostatic perturbations, the scalar of permittivity. The results are used to study the instabilities of a strongly inhomogeneous plasma. The instabilities of a plasma in crossed fields are discussed and the electromagnetic instabilities of plasma with finite and high pressure are described. (Auth.)

Feedback scheme for kink instability in ERL based electron ion collider

International Nuclear Information System (INIS)

Hao, Y.; Litvinenko, V.N.; Ptitsyn, V.

2011-01-01

Kink instability presents one of the limiting factors from achieving higher luminosity in ERL based electron ion collider (EIC). However, we can take advantage of the flexibility of the linac and design a feedback system to cure the instability. This scheme raises the threshold of kink instability dramatically and provides opportunity for higher luminosity. We studied the effectiveness of this system and its dependence on the amplitude and phase of the feedback. In this paper we present results of theses studies of this scheme and describe its theoretical and practical limitations. The main advantage of an energy recovery linac (ERL) based electron ion collider (EIC) over a ring-ring type counterpart is the higher achievable luminosity. In ERL-based version, one electron beam collides with the opposing ion beam only once so that the beam-beam parameter can largely exceed the usual limitation in an electron collider ring, while the beam-beam parameter for the ion beam remains small values. The resulting luminosity may be enhanced by one order of magnitude. The beam dynamics related challenges also arise as the luminosity boost in ERL based EIC due to the significant beam-beam effect on the electron beam. The effects on the electron beam include the additional large beam-beam tune shift and nonlinear emittance growth, which are discussed. The ion beam may develop a head-tail type instability, referred as 'kink instability', through the interaction with the electron beam. In this paper, we discuss the feasibility of an active feedback system to mitigate the kink instability, by taking advantage of the flexibility of ERL. Throughout the paper, we will discuss the collision between proton and electron beam. Any other ion species can be scaled by its charge Z and ion mass A.

Eating insects

OpenAIRE

Tan, Hui Shan Grace

2017-01-01

In recent years, edible insects have gained global attention due to their nutritional and environmental advantages over conventional meat. While numerous species of edible insects are enjoyed in various cultures around the world, most Western consumers react with disgust and aversion towards eating creatures that are not regarded as food. The low consumer acceptance of this culturally inappropriate food is currently considered to be one of the key barriers to attaining the benefits of this po...

Plant–insect interactions: the role of ecological stoichiometry

Directory of Open Access Journals (Sweden)

Michał Filipiak

2017-03-01

Full Text Available The energy budget of organisms is a primary factor used to generate hypotheses in ecosystem ecology and evolutionary theory. Therefore, previous studies have focused on the energy costs and benefits of adaptations, the efficiency of energy acquisition and investment, and energy budget limitations. The maintenance of stoichiometric balance is equally important because inconsistency between the chemical composition of the consumer’s tissues and that of its food sources strongly affects the major life-history traits of the consumer and may influence the consumer’s fitness and shape plant–herbivore interactions. In this short review, the framework of ecological stoichiometry is introduced, focusing on plant–insect interactions in terrestrial ecosystems. The use of the trophic stoichiometric ratio (TSR index is presented as a useful tool for indicating the chemical elements that are scarce in food and have the potential to limit the growth and development of herbivores, thereby influencing plant – herbivorous insect interactions. As an example, the elemental composition and stoichiometry of a pollen consumer (mason bee Osmia bicornis and its preferred pollen are compared. The growth and development of O. bicornis may be colimited by the scarcity of K, Na, and N in pollen, whereas the development of the cocoon might be colimited by the scarcity of P, Mg, K, Na, Zn, Ca, and N. A literature review of the elemental composition of pollen shows high taxonomical variability in the concentrations of bee-limiting elements. The optimized collection of pollen species based on the elemental composition may represent a strategy used by bees to overcome stoichiometric mismatches, influencing their interactions with plants. It is concluded that the dependence of life-history traits on food stoichiometry should be considered when discussing life history evolution and plant–herbivore interactions. The TSR index may serve as a convenient and powerful tool

The promise of insect genomics

DEFF Research Database (Denmark)

Grimmelikhuijzen, Cornelis J P; Cazzamali, Giuseppe; Williamson, Michael

2007-01-01

Insects are the largest animal group in the world and are ecologically and economically extremely important. This importance of insects is reflected by the existence of currently 24 insect genome projects. Our perspective discusses the state-of-the-art of these genome projects and the impacts...

Kinetic instabilities in relativistic plasmas: the Harris instability revisited

International Nuclear Information System (INIS)

Tautz, R.C.

2008-01-01

Plasma instabilities that generate aperiodic fluctuations are of outstanding importance in the astrophysical context. Two prominent examples are the electromagnetic Weibel instability and the electrostatic Harris instability, which operate in initially non-magnetized and magnetized plasmas, respectively. In this talk, the original formulation of the Harris instability will be reviewed and generalizations will be presented such as the inclusion of (1) relativistic effects, (2) ion effects, and (3) mode coupling. It will be shown that, with these modifications, a powerful method has been developed for the determination of both the existence and the growth rate of low-frequency instabilities. Applications can be found in astrophysical jets, where the rest frame can be used and so no parallel motion is present. At the end of the talk, how the particle composition of gamma-ray burst jets can be predicted using the Harris technique. (author)

Carpal instability

International Nuclear Information System (INIS)

Schmitt, R.; Froehner, S.; Coblenz, G.; Christopoulos, G.

2006-01-01

This review addresses the pathoanatomical basics as well as the clinical and radiological presentation of instability patterns of the wrist. Carpal instability mostly follows an injury; however, other diseases, like CPPD arthropathy, can be associated. Instability occurs either if the carpus is unable to sustain physiologic loads (''dyskinetics'') or suffers from abnormal motion of its bones during movement (''dyskinematics''). In the classification of carpal instability, dissociative subcategories (located within proximal carpal row) are differentiated from non-dissociative subcategories (present between the carpal rows) and combined patterns. It is essential to note that the unstable wrist initially does not cause relevant signs in standard radiograms, therefore being ''occult'' for the radiologic assessment. This paper emphasizes the high utility of kinematographic studies, contrast-enhanced magnetic resonance imaging (MRI) and MR arthrography for detecting these predynamic and dynamic instability stages. Later in the natural history of carpal instability, static malalignment of the wrist and osteoarthritis will develop, both being associated with significant morbidity and disability. To prevent individual and socio-economic implications, the handsurgeon or orthopedist, as well as the radiologist, is challenged for early and precise diagnosis. (orig.)

The Native Hawaiian Insect Microbiome Initiative: A Critical Perspective for Hawaiian Insect Evolution

Directory of Open Access Journals (Sweden)

Kirsten E. Poff

2017-12-01

Full Text Available Insects associate with a diversity of microbes that can shape host ecology and diversity by providing essential biological and adaptive services. For most insect groups, the evolutionary implications of host–microbe interactions remain poorly understood. Geographically discrete areas with high biodiversity offer powerful, simplified model systems to better understand insect–microbe interactions. Hawaii boasts a diverse endemic insect fauna (~6000 species characterized by spectacular adaptive radiations. Despite this, little is known about the role of bacteria in shaping this diversity. To address this knowledge gap, we inaugurate the Native Hawaiian Insect Microbiome Initiative (NHIMI. The NHIMI is an effort intended to develop a framework for informing evolutionary and biological studies in Hawaii. To initiate this effort, we have sequenced the bacterial microbiomes of thirteen species representing iconic, endemic Hawaiian insect groups. Our results show that native Hawaiian insects associate with a diversity of bacteria that exhibit a wide phylogenetic breadth. Several groups show predictable associations with obligate microbes that permit diet specialization. Others exhibit unique ecological transitions that are correlated with shifts in their microbiomes (e.g., transition to carrion feeding from plant-feeding in Nysius wekiuicola. Finally, some groups, such as the Hawaiian Drosophila, have relatively diverse microbiomes with a conserved core of bacterial taxa across multiple species and islands.

Aquatic insect predators and mosquito control.

Science.gov (United States)

Shaalan, Essam Abdel-Salam; Canyon, Deon V

2009-12-01

Mosquitoes are serious biting pests and obligate vectors of many vertebrate pathogens. Their immature larval and pupal life stages are a common feature in most tropical and many temperate water bodies and often form a significant proportion of the biomass. Control strategies rely primarily on the use of larvicides and environmental modification to reduce recruitment and adulticides during periods of disease transmission. Larvicides are usually chemical but can involve biological toxins, agents or organisms. The use of insect predators in mosquito control has been exploited in a limited fashion and there is much room for further investigation and implementation. Insects that are recognized as having predatorial capacity with regard to mosquito prey have been identified in the Orders Odonata, Coleoptera, Diptera (primarily aquatic predators), and Hemiptera (primarily surface predators). Although their capacity is affected by certain biological and physical factors, they could play a major role in mosquito control. Furthermore, better understanding for the mosquitoes-predators relationship(s) could probably lead to satisfactory reduction of mosquito-borne diseases by utilizing either these predators in control programs, for instance biological and/or integrated control, or their kairomones as mosquitoes' ovipoisting repellents. This review covers the predation of different insect species on mosquito larvae, predator-prey-habitat relationships, co-habitation developmental issues, survival and abundance, oviposition avoidance, predatorial capacity and integrated vector control.

Insects and diseases

Science.gov (United States)

John W. Couston

2009-01-01

Insects and diseases are a natural part of forested ecosystems. Their activity is partially regulated by biotic factors, e.g., host abundance, host quality; physical factors, e.g., soil, climate; and disturbances (Berryman 1986). Insects and diseases can influence both forest patterns and forest processes by causing, for example, defoliation and mortality. These...

Protecting Yourself from Stinging Insects

Science.gov (United States)

... from St ing in g In sect s Flying Insects Outdoor workers are at risk of being stung by flying insects (bees, wasps, and hornets) and fire ants. While ... If a worker is stung by a stinging insect: ■■ Have someone stay with the worker to be ...

Low-frequency instabilities of a warm plasma in a magnetic field

International Nuclear Information System (INIS)

Smith, D.F.; Hollweg, J.V.

1977-01-01

The marginal stability of a plasma carrying current along the static magnetic field with isotropic Maxwellian ions and isotropic Maxwellian electrons drifting relative to the ions is investigated. The complete electromagnetic dispersion relation is studied using numerical techniques; the electron sums are restricted to three terms which limits the analysis to frequencies much less than the electron gyro-frequency, but includes frequencies somewhat above the ion gyro-frequency. A 'kink-like' instability and an instability of the Alfven mode are found to have the lowest threshold drift velocities in most cases. In fact the threshold drift for the kink-like instability can be significantly less than the ion thermal speed. Electrostatic and electromagnetic ion-cyclotron instabilities are also found as well as the electro-static ion-acoustic instability. No instability of the fast magnetosonic mode was found. The stability analysis provides only threshold drift velocities and gives no information about growth rates. (author)

An Integrated Molecular Database on Indian Insects.

Science.gov (United States)

Pratheepa, Maria; Venkatesan, Thiruvengadam; Gracy, Gandhi; Jalali, Sushil Kumar; Rangheswaran, Rajagopal; Antony, Jomin Cruz; Rai, Anil

2018-01-01

MOlecular Database on Indian Insects (MODII) is an online database linking several databases like Insect Pest Info, Insect Barcode Information System (IBIn), Insect Whole Genome sequence, Other Genomic Resources of National Bureau of Agricultural Insect Resources (NBAIR), Whole Genome sequencing of Honey bee viruses, Insecticide resistance gene database and Genomic tools. This database was developed with a holistic approach for collecting information about phenomic and genomic information of agriculturally important insects. This insect resource database is available online for free at http://cib.res.in. http://cib.res.in/.

Plant defense against insect herbivores

DEFF Research Database (Denmark)

Fürstenberg-Hägg, Joel; Zagrobelny, Mika; Bak, Søren

2013-01-01

, defense compounds. These bioactive specialized plant defense compounds may repel or intoxicate insects, while defense proteins often interfere with their digestion. Volatiles are released upon herbivory to repel herbivores, attract predators or for communication between leaves or plants, and to induce......Plants have been interacting with insects for several hundred million years, leading to complex defense approaches against various insect feeding strategies. Some defenses are constitutive while others are induced, although the insecticidal defense compound or protein classes are often similar...... defense responses. Plants also apply morphological features like waxes, trichomes and latices to make the feeding more difficult for the insects. Extrafloral nectar, food bodies and nesting or refuge sites are produced to accommodate and feed the predators of the herbivores. Meanwhile, herbivorous insects...

Insects: An Interdisciplinary Unit

Science.gov (United States)

Leger, Heather

2007-01-01

The author talks about an interdisciplinary unit on insects, and presents activities that can help students practice communication skills (interpersonal, interpretive, and presentational) and learn about insects with hands-on activities.

Management of Insect Sting Hypersensitivity: An Update

OpenAIRE

Pesek, Robert D.; Lockey, Richard F.

2013-01-01

Reactions to Hymenoptera insect stings are common. While most are self-limited, some induce systemic allergic reactions or anaphylaxis. Prompt recognition, diagnosis, and treatment of these reactions are important for improving quality-of-life and reducing the risk of future sting reactions. This review summarizes the current recommendations to diagnose and treat Hymenoptera sting induced allergic reactions and highlights considerations for various populations throughout the world.

Instability timescale for the inclination instability in the solar system

Science.gov (United States)

Zderic, Alexander; Madigan, Ann-Marie; Fleisig, Jacob

2018-04-01

The gravitational influence of small bodies is often neglected in the study of solar system dynamics. However, this is not always an appropriate assumption. For example, mutual secular torques between low mass particles on eccentric orbits can result in a self-gravity instability (`inclination instability'; Madigan & McCourt 2016). During the instability, inclinations increase exponentially, eccentricities decrease (detachment), and orbits cluster in argument of perihelion. In the solar system, the orbits of the most distant objects show all three of these characteristics (high inclination: Volk & Malhotra (2017), detachment: Delsanti & Jewitt (2006), and argument of perihelion clustering: Trujillo & Sheppard (2014)). The inclination instability is a natural explanation for these phenomena.Unfortunately, full N-body simulations of the solar system are unfeasible (N ≈ O(1012)), and the behavior of the instability depends on N, prohibiting the direct application of lower N simulations. Here we present the instability timescale's functional dependence on N, allowing us to extrapolate our simulation results to that appropriate for the solar system. We show that ~5 MEarth of small icy bodies in the Sedna region is sufficient for the inclination instability to occur in the outer solar system.

Insects: Bugged Out!

Science.gov (United States)

Piehl, Kathy

2011-01-01

Insects really need no introduction. They have lived on earth much longer than humans and vastly outnumber people and all other animal species combined. People encounter them daily in their houses and yards. Yet, when children want to investigate insects, books can help them start their explorations. "Paleo Bugs" carries readers back to the time…

Insect-based protein: future promising protein source for fish cultured

Science.gov (United States)

Nugroho, R. A.; Nur, F. M.

2018-04-01

As one of the vital component feed used in fisheries, fishmeal (FM) is generally added to the fish diet to enhance fish growth, digestive performance and absorption of nutrients. This addition contributes significantly to the variable production cost in the aquaculture industry. Expanded production of carnivorous species requiring high protein, high-energy feeds will further tax global fish meal. Thus, research based on the low-cost budget for feed operating cost should be strategized to assist aquaculturists in enhancing fish productivity. Moreover, suitable alternative feed ingredients will have to be utilized to provide the essential nutrients and energy needed to fuel the growth of aquaculture production. To this effect, the use of insect-based protein sources to replace FM that often scarce, expensive, limited availability, and leads to high fish production costs is alternative ways and has been gaining momentum. Currently, Insects have been proposed as one of the potential future protein sources of protein because of the production of insects is highly sustainable. Farming insects is characterized by higher food conversion efficiencies, lower environmental impact, and higher potential to be grown on waste streams.

Respiration in Aquatic Insects.

Science.gov (United States)

MacFarland, John

1985-01-01

This article: (1) explains the respiratory patterns of several freshwater insects; (2) describes the differences and mechanisms of spiracular cutaneous, and gill respiration; and (3) discusses behavioral aspects of selected aquatic insects. (ML)

Ion-Beam-Excited Electrostatic Ion Cyclotron Instability

DEFF Research Database (Denmark)

Michelsen, Poul; Pécseli, Hans; Juul Rasmussen, Jens

1977-01-01

The stability limits of the ion‐beam‐excited, electrostatic, ion cyclotron instability were investigated in a Q‐machine plasma where the electrons could be heated by microwaves. In agreement with theory, the beam energy necessary for excitation decreased with increasing electron temperature....

Ion-Beam-Excited, Electrostatic, Ion Cyclotron Instability

DEFF Research Database (Denmark)

Michelsen, Poul; Pécseli, Hans; Juul Rasmussen, Jens

1977-01-01

The stability limits of the ion‐beam‐excited, electrostatic, ion cyclotron instability were investigated in a Q‐machine plasma where the electrons could be heated by microwaves. In agreement with theory, the beam energy necessary for excitation decreased with increasing electron temperature....

Predicting the potential establishment of two insect species using the simulation environment INSIM (INsect SIMulation)

NARCIS (Netherlands)

Hemerik, Lia; Nes, van Egbert H.

2016-01-01

Degree-day models have long been used to predict events in the life cycle of insects and therewith the timing of outbreaks of insect pests and their natural enemies. This approach assumes, however, that the effect of temperature is linear, whereas developmental rates of insects are non-linearly

Strings, vortex rings, and modes of instability

Directory of Open Access Journals (Sweden)

Steven S. Gubser

2015-03-01

Full Text Available We treat string propagation and interaction in the presence of a background Neveu–Schwarz three-form field strength, suitable for describing vortex rings in a superfluid or low-viscosity normal fluid. A circular vortex ring exhibits instabilities which have been recognized for many years, but whose precise boundaries we determine for the first time analytically in the small core limit. Two circular vortices colliding head-on exhibit stronger instabilities which cause splitting into many small vortices at late times. We provide an approximate analytic treatment of these instabilities and show that the most unstable wavelength is parametrically larger than a dynamically generated length scale which in many hydrodynamic systems is close to the cutoff. We also summarize how the string construction we discuss can be derived from the Gross–Pitaevskii Lagrangian, and also how it compares to the action for giant gravitons.

Living with genome instability: the adaptation of phytoplasmas todiverse environments of their insect and plant hosts

Energy Technology Data Exchange (ETDEWEB)

Bai, Xiaodong; Zhang, Jianhua; Ewing, Adam; Miller, Sally A.; Radek, Agnes; Shevchenko, Dimitriy; Tsukerman, Kiryl; Walunas, Theresa; Lapidus, Alla; Campbell, John W.; Hogenhout Saskia A.

2006-02-17

Phytoplasmas (Candidatus Phytoplasma, Class Mollicutes) cause disease in hundreds of economically important plants, and are obligately transmitted by sap-feeding insects of the order Hemiptera, mainly leafhoppers and psyllids. The 706,569-bp chromosome and four plasmids of aster yellows phytoplasma strain witches broom (AY-WB) were sequenced and compared to the onion yellows phytoplasma strain M (OY-M) genome. The phytoplasmas have small repeat-rich genomes. The repeated DNAs are organized into large clusters, potential mobile units (PMUs), which contain tra5 insertion sequences (ISs), and specialized sigma factors and membrane proteins. So far, PMUs are unique to phytoplasmas. Compared to mycoplasmas, phytoplasmas lack several recombination and DNA modification functions, and therefore phytoplasmas probably use different mechanisms of recombination, likely involving PMUs, for the creation of variability, allowing phytoplasmas to adjust to the diverse environments of plants and insects. The irregular GC skews and presence of ISs and large repeated sequences in the AY-WB and OY-M genomes are indicative of high genomic plasticity. Nevertheless, segments of {approx}250 kb, located between genes lplA and glnQ are syntenic between the two phytoplasmas, contain the majority of the metabolic genes and no ISs. AY-WB is further along in the reductive evolution process than OY-M. The AY-WB genome is {approx}154 kb smaller than the OY-M genome, primarily as a result of fewer multicopy sequences, including PMUs. Further, AY-WB lacks genes that are truncated and are part of incomplete pathways in OY-M. This is the first comparative phytoplasma genome analysis and report of the existence of PMUs in phytoplasma genomes.

Coherent betatron instability in the Tevatron

International Nuclear Information System (INIS)

Bogacz, S.A.; Harrison, M.; Ng, K.Y.

1988-01-01

The coherent betatron instability was first observed during the recent 1987-88 Tevatron fixed target run. In this operating mode 1000 consecutive bunches are loaded into the machine at 150 GeV with a bunch spacing of 18.8 /times/ 10 -9 sec (53 MHz). The normalized transverse emittance is typically 15 π /times/ 10 -6 m rad in each plane with a longitudinal emittance of about 1.5 eV-sec. The beam is accelerated to 800 GeV in 13 sec. and then it is resonantly extracted during a 23 sec flat top. As the run progressed the bunch intensities were increased until at about 1.4 /times/ 10 10 ppb (protons per bunch) we experienced the onset of a coherent horizontal oscillation taking place in the later stages of the acceleration cycle (>600 GeV). This rapidly developing coherent instability results in a significant emittance growth, which limits machine performance and in a catastrophic scenario it even prevents extraction of the beam. In this paper we will present a simple analytic description of the observed instability. We will show that a combination of a resistive wall coupled bunch effect and a single bunch slow head-tail instability is consistent with the above observations. Finally, a systematic numerical analysis of our model (growth-time vs chromaticity plots) points to the existence of the ≥1 slow head-tail modes as a plausible mechanism for the observed coherent instability. This last claim, as mentioned before, does not have conclusive experimental evidence, although it is based on a very good agreement between the measured values of the instability growth-time and the ones calculated on the basis of our model. 4 refs., 3 figs

Insects and Bugs

Science.gov (United States)

Sutherland, Karen

2009-01-01

They have been around for centuries. They sting, they bite. They cause intense itching or painful sores. They even cause allergic reactions and sometimes death. There are two types of insects that are pests to humans--those that sting and those that bite. The insects that bite do so with their mouths and include mosquitoes, chiggers, and ticks.…

Insects as a Nitrogen Source for Plants

Directory of Open Access Journals (Sweden)

Michael J. Bidochka

2013-07-01

Full Text Available Many plants have evolved adaptations in order to survive in low nitrogen environments. One of the best-known adaptations is that of plant symbiosis with nitrogen-fixing bacteria; this is the major route by which nitrogen is incorporated into plant biomass. A portion of this plant-associated nitrogen is then lost to insects through herbivory, and insects represent a nitrogen reservoir that is generally overlooked in nitrogen cycles. In this review we show three specialized plant adaptations that allow for the recovery of insect nitrogen; that is, plants gaining nitrogen from insects. First, we show specialized adaptations by carnivorous plants in low nitrogen habitats. Insect carnivorous plants such as pitcher plants and sundews (Nepenthaceae/Sarraceniaceae and Drosera respectively are able to obtain substantial amounts of nitrogen from the insects that they capture. Secondly, numerous plants form associations with mycorrhizal fungi that can provide soluble nitrogen from the soil, some of which may be insect-derived nitrogen, obtained from decaying insects or insect frass. Finally, a specialized group of endophytic, insect-pathogenic fungi (EIPF provide host plants with insect-derived nitrogen. These soil-inhabiting fungi form a remarkable symbiosis with certain plant species. They can infect a wide range of insect hosts and also form endophytic associations in which they transfer insect-derived nitrogen to the plant. Root colonizing fungi are found in disparate fungal phylogenetic lineages, indicating possible convergent evolutionary strategies between taxa, evolution potentially driven by access to carbon-containing root exudates.

Nonlinear evolution of the lower-hybrid drift instability

International Nuclear Information System (INIS)

Brackbill, J.U.; Forslund, D.W.; Quest, K.B.; Winske, D.

1984-01-01

The results of simulations of the lower-hybrid drift instability in a neutral sheet configuration are described. The simulations use an implicit formulation to relax the usual time step limitations and thus extend previous explicit calculations to weaker gradients, larger mass ratios, and long times compared with the linear growth time. The numerical results give the scaling of the saturation level, heating rates, resistivity, and cross-field diffusion and a demonstration by comparison with a fluid electron model that dissipation in the lower-hybrid drift instability is caused by electron kinetic effects

Insect Bites and Stings

Science.gov (United States)

Most insect bites are harmless, though they sometimes cause discomfort. Bee, wasp, and hornet stings and fire ant bites usually hurt. Mosquito and flea bites usually itch. Insects can also spread diseases. In the United States, ...

The Comet assay in insects--Status, prospects and benefits for science.

Science.gov (United States)

Augustyniak, Maria; Gladysz, Marcin; Dziewięcka, Marta

2016-01-01

The Comet assay has been recently adapted to investigate DNA damage in insects. The first reports of its use in Drosophila melanogaster appeared in 2002. Since then, the interest in the application of the Comet assay to studies of insects has been rapidly increasing. Many authors see substantial potential in the use of the Comet assay in D. melanogaster for medical toxicology studies. This application could allow the testing of drugs and result in an understanding of the mechanisms of action of toxins, which could significantly influence the limited research that has been performed on vertebrates. The possible perspectives and benefits for science are considered in this review. In the last decade, the use of the Comet assay has been described in insects other than D. melanogaster. Specifically, methods to prepare a cell suspension from insect tissues, which is a difficult task, were analyzed and compared in detail. Furthermore, attention was paid to any differences and modifications in the research protocols, such as the buffer composition and electrophoresis conditions. Various scientific fields in addition to toxicological and ecotoxicological research were considered. We expect the Comet assay to be used in environmental risk assessments and to improve our understanding of many important phenomena of insect life, such as metamorphosis, molting, diapause and quiescence. The use of this method to study species that are of key importance to humans, such as pests and beneficial insects, appears to be highly probable and very promising. The use of the Comet assay for DNA stability testing in insects will most likely rapidly increase in the future. Copyright © 2015 Elsevier B.V. All rights reserved.

Importance of Resolving the Spectral Support of Beam-plasma Instabilities in Simulations

Energy Technology Data Exchange (ETDEWEB)

Shalaby, Mohamad; Broderick, Avery E. [Department of Physics and Astronomy, University of Waterloo, 200 University Avenue West, Waterloo, ON, N2L 3G1 (Canada); Chang, Philip [Department of Physics, University of Wisconsin-Milwaukee, 1900 E. Kenwood Boulevard, Milwaukee, WI 53211 (United States); Pfrommer, Christoph [Heidelberg Institute for Theoretical Studies, Schloss-Wolfsbrunnenweg 35, D-69118 Heidelberg (Germany); Lamberts, Astrid [Theoretical Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Puchwein, Ewald, E-mail: mshalaby@live.ca [Institute of Astronomy and Kavli Institute for Cosmology, University of Cambridge, Madingley Road, Cambridge, CB3 0HA (United Kingdom)

2017-10-20

Many astrophysical plasmas are prone to beam-plasma instabilities. For relativistic and dilute beams, the spectral support of the beam-plasma instabilities is narrow, i.e., the linearly unstable modes that grow with rates comparable to the maximum growth rate occupy a narrow range of wavenumbers. This places stringent requirements on the box-sizes when simulating the evolution of the instabilities. We identify the implied lower limits on the box size imposed by the longitudinal beam plasma instability, i.e., typically the most stringent condition required to correctly capture the linear evolution of the instabilities in multidimensional simulations. We find that sizes many orders of magnitude larger than the resonant wavelength are typically required. Using one-dimensional particle-in-cell simulations, we show that the failure to sufficiently resolve the spectral support of the longitudinal instability yields slower growth and lower levels of saturation, potentially leading to erroneous physical conclusion.

Importance of Resolving the Spectral Support of Beam-plasma Instabilities in Simulations

International Nuclear Information System (INIS)

Shalaby, Mohamad; Broderick, Avery E.; Chang, Philip; Pfrommer, Christoph; Lamberts, Astrid; Puchwein, Ewald

2017-01-01

Many astrophysical plasmas are prone to beam-plasma instabilities. For relativistic and dilute beams, the spectral support of the beam-plasma instabilities is narrow, i.e., the linearly unstable modes that grow with rates comparable to the maximum growth rate occupy a narrow range of wavenumbers. This places stringent requirements on the box-sizes when simulating the evolution of the instabilities. We identify the implied lower limits on the box size imposed by the longitudinal beam plasma instability, i.e., typically the most stringent condition required to correctly capture the linear evolution of the instabilities in multidimensional simulations. We find that sizes many orders of magnitude larger than the resonant wavelength are typically required. Using one-dimensional particle-in-cell simulations, we show that the failure to sufficiently resolve the spectral support of the longitudinal instability yields slower growth and lower levels of saturation, potentially leading to erroneous physical conclusion.

The Curious Connection Between Insects and Dreams.

Science.gov (United States)

Klein, Barrett A

2011-12-21

A majority of humans spend their waking hours surrounded by insects, so it should be no surprise that insects also appear in humans' dreams as we sleep. Dreaming about insects has a peculiar history, marked by our desire to explain a dream's significance and by the tactic of evoking emotions by injecting insects in dream-related works of art, film, music, and literature. I surveyed a scattered literature for examples of insects in dreams, first from the practices of dream interpretation, psychiatry, and scientific study, then from fictional writings and popular culture, and finally in the etymology of entomology by highlighting insects with dream-inspired Latinate names. A wealth of insects in dreams, as documented clinically and culturally, attests to the perceived relevance of dreams and to the ubiquity of insects in our lives.

Electromagnetic radiation from beam-plasma instabilities

International Nuclear Information System (INIS)

Stenzel, R.L.; Whelan, D.A.

1982-01-01

This chapter investigates the mechanism by which unstable electrostatic waves of an electron-beam plasma system are converted into observed electromagnetic waves. Electromagnetic radiation arises from both natural beam-plasma systems (e.g., type III solar bursts and kilometric radiation), and from man-made electron beams injected from rockets and spacecraft. A pulsed magnetized discharge plasma is produced with a 1 m diam. oxide-coated cathode and the discussed experiment is performed in the quiescent afterglow. The primary beam-plasma instability involves the excitation of electrostatic plasma waves. Electromagnetic radiation from the beam-plasma system is observed with microwave antennas outside the plasma (all probes removed) or with coax-fed dipoles which can be inserted radially and axially into the plasma. The physical process of mode coupling by which electromagnetic radiation is generated in an electrostatic beam-plasma instability is identified. The results are relevant to beam injection experiments from rockets or satellites into space plasmas. The limited penetration of the beam current into the plasma due to instabilities is demonstrated

Multiorganismal insects: diversity and function of resident microorganisms.

Science.gov (United States)

Douglas, Angela E

2015-01-07

All insects are colonized by microorganisms on the insect exoskeleton, in the gut and hemocoel, and within insect cells. The insect microbiota is generally different from microorganisms in the external environment, including ingested food. Specifically, certain microbial taxa are favored by the conditions and resources in the insect habitat, by their tolerance of insect immunity, and by specific mechanisms for their transmission. The resident microorganisms can promote insect fitness by contributing to nutrition, especially by providing essential amino acids, B vitamins, and, for fungal partners, sterols. Some microorganisms protect their insect hosts against pathogens, parasitoids, and other parasites by synthesizing specific toxins or modifying the insect immune system. Priorities for future research include elucidation of microbial contributions to detoxification, especially of plant allelochemicals in phytophagous insects, and resistance to pathogens; as well as their role in among-insect communication; and the potential value of manipulation of the microbiota to control insect pests.

The basic principles of the application of sterile insect technique for area-wide insect pest control

International Nuclear Information System (INIS)

Singgih Sutrisno

2006-01-01

Sterile Insect Technique (SIT) is a new insect pest control technique, potential, and compatible to other techniques. This technique includes irradiation of insect colony in the laboratory using gamma, n, or x-rays and then release them in the field periodically to obtain the increase of sterility probability level from the first generation to the dependence as the result the decrease of the fertility level in the field. The effect the release of sterile insects ( 9:1 ratio to the male indigenous and reproductive potential every single female of each generation reproduce 5 females ) to the insect reduction population model is conceptually discussed. From one million of the female parental decrease to be 26, 316; 1,907; 10; and 0 insects at the first, second, third, and the forth progeny respectively. Then if sterile insect technique integrated with chemical technique (insecticide) 90% kill, it will be much more effective compared to the application sterile insect technique only. From the number of one million population of insects will decrease to be 2,632; 189; and 0 insects at the first, second, and the third progeny respectively. In the Lepidoptera insects was found a phenomenon of inherited sterility. According to Knipling (1970) the inherited sterility in the first offspring caused by chromosome translocation in the gamete . In the individual of heterozygote will be die and in the homozygotes is still alive. Interspecific hybrid sterility first time was found by Laster (1972) from a cross between males Heliothis virescens (F) and females Heliothis subflexa Guenee. Male moths of the first offspring from the cross between H. virescens and H. subflexa is sterile and the females still remain fertile. If the female moths of the first offspring back crossed with male H. virescens the phenomenon of sterility always found will same situation as mention earlier the male offspring is sterile and the females is fertile ( the male F2 will be sterile and the females will

Advances on polyphenism in insects.

Science.gov (United States)

Xue, Xian-Ci; Yu, Li

2017-09-20

Polyphenism denotes that one genome produces two or more distinct phenotypes due to environmental inductions. Many cases have been reported in insects, for example, metamorphosis, seasonal polyphenism, the caste of eusocial insects and so on. Polyphenism is one of the most important reasons for insects to survive and thrive, because insects can adapt and use the environmental cues around them in order to avoid predators and reproduce by changing their phenotypes. Polyphenism has received growing attentions, ranging from the earlier description of this phenomenon to the exploration of possible inducing factors. With the recent advent of the genomic era, more and more studies based on next generation sequencing, gene knockout and RNA interference have been reported to reveal the molecular mechanism of polyphenism. In this review, we summarize the progresses of the polyphenism in insects and envision prospects of future researches.

Radioactive labelling of insects

International Nuclear Information System (INIS)

Thygesen, Th.

Experiments are described with the internal contamination of insects with phosphorus 32 introduced previously in plants of the brassica type using three different techniques. The intake of radioactivity from the plants to the insects is shown. (L.O.)

Breeding and maintaining high-quality insects

DEFF Research Database (Denmark)

Jensen, Kim; Kristensen, Torsten Nygård; Heckmann, Lars-Henrik

2017-01-01

Insects have a large potential for sustainably enhancing global food and feed production, and commercial insect production is a rising industry of high economic value. Insects suitable for production typically have fast growth, short generation time, efficient nutrient utilization, high...... reproductive potential, and thrive at high density. Insects may cost-efficiently convert agricultural and industrial food by-products into valuable protein once the technology is finetuned. However, since insect mass production is a new industry, the technology needed to efficiently farm these animals is still...... in a starting phase. Here, we discuss the challenges and precautions that need to be considered when breeding and maintaining high-quality insect populations for food and feed. This involves techniques typically used in domestic animal breeding programs including maintaining genetically healthy populations...

Consuming insects

DEFF Research Database (Denmark)

Roos, Nanna; van Huis, A.

2017-01-01

as a part of a varied diet. They also have the potential to provide bioactive compounds that have health benefits beyond simple nutritional values, as is the case for other food groups such as fruits and vegetables. Various recent studies have indicated such bioactivity in different insect species....... The enormous number of edible insect species may be a source of novel bioactive compounds with health benefits addressing global health challenges. However, any identified health benefits need to be confirmed in human studies or in standardised assays accepted in health research prior to making health claims....

Dynamical instability of a charged gaseous cylinder

Science.gov (United States)

Sharif, M.; Mumtaz, Saadia

2017-10-01

In this paper, we discuss dynamical instability of a charged dissipative cylinder under radial oscillations. For this purpose, we follow the Eulerian and Lagrangian approaches to evaluate linearized perturbed equation of motion. We formulate perturbed pressure in terms of adiabatic index by applying the conservation of baryon numbers. A variational principle is established to determine characteristic frequencies of oscillation which define stability criteria for a gaseous cylinder. We compute the ranges of radii as well as adiabatic index for both charged and uncharged cases in Newtonian and post-Newtonian limits. We conclude that dynamical instability occurs in the presence of charge if the gaseous cylinder contracts to the radius R*.

Anisotropic instability in a laser heated plasma

International Nuclear Information System (INIS)

Sangam, A.; Morreeuw, J.-P.; Tikhonchuk, V. T.

2007-01-01

The theory of the Weibel instability induced by the inverse Bremsstrahlung absorption of a laser light in an underdense plasma is revisited. It is shown that previous analyses have strongly overestimated the effect by neglecting the stabilizing term related to the interaction of the generated quasistatic magnetic field with the laser-heated electrons. The revised model leads to a reduction of the growth rate by more than a factor of 10, to strong reduction of the domain of unstable modes and to inversion of the direction of the unstable wave vectors in the long wavelength limit. The consequences of this instability on the laser plasma interaction are also discussed

The Curious Connection Between Insects and Dreams

Directory of Open Access Journals (Sweden)

Barrett A. Klein

2011-12-01

Full Text Available A majority of humans spend their waking hours surrounded by insects, so it should be no surprise that insects also appear in humans’ dreams as we sleep. Dreaming about insects has a peculiar history, marked by our desire to explain a dream’s significance and by the tactic of evoking emotions by injecting insects in dream-related works of art, film, music, and literature. I surveyed a scattered literature for examples of insects in dreams, first from the practices of dream interpretation, psychiatry, and scientific study, then from fictional writings and popular culture, and finally in the etymology of entomology by highlighting insects with dream-inspired Latinate names. A wealth of insects in dreams, as documented clinically and culturally, attests to the perceived relevance of dreams and to the ubiquity of insects in our lives.

The Curious Connection Between Insects and Dreams

Science.gov (United States)

Klein, Barrett A.

2011-01-01

A majority of humans spend their waking hours surrounded by insects, so it should be no surprise that insects also appear in humans’ dreams as we sleep. Dreaming about insects has a peculiar history, marked by our desire to explain a dream’s significance and by the tactic of evoking emotions by injecting insects in dream-related works of art, film, music, and literature. I surveyed a scattered literature for examples of insects in dreams, first from the practices of dream interpretation, psychiatry, and scientific study, then from fictional writings and popular culture, and finally in the etymology of entomology by highlighting insects with dream-inspired Latinate names. A wealth of insects in dreams, as documented clinically and culturally, attests to the perceived relevance of dreams and to the ubiquity of insects in our lives. PMID:26467945

Insects of the riparian

Science.gov (United States)

Terrence J. Rogers

1996-01-01

This paper describes life histories, defoliation problems and other activities of insects associated with forest tree species growing along high elevation streams and river banks. In addition, examples of insects and diseases associated with lower elevation riparian areas are given.

Organic farming favours insect-pollinated over non-insect pollinated forbs in meadows and wheat fields.

Science.gov (United States)

Batáry, Péter; Sutcliffe, Laura; Dormann, Carsten F; Tscharntke, Teja

2013-01-01

The aim of this study was to determine the relative effects of landscape-scale management intensity, local management intensity and edge effect on diversity patterns of insect-pollinated vs. non-insect pollinated forbs in meadows and wheat fields. Nine landscapes were selected differing in percent intensively used agricultural area (IAA), each with a pair of organic and conventional winter wheat fields and a pair of organic and conventional meadows. Within fields, forbs were surveyed at the edge and in the interior. Both diversity and cover of forbs were positively affected by organic management in meadows and wheat fields. This effect, however, differed significantly between pollination types for species richness in both agroecosystem types (i.e. wheat fields and meadows) and for cover in meadows. Thus, we show for the first time in a comprehensive analysis that insect-pollinated plants benefit more from organic management than non-insect pollinated plants regardless of agroecosystem type and landscape complexity. These benefits were more pronounced in meadows than wheat fields. Finally, the community composition of insect-pollinated and non-insect-pollinated forbs differed considerably between management types. In summary, our findings in both agroecosystem types indicate that organic management generally supports a higher species richness and cover of insect-pollinated plants, which is likely to be favourable for the density and diversity of bees and other pollinators.

Organic Farming Favours Insect-Pollinated over Non-Insect Pollinated Forbs in Meadows and Wheat Fields

Science.gov (United States)

Batáry, Péter; Sutcliffe, Laura; Dormann, Carsten F.; Tscharntke, Teja

2013-01-01

The aim of this study was to determine the relative effects of landscape-scale management intensity, local management intensity and edge effect on diversity patterns of insect-pollinated vs. non-insect pollinated forbs in meadows and wheat fields. Nine landscapes were selected differing in percent intensively used agricultural area (IAA), each with a pair of organic and conventional winter wheat fields and a pair of organic and conventional meadows. Within fields, forbs were surveyed at the edge and in the interior. Both diversity and cover of forbs were positively affected by organic management in meadows and wheat fields. This effect, however, differed significantly between pollination types for species richness in both agroecosystem types (i.e. wheat fields and meadows) and for cover in meadows. Thus, we show for the first time in a comprehensive analysis that insect-pollinated plants benefit more from organic management than non-insect pollinated plants regardless of agroecosystem type and landscape complexity. These benefits were more pronounced in meadows than wheat fields. Finally, the community composition of insect-pollinated and non-insect-pollinated forbs differed considerably between management types. In summary, our findings in both agroecosystem types indicate that organic management generally supports a higher species richness and cover of insect-pollinated plants, which is likely to be favourable for the density and diversity of bees and other pollinators. PMID:23382979

Landau Damping of Beam Instabilities by Electron Lenses

Energy Technology Data Exchange (ETDEWEB)

Shiltsev, V. [Fermilab; Alexahin, Yuri; Burov, A. [Fermilab; Valishev, A. [Fermilab

2017-06-26

Modern and future particle accelerators employ increasingly higher intensity and brighter beams of charged particles and become operationally limited by coherent beam instabilities. Usual methods to control the instabilities, such as octupole magnets, beam feedback dampers and use of chromatic effects, become less effective and insufficient. We show that, in contrast, Lorentz forces of a low-energy, a magnetically stabilized electron beam, or "electron lens", easily introduces transverse nonlinear focusing sufficient for Landau damping of transverse beam instabilities in accelerators. It is also important that, unlike other nonlinear elements, the electron lens provides the frequency spread mainly at the beam core, thus allowing much higher frequency spread without lifetime degradation. For the parameters of the Future Circular Collider, a single conventional electron lens a few meters long would provide stabilization superior to tens of thousands of superconducting octupole magnets.

Numerical simulation of Rayleigh-Taylor instability in ablation driven systems

International Nuclear Information System (INIS)

Verdon, C.P.

1984-01-01

Two-dimensional numerical simulations of ablatively accelerated thin shells subject to Rayleigh-Taylor instability are presented. Results for both single wavelength and multiwavelength perturbations show that the nonlinear effects of the instability are evident mainly in the bubble rather than the spike. Approximate roles for predicting the dominant nonlinear mode-mode interactions, which limit shell performance, are also discussed. The work concludes with a discussion of recommendations for future work in this area

40 CFR 161.590 - Nontarget insect data requirements.

Science.gov (United States)

2010-07-01

... pollinators (4) CR CR CR CR CR CR TEP TEP 141-5 Nontarget insect testing—aquatic insects Acute toxicity to aquatic insects (5) 142-1 Aquatic insect life-cycle study (5) 142-1 Simulated or actual field testing for aquatic insects (5) 142-3 Nontarget insect testing—predators and parasites (5) 143-1thru 143-3 Key: CR...

Pollination biology of fruit-bearing hedgerow plants and the role of flower-visiting insects in fruit-set.

Science.gov (United States)

Jacobs, Jennifer H; Clark, Suzanne J; Denholm, Ian; Goulson, Dave; Stoate, Chris; Osborne, Juliet L

2009-12-01

In the UK, the flowers of fruit-bearing hedgerow plants provide a succession of pollen and nectar for flower-visiting insects for much of the year. The fruits of hedgerow plants are a source of winter food for frugivorous birds on farmland. It is unclear whether recent declines in pollinator populations are likely to threaten fruit-set and hence food supply for birds. The present study investigates the pollination biology of five common hedgerow plants: blackthorn (Prunus spinosa), hawthorn (Crataegus monogyna), dog rose (Rosa canina), bramble (Rubus fruticosus) and ivy (Hedera helix). The requirement for insect pollination was investigated initially by excluding insects from flowers by using mesh bags and comparing immature and mature fruit-set with those of open-pollinated flowers. Those plants that showed a requirement for insect pollination were then tested to compare fruit-set under two additional pollination service scenarios: (1) reduced pollination, with insects excluded from flowers bagged for part of the flowering period, and (2) supplemental pollination, with flowers hand cross-pollinated to test for pollen limitation. The proportions of flowers setting fruit in blackthorn, hawthorn and ivy were significantly reduced when insects were excluded from flowers by using mesh bags, whereas fruit-set in bramble and dog rose were unaffected. Restricting the exposure of flowers to pollinators had no significant effect on fruit-set. However, blackthorn and hawthorn were found to be pollen-limited, suggesting that the pollination service was inadequate in the study area. Ensuring strong populations of insect pollinators may be essential to guarantee a winter fruit supply for birds in UK hedgerows.

Insect pests of stored grain products

International Nuclear Information System (INIS)

Chuaqui-Offermanns, N.

1987-01-01

The presence of insects in stored products is a worldwide recognized problem. In this report chemical and physical methods to control insect infestations in stored products are discussed. Special attention is given to the use of ionizing radiation to control insect pests in stored grains. The radiosensitivity of the most common insect pests at their different developmental stages is presented and discussed. The conclusions of this review are compiled in an executive summary. 62 refs

Effects of root radius, stress, crack growth and rate on fracture instability

Energy Technology Data Exchange (ETDEWEB)

McClintock, F A

1965-01-01

Of various criteria for fracture at the root of a notch, the energy, local stress, and displacement criteria have limited validity. More appropriate is the history of both stress and strain over a small region ahead of the crack, as required for fracture by the coalescence of holes. Expressions are given for crack initiation, growth, and subsequent instability in anti-plane strain of a nonhardening material. Instability is shown to depend primarily on those strain increments arising from crack growth at constant load rather than on those from increasing load at constant crack length. Thus final instability conditions are similar for single and double- ended cracks, round notches, and cracks cut under constant load. Round notches may give instability, restabilization and final instability. The growth and coalescence of holes in front of a crack in a linearly viscous material is studied for both tensile and anti-plant-strain cracks. The absence of residual strain eliminates instability, but the crack continually accelerates. (26 refs.)

Developmental instability, hybridization and heterozygosity in stick insects of the genus Bacillus (Insecta; Phasmatodea) with different modes of reproduction

DEFF Research Database (Denmark)

Andersen, D.H.; Pertoldi, C.; Loeschcke, Volker

2006-01-01

Several genetic factors are assumed to influence developmental instability (DI). One is the level of heterozygosity, with higher levels often being associated with decreased DI; another is genetic incompatibility in hybrids, which in several cases has been shown to increase DI. The genus Bacillus...

Conserved and narrow temperature limits in alpine insects: Thermal tolerance and supercooling points of the ice-crawlers, Grylloblatta (Insecta: Grylloblattodea: Grylloblattidae).

Science.gov (United States)

Schoville, Sean D; Slatyer, Rachel A; Bergdahl, James C; Valdez, Glenda A

2015-07-01

For many terrestrial species, habitat associations and range size are dependent on physiological limits, which in turn may influence large-scale patterns of species diversity. The temperature range experienced by individuals is considered to shape the breadth of the thermal niche, with species occupying temporally and/or geographically stable climates tolerating a narrow temperature range. High-elevation environments experience large temperature fluctuations, with frequent periods below 0 °C, but Grylloblatta (Grylloblattodea: Grylloblattidae) occupy climatically stable microhabitats within this region. Here we test critical thermal limits and supercooling points for five Grylloblatta populations from across a large geographic area, to examine whether the stable microhabitats of this group are associated with a narrow thermal niche and assess their capacity to tolerate cold conditions. Thermal limits are highly conserved in Grylloblatta, despite substantial genetic divergence among populations spanning 1500 m elevation and being separated by over 500 km. Further, Grylloblatta show exceptionally narrow thermal limits compared to other insect taxa with little capacity to improve cold tolerance via plasticity. In contrast, upper thermal limits were significantly depressed by cold acclimation. Grylloblatta maintain coordinated movement until they freeze, and they die upon freezing. Convergence of the critical thermal minima, supercooling point and lower lethal limits point to adaptation to a cold but, importantly, constant thermal environment. These physiological data provide an explanation for the high endemism and patchy distribution of Grylloblatta, which relies on subterranean retreats to accommodate narrow thermal limits. These retreats are currently buffered from temperature fluctuations by snow cover, and a declining snowpack thus places Grylloblatta at risk of exposure to temperatures beyond its tolerance capacity. Copyright © 2015 Elsevier Ltd. All rights

RNAi Technology for Insect Management and Protection of Beneficial Insects from Diseases: Lessons, Challenges and Risk Assessments.

Science.gov (United States)

Zotti, M J; Smagghe, G

2015-06-01

The time has passed for us to wonder whether RNA interference (RNAi) effectively controls pest insects or protects beneficial insects from diseases. The RNAi era in insect science began with studies of gene function and genetics that paved the way for the development of novel and highly specific approaches for the management of pest insects and, more recently, for the treatment and prevention of diseases in beneficial insects. The slight differences in components of RNAi pathways are sufficient to provide a high degree of variation in responsiveness among insects. The current framework to assess the negative effects of genetically modified (GM) plants on human health is adequate for RNAi-based GM plants. Because of the mode of action of RNAi and the lack of genomic data for most exposed non-target organisms, it becomes difficult to determine the environmental risks posed by RNAi-based technologies and the benefits provided for the protection of crops. A better understanding of the mechanisms that determine the variability in the sensitivity of insects would accelerate the worldwide release of commercial RNAi-based approaches.

Agricultural production - Phase 2. Indonesia. Insect ecology studies and insect pest control

International Nuclear Information System (INIS)

Butt, B.

1992-01-01

This document reviews the activities of the Pest Control Research Group in Indonesia. Pests under study are the diamondback moth (Plutella xylostella), the rice stem borer (Chilo suppressalis), the sugar cane borer (Chilo auricilius), bean flies (Agromyza spp.), tobacco insects (Heliothis armigera and Spodoptera litura) and cotton insects, especially the pink bollworm

Potential applications of insect symbionts in biotechnology.

Science.gov (United States)

Berasategui, Aileen; Shukla, Shantanu; Salem, Hassan; Kaltenpoth, Martin

2016-02-01

Symbiotic interactions between insects and microorganisms are widespread in nature and are often the source of ecological innovations. In addition to supplementing their host with essential nutrients, microbial symbionts can produce enzymes that help degrade their food source as well as small molecules that defend against pathogens, parasites, and predators. As such, the study of insect ecology and symbiosis represents an important source of chemical compounds and enzymes with potential biotechnological value. In addition, the knowledge on insect symbiosis can provide novel avenues for the control of agricultural pest insects and vectors of human diseases, through targeted manipulation of the symbionts or the host-symbiont associations. Here, we discuss different insect-microbe interactions that can be exploited for insect pest and human disease control, as well as in human medicine and industrial processes. Our aim is to raise awareness that insect symbionts can be interesting sources of biotechnological applications and that knowledge on insect ecology can guide targeted efforts to discover microorganisms of applied value.

21 CFR 1250.95 - Insect control.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Insect control. 1250.95 Section 1250.95 Food and... SANITATION Sanitation Facilities and Conditions on Vessels § 1250.95 Insect control. Vessels shall be... generally accepted methods of insect control. ...

Age and size at maturity: a quantitative review of diet-induced reaction norms in insects.

Science.gov (United States)

Teder, Tiit; Vellau, Helen; Tammaru, Toomas

2014-11-01

Optimality models predict that diet-induced bivariate reaction norms for age and size at maturity can have diverse shapes, with the slope varying from negative to positive. To evaluate these predictions, we perform a quantitative review of relevant data, using a literature-derived database of body sizes and development times for over 200 insect species. We show that bivariate reaction norms with a negative slope prevail in nearly all taxonomic and ecological categories of insects as well as in some other ectotherm taxa with comparable life histories (arachnids and amphibians). In insects, positive slopes are largely limited to species, which feed on discrete resource items, parasitoids in particular. By contrast, with virtually no meaningful exceptions, herbivorous and predatory insects display reaction norms with a negative slope. This is consistent with the idea that predictable resource depletion, a scenario selecting for positively sloped reaction norms, is not frequent for these insects. Another source of such selection-a positive correlation between resource levels and juvenile mortality rates-should similarly be rare among insects. Positive slopes can also be predicted by models which integrate life-history evolution and population dynamics. As bottom-up regulation is not common in most insect groups, such models may not be most appropriate for insects. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

Herbivory increases diversification across insect clades.

Science.gov (United States)

Wiens, John J; Lapoint, Richard T; Whiteman, Noah K

2015-09-24

Insects contain more than half of all living species, but the causes of their remarkable diversity remain poorly understood. Many authors have suggested that herbivory has accelerated diversification in many insect clades. However, others have questioned the role of herbivory in insect diversification. Here, we test the relationships between herbivory and insect diversification across multiple scales. We find a strong, positive relationship between herbivory and diversification among insect orders. However, herbivory explains less variation in diversification within some orders (Diptera, Hemiptera) or shows no significant relationship with diversification in others (Coleoptera, Hymenoptera, Orthoptera). Thus, we support the overall importance of herbivory for insect diversification, but also show that its impacts can vary across scales and clades. In summary, our results illuminate the causes of species richness patterns in a group containing most living species, and show the importance of ecological impacts on diversification in explaining the diversity of life.

Insect Gallers and Their Plant Hosts: From Omics Data to Systems Biology

Directory of Open Access Journals (Sweden)

Caryn N. Oates

2016-11-01

Full Text Available Gall-inducing insects are capable of exerting a high level of control over their hosts’ cellular machinery to the extent that the plant’s development, metabolism, chemistry, and physiology are all altered in favour of the insect. Many gallers are devastating pests in global agriculture and the limited understanding of their relationship with their hosts prevents the development of robust management strategies. Omics technologies are proving to be important tools in elucidating the mechanisms involved in the interaction as they facilitate analysis of plant hosts and insect effectors for which little or no prior knowledge exists. In this review, we examine the mechanisms behind insect gall development using evidence from omics-level approaches. The secretion of effector proteins and induced phytohormonal imbalances are highlighted as likely mechanisms involved in gall development. However, understanding how these components function within the system is far from complete and a number of questions need to be answered before this information can be used in the development of strategies to engineer or breed plants with enhanced resistance.

Hydrodynamic instabilities in inertial fusion

International Nuclear Information System (INIS)

Hoffman, N.M.

1994-01-01

This report discusses topics on hydrodynamics instabilities in inertial confinement: linear analysis of Rayleigh-Taylor instability; ablation-surface instability; bubble rise in late-stage Rayleigh-Taylor instability; and saturation and multimode interactions in intermediate-stage Rayleigh-Taylor instability

Beneficial Insects: Beetles

OpenAIRE

Hodgson, Erin W.; Patterson, Ron

2007-01-01

There are many beneficial beetles in Utah besides lady beetles or ladybugs. Beetles can significantly reduce common insect and weed problems and in some cases eliminate the need for chemical control. Examples of beneficial beetles include: ground beetles, rove beetles, tiger beetles and tortoise beetles. Many of these beetles are native to Utah, while others have been purposely introduced to help control damage from exotic insect and weed pests.

Insect Capital

Directory of Open Access Journals (Sweden)

Andrew Pilsch

2015-12-01

Full Text Available In this note, Pilsch address William Gibson’s use of insect imagery in to trouble the common understanding of the novel Neuromancer, its commentary on corporate culture, and its relationship to a then-emergent posthumanism. Further, he concludes by suggesting that, for Gibson, the insect hive as an image for the corporate body shows that corporate culture is, in contrast to the banal image the term brings to mind, a set of nefarious cultural techniques derived for interfacing human bodies with the corporation’s native environment in the postmodern era: the abstractions of data.

Insect Peptides - Perspectives in Human Diseases Treatment.

Science.gov (United States)

Chowanski, Szymon; Adamski, Zbigniew; Lubawy, Jan; Marciniak, Pawel; Pacholska-Bogalska, Joanna; Slocinska, Malgorzata; Spochacz, Marta; Szymczak, Monika; Urbanski, Arkadiusz; Walkowiak-Nowicka, Karolina; Rosinski, Grzegorz

2017-01-01

Insects are the largest and the most widely distributed group of animals in the world. Their diversity is a source of incredible variety of different mechanisms of life processes regulation. There are many agents that regulate immunology, reproduction, growth and development or metabolism. Hence, it seems that insects may be a source of numerous substances useful in human diseases treatment. Especially important in the regulation of insect physiology are peptides, like neuropeptides, peptide hormones or antimicrobial peptides. There are two main aspects where they can be helpful, 1) Peptides isolated from insects may become potential drugs in therapy of different diseases, 2) A lot of insect peptide hormones show structural or functional homology to mammalian peptide hormones and the comparative studies may give a new look on human disorders. In our review we focused on three group of insect derived peptides: 1) immune-active peptides, 2) peptide hormones and 3) peptides present in venoms. In our review we try to show the considerable potential of insect peptides in searching for new solutions for mammalian diseases treatment. We summarise the knowledge about properties of insect peptides against different virulent agents, anti-inflammatory or anti-nociceptive properties as well as compare insect and mammalian/vertebrate peptide endocrine system to indicate usefulness of knowledge about insect peptide hormones in drug design. The field of possible using of insect delivered peptide to therapy of various human diseases is still not sufficiently explored. Undoubtedly, more attention should be paid to insects due to searching new drugs. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Dynamical instabilities in magnetohydrodynamic wind-cloud interactions

Science.gov (United States)

Banda-Barragan, Wladimir Eduardo; Parkin, Elliot Ross; Crocker, Roland M.; Federrath, Christoph; Bicknell, Geoffrey Vincent

2015-08-01

We report the results from a comprehensive numerical study that investigates the role of dynamical instabilities in magnetohydrodynamic interactions between winds and spherical clouds in the interstellar medium. The growth of Kelvin-Helmholtz (KH) and Rayleigh-Taylor (RT) instabilities at interfaces between wind and cloud material is responsible for the disruption of clouds and the formation of filamentary tails. We show how different strengths and orientations of the initial magnetic field affect the development of unstable modes and the ultimate morphology of these filaments. In the weak field limit, for example, KH instabilities developing at the flanks of clouds are dominant, whilst they are suppressed when stronger fields are considered. On the other hand, perturbations that originate RT instabilities at the leading edge of clouds are enhanced when fields are locally stronger. The orientation of the field lines also plays an important role in the structure of filaments. Magnetic ropes are key features of systems in which fields are aligned with the wind velocity, whilst current sheets are favoured when the initial field is preferentially transverse to the wind velocity. We compare our findings with analytical predictions obtained from the linear theory of hydromagnetic stability and provide a classification of filamentary tails based on their morphology.

Aquatic Insects and their Potential to Contribute to the Diet of the Globally Expanding Human Population.

Science.gov (United States)

Williams, D Dudley; Williams, Siân S

2017-07-21

Of the 30 extant orders of true insect, 12 are considered to be aquatic, or semiaquatic, in either some or all of their life stages. Out of these, six orders contain species engaged in entomophagy, but very few are being harvested effectively, leading to over-exploitation and local extinction. Examples of existing practices are given, ranging from the extremes of including insects (e.g., dipterans) in the dietary cores of many indigenous peoples to consumption of selected insects, by a wealthy few, as novelty food (e.g., caddisflies). The comparative nutritional worth of aquatic insects to the human diet and to domestic animal feed is examined. Questions are raised as to whether natural populations of aquatic insects can yield sufficient biomass to be of practicable and sustained use, whether some species can be brought into high-yield cultivation, and what are the requirements and limitations involved in achieving this?

Aquatic Insects and their Potential to Contribute to the Diet of the Globally Expanding Human Population

Science.gov (United States)

Williams, D. Dudley; Williams, Siân S.

2017-01-01

Of the 30 extant orders of true insect, 12 are considered to be aquatic, or semiaquatic, in either some or all of their life stages. Out of these, six orders contain species engaged in entomophagy, but very few are being harvested effectively, leading to over-exploitation and local extinction. Examples of existing practices are given, ranging from the extremes of including insects (e.g., dipterans) in the dietary cores of many indigenous peoples to consumption of selected insects, by a wealthy few, as novelty food (e.g., caddisflies). The comparative nutritional worth of aquatic insects to the human diet and to domestic animal feed is examined. Questions are raised as to whether natural populations of aquatic insects can yield sufficient biomass to be of practicable and sustained use, whether some species can be brought into high-yield cultivation, and what are the requirements and limitations involved in achieving this? PMID:28754025

Insects, isotopes and radiations

International Nuclear Information System (INIS)

Lingkvist, D.A.

1987-01-01

The IAEA activity on coordinating the IAEA member-state efforts in the field of pest control is considered. A complex program of agricultural pest control (IPM), applied in many parts of the world is developed. The program provides for the use of natural means of control and cases of critical pest numbers-the use of insecticides. When controlling certain types of insects it is advisable to apply the 'large area control' methods which provide for the insect destruction in places of their concentration prior to migration. Methods of pest control over large areas also include radiation sexual sterilization method (SSM), application of insect phoromons (sexual attractants) to prevent mating, other types of chemical attractants, traps, mass cultivation and reproduction of parasite plants and animals, destroying insects, as well as improvement of host-plant resistance. A great attention is paid to isotope and radiation application in pest control (labelling, sexual sterilization using ionising radiation, radiation application in genetic engineering, mutant plant cultivation)

An experimental platform for generating Richtmyer-Meshkov instabilities on Z.

Energy Technology Data Exchange (ETDEWEB)

Harding, Eric; Martin, Matthew

2013-04-01

The Richtmyer-Meshkov (RM) instability results when a shock wave crosses a rippled interface between two different materials. The shock deposited vorticity causes the ripples to grow into long spikes. Ultimately this process encourages mixing in many warm dense matter and plasma flows of interest. However, generating pure RM instabilities from initially solid targets is difficult because longlived, steady shocks are required. As a result only a few relevant experiments exist, and current theoretical understanding is limited. Here we propose using a flyer-plate driven target to generate RM instabilities with the Z machine. The target consists of a Be impact layer with sinusoidal perturbations and is followed by a low-density carbon foam. Simulation results show that the RM instability grows for 60 ns before release waves reach the perturbation. This long drive time makes Z uniquely suited for generating the high-quality data that is needed by the community.

Attention-like processes in insects.

Science.gov (United States)

Nityananda, Vivek

2016-11-16

Attention is fundamentally important for sensory systems to focus on behaviourally relevant stimuli. It has therefore been an important field of study in human psychology and neuroscience. Primates, however, are not the only animals that might benefit from attention-like processes. Other animals, including insects, also have to use their senses and select one among many stimuli to forage, avoid predators and find mates. They have evolved different mechanisms to reduce the information processed by their brains to focus on only relevant stimuli. What are the mechanisms used by insects to selectively attend to visual and auditory stimuli? Do these attention-like mechanisms achieve the same functions as they do in primates? To investigate these questions, I use an established framework for investigating attention in non-human animals that proposes four fundamental components of attention: salience filters, competitive selection, top-down sensitivity control and working memory. I discuss evidence for each of these component processes in insects and compare the characteristics of these processes in insects to what we know from primates. Finally, I highlight important outstanding questions about insect attention that need to be addressed for us to understand the differences and similarities between vertebrate and insect attention. © 2016 The Author(s).

Plant responses to insect egg deposition

NARCIS (Netherlands)

Hilker, M.; Fatouros, N.E.

2015-01-01

Plants can respond to insect egg deposition and thus resist attack by herbivorous insects from the beginning of the attack, egg deposition. We review ecological effects of plant responses to insect eggs and differentiate between egg-induced plant defenses that directly harm the eggs and indirect

Evaluation of hazardous chemicals in edible insects and insect-based food intended for human consumption.

Science.gov (United States)

Poma, Giulia; Cuykx, Matthias; Amato, Elvio; Calaprice, Chiara; Focant, Jean Francois; Covaci, Adrian

2017-02-01

Due to the rapid increase in world population, the waste of food and resources, and non-sustainable food production practices, the use of alternative food sources is currently strongly promoted. In this perspective, insects may represent a valuable alternative to main animal food sources due to their nutritional value and sustainable production. However, edible insects may be perceived as an unappealing food source and are indeed rarely consumed in developed countries. The food safety of edible insects can thus contribute to the process of acceptance of insects as an alternative food source, changing the perception of developed countries regarding entomophagy. In the present study, the levels of organic contaminants (i.e. flame retardants, PCBs, DDT, dioxin compounds, pesticides) and metals (As, Cd, Co, Cr, Cu, Ni, Pb, Sn, Zn) were investigated in composite samples of several species of edible insects (greater wax moth, migratory locust, mealworm beetle, buffalo worm) and four insect-based food items currently commercialized in Belgium. The organic chemical mass fractions were relatively low (PCBs: 27-2065 pg/g ww; OCPs: 46-368 pg/g ww; BFRs: up to 36 pg/g ww; PFRs 783-23800 pg/g ww; dioxin compounds: up to 0.25 pg WHO-TEQ/g ww) and were generally lower than those measured in common animal products. The untargeted screening analysis revealed the presence of vinyltoluene, tributylphosphate (present in 75% of the samples), and pirimiphos-methyl (identified in 50% of the samples). The levels of Cu and Zn in insects were similar to those measured in meat and fish in other studies, whereas As, Co, Cr, Pb, Sn levels were relatively low in all samples (consume these insect species with no additional hazards in comparison to the more commonly consumed animal products. Copyright © 2016 Elsevier Ltd. All rights reserved.

Tertiary instability of zonal flows within the Wigner-Moyal formulation of drift turbulence

Science.gov (United States)

Zhu, Hongxuan; Ruiz, D. E.; Dodin, I. Y.

2017-10-01

The stability of zonal flows (ZFs) is analyzed within the generalized-Hasegawa-Mima model. The necessary and sufficient condition for a ZF instability, which is also known as the tertiary instability, is identified. The qualitative physics behind the tertiary instability is explained using the recently developed Wigner-Moyal formulation and the corresponding wave kinetic equation (WKE) in the geometrical-optics (GO) limit. By analyzing the drifton phase space trajectories, we find that the corrections proposed in Ref. to the WKE are critical for capturing the spatial scales characteristic for the tertiary instability. That said, we also find that this instability itself cannot be adequately described within a GO formulation in principle. Using the Wigner-Moyal equations, which capture diffraction, we analytically derive the tertiary-instability growth rate and compare it with numerical simulations. The research was sponsored by the U.S. Department of Energy.

ORAL INSECT REPELLENTS - INSECT TASTE RECEPTORS AND THEIR ACTION,

Science.gov (United States)

CULICIDAE, * CHEMORECEPTORS ), INSECT REPELLENTS, ELECTROPHYSIOLOGY, STIMULATION(PHYSIOLOGY), ELECTROLYTES(PHYSIOLOGY), BLOOD, INGESTION(PHYSIOLOGY), REPRODUCTION(PHYSIOLOGY), NUTRITION, ENTOMOLOGY, AEDES, MOUTH

Instability in Thoracolumbar Trauma: Is a New Definition Warranted?

Science.gov (United States)

Abbasi Fard, Salman; Skoch, Jesse; Avila, Mauricio J; Patel, Apar S; Sattarov, Kamran V; Walter, Christina M; Baaj, Ali A

2017-10-01

Review of the articles. The objective of this study was to review all articles related to spinal instability to determine a consensus statement for a contemporary, practical definition applicable to thoracolumbar injuries. Traumatic fractures of the thoracolumbar spine are common. These injuries can result in neurological deficits, disability, deformity, pain, and represent a great economic burden to society. The determination of spinal instability is an important task for spine surgeons, as treatment strategies rely heavily on this assessment. However, a clinically applicable definition of spinal stability remains elusive. A review of the Medline database between 1930 and 2014 was performed limited to papers in English. Spinal instability, thoracolumbar, and spinal stability were used as search terms. Case reports were excluded. We reviewed listed references from pertinent search results and located relevant manuscripts from these lists as well. The search produced a total of 694 published articles. Twenty-five articles were eligible after abstract screening and underwent full review. A definition for spinal instability was described in only 4 of them. Definitions were primarily based on biomechanical and classification studies. No definitive parameters were outlined to define stability. Thirty-six years after White and Panjabi's original definition of instability, and many classification schemes later, there remains no practical and meaningful definition for spinal instability in thoracolumbar trauma. Surgeon expertise and experience remains an important factor in stability determination. We propose that, at an initial assessment, a distinction should be made between immediate and delayed instability. This designation should better guide surgeons in decision making and patient counseling.

incidence and distribution of insect pests in rain-fed wheat in eastern

African Journals Online (AJOL)

ACSS

Insect pests are some of the major constraints limiting yield of wheat (Triticum aestivum L.) in East Africa. The objective of this ... control measure applied, type of variety grown and agronomic .... development of an integrated pest management.

Ignition target and laser-plasma instabilities

International Nuclear Information System (INIS)

Laffite, S.; Loiseau, P.

2010-01-01

For the first time indirect drive ignition targets have been designed with the constraint of limiting laser-plasma instabilities. The amplification of these instabilities is directly proportional to the luminous flux density, it means to the sizes of the focal spots too. This study shows that increasing the sizes of the focal spots does not reduce linear amplification gains in a proportional way because the global optimization of the target implies changes in hydrodynamical conditions that in turn have an impact on the value of the amplification gain. The design of the target is a 2-step approach: the first step aims at assuring a uniform irradiation and compression of the target. The first step requires information concerning the laser focusing spots, the dimensions of the hohlraum, the inert gas contained in it, the materials of the wall. The second step is an optimization approach whose aim is to reduce the risk of laser-plasmas instabilities. This optimization is made through simulations of the amplification gains of stimulated Raman and Brillouin backscattering. This method has allowed us to design an optimized target for a rugby-shaped hohlraum. (A.C.)

Genomic instability following irradiation

International Nuclear Information System (INIS)

Hacker-Klom, U.B.; Goehde, W.

2001-01-01

Ionising irradiation may induce genomic instability. The broad spectrum of stress reactions in eukaryontic cells to irradiation complicates the discovery of cellular targets and pathways inducing genomic instability. Irradiation may initiate genomic instability by deletion of genes controlling stability, by induction of genes stimulating instability and/or by activating endogeneous cellular viruses. Alternatively or additionally it is discussed that the initiation of genomic instability may be a consequence of radiation or other agents independently of DNA damage implying non nuclear targets, e.g. signal cascades. As a further mechanism possibly involved our own results may suggest radiation-induced changes in chromatin structure. Once initiated the process of genomic instability probably is perpetuated by endogeneous processes necessary for proliferation. Genomic instability may be a cause or a consequence of the neoplastic phenotype. As a conclusion from the data available up to now a new interpretation of low level radiation effects for radiation protection and in radiotherapy appears useful. The detection of the molecular mechanisms of genomic instability will be important in this context and may contribute to a better understanding of phenomenons occurring at low doses <10 cSv which are not well understood up to now. (orig.)

Mass-rearing for sterile insect release

International Nuclear Information System (INIS)

Parker, A.G.

2005-01-01

As the sterile insect technique (SIT) relies upon released sterile male insects efficiently competing with wild males to mate with wild females, it follows that mass-rearing of insects is one of the principal steps in the process. Mass-rearing for the SIT presents both problems and opportunities due to the increased scale involved compared with rearing insects for most other purposes. This chapter discusses facility design, environmental concerns, strain management, quality control, automation, diet, sex separation, marking, and storage in relation to rearing for the SIT. (author)

Insects diversity in lima bean (Phaseolus lunatus

Directory of Open Access Journals (Sweden)

WIWIN SETIAWATI

2005-10-01

Full Text Available Lima bean (Phaseolus lunatus is a vegetable which usually made as a home yard plant for Indonesian people to fulfill their daily needs. This plant has not been produced in the large number by the farmer. So it is hard to find in the market. Lima bean is light by many kind of insect. Inventory, identification and the study of insect taxon to this plant is being done to collect some information about the insect who life in the plant. The research was done in Balitsa experiment garden in the district of Lembang in Bandung regency on November 2003-February 2004, the experiment start at 4 weeks age, at the height of 1260 m over the sea level. The observation was made systematically by absolute method (D-vac macine and relative method (sweeping net. The research so that there were 26 species of phytofagous insect, 9 species of predator insect, 6 species of parasitoid insect, 4 species of pollinator and 14 species of scavenger insect. According to the research the highest species number was got in the 8th week (3rd sampling, which had 27 variety of species, so the highest diversity was also got in this with 2,113 point. Aphididae and Cicadellidae was the most insect found in roay plant. The research also had high number of species insect so the diversity of insect and evenness become high. A community will have the high stability if it is a long with the high diversity. High evenness in community that has low species dominance and high species number of insect so the high of species richness.

Study of MHD stability beta limit in LHD by hierarchy integrated simulation code

International Nuclear Information System (INIS)

Sato, M.; Watanabe, K.Y.; Nakamura, Y.

2008-10-01

The beta limit by the ideal MHD instabilities (so-called 'MHD stability beta limit') for helical plasmas is studied by a hierarchy integrated simulation code. A numerical model for the effect of the MHD instabilities is introduced such that the pressure profile is flattened around the rational surface due to the MHD instabilities. The width of the flattening of the pressure gradient is determined from the width of the eigenmode structure of the MHD instabilities. It is assumed that there is the upper limit of the mode number of the MHD instabilities which directly affect the pressure gradient. The upper limit of the mode number is determined using a recent high beta experiment in the Large Helical Device (LHD). The flattening of the pressure gradient is calculated by the transport module in a hierarchy integrated code. The achievable volume averaged beta value in the LHD is expected to be beyond 6%. (author)

Assessing Spontaneous Combustion Instability with Nonlinear Time Series Analysis

Science.gov (United States)

Eberhart, C. J.; Casiano, M. J.

2015-01-01

Considerable interest lies in the ability to characterize the onset of spontaneous instabilities within liquid propellant rocket engine (LPRE) combustion devices. Linear techniques, such as fast Fourier transforms, various correlation parameters, and critical damping parameters, have been used at great length for over fifty years. Recently, nonlinear time series methods have been applied to deduce information pertaining to instability incipiency hidden in seemingly stochastic combustion noise. A technique commonly used in biological sciences known as the Multifractal Detrended Fluctuation Analysis has been extended to the combustion dynamics field, and is introduced here as a data analysis approach complementary to linear ones. Advancing, a modified technique is leveraged to extract artifacts of impending combustion instability that present themselves a priori growth to limit cycle amplitudes. Analysis is demonstrated on data from J-2X gas generator testing during which a distinct spontaneous instability was observed. Comparisons are made to previous work wherein the data were characterized using linear approaches. Verification of the technique is performed by examining idealized signals and comparing two separate, independently developed tools.

Combustion instability modeling and analysis

Energy Technology Data Exchange (ETDEWEB)

Santoro, R.J.; Yang, V.; Santavicca, D.A. [Pennsylvania State Univ., University Park, PA (United States); Sheppard, E.J. [Tuskeggee Univ., Tuskegee, AL (United States). Dept. of Aerospace Engineering

1995-12-31

It is well known that the two key elements for achieving low emissions and high performance in a gas turbine combustor are to simultaneously establish (1) a lean combustion zone for maintaining low NO{sub x} emissions and (2) rapid mixing for good ignition and flame stability. However, these requirements, when coupled with the short combustor lengths used to limit the residence time for NO formation typical of advanced gas turbine combustors, can lead to problems regarding unburned hydrocarbons (UHC) and carbon monoxide (CO) emissions, as well as the occurrence of combustion instabilities. The concurrent development of suitable analytical and numerical models that are validated with experimental studies is important for achieving this objective. A major benefit of the present research will be to provide for the first time an experimentally verified model of emissions and performance of gas turbine combustors. The present study represents a coordinated effort between industry, government and academia to investigate gas turbine combustion dynamics. Specific study areas include development of advanced diagnostics, definition of controlling phenomena, advancement of analytical and numerical modeling capabilities, and assessment of the current status of our ability to apply these tools to practical gas turbine combustors. The present work involves four tasks which address, respectively, (1) the development of a fiber-optic probe for fuel-air ratio measurements, (2) the study of combustion instability using laser-based diagnostics in a high pressure, high temperature flow reactor, (3) the development of analytical and numerical modeling capabilities for describing combustion instability which will be validated against experimental data, and (4) the preparation of a literature survey and establishment of a data base on practical experience with combustion instability.

Forest Health Management and Detection of Invasive Forest Insects

Directory of Open Access Journals (Sweden)

Kaelyn Finley

2016-05-01

Full Text Available The objectives of this review paper are to provide an overview of issues related to forest health and forest entomology, explain existing methods for forest insect pest detection, and provide background information on a case study of emerald ash borer. Early detection of potentially invasive insect species is a key aspect of preventing these species from causing damage. Invasion management efforts are typically more feasible and efficient if they are applied as early as possible. Two proposed approaches for detection are highlighted and include dendroentomology and near infrared spectroscopy (NIR. Dendroentomology utilizes tree ring principles to identify the years of outbreak and the dynamics of past insect herbivory on trees. NIR has been successfully used for assessing various forest health concerns (primarily hyperspectral imaging and decay in trees. Emerald ash borer (EAB (Agrilus planipennis, is a non-native beetle responsible for widespread mortality of several North American ash species (Fraxinus sp.. Current non-destructive methods for early detection of EAB in specific trees are limited, which restricts the effectiveness of management efforts. Ongoing research efforts are focused on developing methods for early detection of emerald ash borer.

Diet and trophic groups of an aquatic insect community in a tropical stream

Directory of Open Access Journals (Sweden)

R. L. Motta

Full Text Available The diet and trophic groups of an assemblage of aquatic insects were studied in a tropical stream. Genera of the orders Ephemeroptera, Odonata, Plecoptera, Lepidoptera, and Hemiptera showed feeding specialization. Others, such as Trichoptera, Coleoptera, and Diptera, showed great diet variation with genera of different trophic groups. Seasonal variation of insect diet, evident only for some genera of the orders Trichoptera, Lepidoptera, Coleoptera, and Diptera, was due to the differences observed in community composition and to generalist habits of these genera. However, the seasonal comparison of trophic groups showed no significant statistical differences. The great importance of organic matter, a non-limited resource, in the diet of Ribeirão do Atalho aquatic insects may be the explanation for the trophic stability in this community organization.

Limiting opportunities for cheating stabilizes virulence in insect parasitic nematodes.

Science.gov (United States)

Shapiro-Ilan, David; Raymond, Ben

2016-03-01

Cooperative secretion of virulence factors by pathogens can lead to social conflict when cheating mutants exploit collective secretion, but do not contribute to it. If cheats outcompete cooperators within hosts, this can cause loss of virulence. Insect parasitic nematodes are important biocontrol tools that secrete a range of significant virulence factors. Critically, effective nematodes are hard to maintain without live passage, which can lead to virulence attenuation. Using experimental evolution, we tested whether social cheating might explain unstable virulence in the nematode Heterorhabditis floridensis by manipulating relatedness via multiplicity of infection (MOI), and the scale of competition. Passage at high MOI, which should reduce relatedness, led to loss of fitness: virulence and reproductive rate declined together and all eight independent lines suffered premature extinction. As theory predicts, relatedness treatments had more impact under stronger global competition. In contrast, low MOI passage led to more stable virulence and increased reproduction. Moreover, low MOI lineages showed a trade-off between virulence and reproduction, particularly for lines under stronger between-host competition. Overall, this study indicates that evolution of virulence theory is valuable for the culture of biocontrol agents: effective nematodes can be improved and maintained if passage methods mitigate possible social conflicts.

Widespread range expansions shape latitudinal variation in insect thermal limits

Science.gov (United States)

Lancaster, Lesley T.

2016-06-01

Current anthropogenic impacts, including habitat modification and climate change, may contribute to a sixth mass extinction. To mitigate these impacts and slow further losses of biodiversity, we need to understand which species are most at risk and identify the factors contributing to current and future declines. Such information is often obtained through large-scale, comparative and biogeographic analysis of lineages or traits that are potentially sensitive to ongoing anthropogenic change--for instance to predict which regions are most susceptible to climate change-induced biodiversity loss. However, for this approach to be generally successful, the underlying causes of identified geographical trends need to be carefully considered. Here, I augment and reanalyse a global data set of insect thermal tolerances, evaluating the contribution of recent and contemporary range expansions to latitudinal variation in thermal niche breadth. Previous indications that high-latitude ectotherms exhibit broad thermal niches and high warming tolerances held only for species undergoing range expansions or invasions. In contrast, species with stable or declining geographic ranges exhibit latitudinally decreasing absolute thermal tolerances and no latitudinal variation in tolerance breadths. Thus, non-range-expanding species, particularly insular or endemic species, which are often of highest conservation priority, are unlikely to tolerate future climatic warming at high latitudes.

Radioisotopes and food preservation against insects

International Nuclear Information System (INIS)

Hachem Ahmad, M.S.

1998-01-01

The book describes how to preserve food from harmful insects by using radioisotopes. It focusses on the impact of ionized radiation on the different stages of insect growth and on its metabolism and immunity. It also discusses the relationship between radiation doses and insect reproduction. It explains the various methods to detect the irradiated foods

Regions identity between the genome of vertebrates and non-retroviral families of insect viruses.

Science.gov (United States)

Fan, Gaowei; Li, Jinming

2011-11-10

The scope of our understanding of the evolutionary history between viruses and animals is limited. The fact that the recent availability of many complete insect virus genomes and vertebrate genomes as well as the ability to screen these sequences makes it possible to gain a new perspective insight into the evolutionary interaction between insect viruses and vertebrates. This study is to determine the possibility of existence of sequence identity between the genomes of insect viruses and vertebrates, attempt to explain this phenomenon in term of genetic mobile element, and try to investigate the evolutionary relationship between these short regions of identity among these species. Some of studied insect viruses contain variable numbers of short regions of sequence identity to the genomes of vertebrate with nucleotide sequence length from 28 bp to 124 bp. They are found to locate in multiple sites of the vertebrate genomes. The ontology of animal genes with identical regions involves in several processes including chromatin remodeling, regulation of apoptosis, signaling pathway, nerve system development and some enzyme-like catalysis. Phylogenetic analysis reveals that at least some short regions of sequence identity in the genomes of vertebrate are derived the ancestral of insect viruses. Short regions of sequence identity were found in the vertebrates and insect viruses. These sequences played an important role not only in the long-term evolution of vertebrates, but also in promotion of insect virus. This typical win-win strategy may come from natural selection.

On Nonlinear Combustion Instability in Liquid Propellant Rocket Motors

Science.gov (United States)

Sims, J. D. (Technical Monitor); Flandro, Gary A.; Majdalani, Joseph; Sims, Joseph D.

2004-01-01

All liquid propellant rocket instability calculations in current use have limited value in the predictive sense and serve mainly as a correlating framework for the available data sets. The well-known n-t model first introduced by Crocco and Cheng in 1956 is still used as the primary analytical tool of this type. A multitude of attempts to establish practical analytical methods have achieved only limited success. These methods usually produce only stability boundary maps that are of little use in making critical design decisions in new motor development programs. Recent progress in understanding the mechanisms of combustion instability in solid propellant rockets"' provides a firm foundation for a new approach to prediction, diagnosis, and correction of the closely related problems in liquid motor instability. For predictive tools to be useful in the motor design process, they must have the capability to accurately determine: 1) time evolution of the pressure oscillations and limit amplitude, 2) critical triggering pulse amplitude, and 3) unsteady heat transfer rates at injector surfaces and chamber walls. The method described in this paper relates these critical motor characteristics directly to system design parameters. Inclusion of mechanisms such as wave steepening, vorticity production and transport, and unsteady detonation wave phenomena greatly enhance the representation of key features of motor chamber oscillatory behavior. The basic theoretical model is described and preliminary computations are compared to experimental data. A plan to develop the new predictive method into a comprehensive analysis tool is also described.

Triclade: influence of a sinuous secondary instability on the Richtmyer-Meshkov instabilities; Triclade: influence d'une instabilite sinueuse sur les instabilites de Richtmyer-Meshkov en 2D et 3D

Energy Technology Data Exchange (ETDEWEB)

Boulet, M.; Griffond, J. [CEA Bruyeres-le-Chatel, Dept. Sciences de la Simulation et de l' Information, 91 (France)

2004-07-01

Occurrence of a secondary instability developing after the Richtmyer-Meshkov (primary) instability is emphasized thanks to numerical simulations with the TRICLADE code. We are mainly considering 2D perturbations describes by trigonometric function cosine or [cosine]. However, the 3D case is also tackled. The sinuous secondary instability is characterized by the loss of the symmetries in the direction normal to the interface at its crests. It reduces the late time growing rate of the 'mushrooms' formed by the Richtmyer-Meshkov instability. Related simplified problems, like symmetrical Riemann problems or the Mallier-Maslowe array of counter-rotating vortices, allow us to perform 2D linear stability analysis. Thus, we show that the sinuous secondary instability is not a numerical artifact and that is comes from the continuous incompressible velocity field in the interface region. This instability implies temporal limitations for the validity of single mode simulations; therefore multimode simulations are necessary to study the ]ate-time behaviour of interfaces bitted by shocks. (authors)

Social immunity and the evolution of group living in insects.

Science.gov (United States)

Meunier, Joël

2015-05-26

The evolution of group living requires that individuals limit the inherent risks of parasite infection. To this end, group living insects have developed a unique capability of mounting collective anti-parasite defences, such as allogrooming and corpse removal from the nest. Over the last 20 years, this phenomenon (called social immunity) was mostly studied in eusocial insects, with results emphasizing its importance in derived social systems. However, the role of social immunity in the early evolution of group living remains unclear. Here, I investigate this topic by first presenting the definitions of social immunity and discussing their applications across social systems. I then provide an up-to-date appraisal of the collective and individual mechanisms of social immunity described in eusocial insects and show that they have counterparts in non-eusocial species and even solitary species. Finally, I review evidence demonstrating that the increased risks of parasite infection in group living species may both decrease and increase the level of personal immunity, and discuss how the expression of social immunity could drive these opposite effects. By highlighting similarities and differences of social immunity across social systems, this review emphasizes the potential importance of this phenomenon in the early evolution of the multiple forms of group living in insects. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Diseases in insects produced for food and feed

DEFF Research Database (Denmark)

Eilenberg, Jørgen; Vlak, J.M.; Nielsen-Leroux, C.

2015-01-01

Increased production of insects on a large scale for food and feed will likely lead to many novel challenges, including problems with diseases. We provide an overview of important groups of insect pathogens, which can cause disease in insects produced for food and feed. Main characteristics of each...... pathogen group (viruses, bacteria, fungi, protists and nematodes) are described and illustrated, with a selection of examples from the most commonly produced insect species for food and feed. Honeybee and silkworm are mostly produced for other reasons than as human food, yet we can still use them...... as examples to learn about emergence of new diseases in production insects. Results from a 2014 survey about insect diseases in current insect production systems are presented for the first time. Finally, we give some recommendations for the prevention and control of insect diseases. Key words: disease...

Dissipative-drift wave instability in the presence of impurity radiation

International Nuclear Information System (INIS)

Bharuthram, R.; Shukla, P.K.

1992-01-01

It is believed that electrostatic fluctuations in edge plasmas are usually triggered by micro and macroscopic plasma instabilities. The latter involve dissipative-drift waves as well as tearing and rippling modes in nonuniform plasmas. However, if the plasma edge contains impurity radiation, then the radiative condensation instability could be the cause of nonthermal fluctuations. The radiative condensation instabilities have been extensively investigated in a homogeneous plasma by many authors. The effect of equilibrium density and electron temperature inhomogeneities in the study of radiative condensation instabilities has been examined by Shukla and Yu. They found new drift-like modes driven by the combined effect of impurity radiation loss and the equilibrium density and temperature gradients. The analyses of Shukla and Yu is, however, limited to low-frequency, long wavelength collisionless drift waves. Since the edge plasma of toroidal devices is highly collisional, the results of collisionless theories cannot be directly applied to explain the origin of nonthermal fluctuations. In this paper, we study the influence of impurity radiation on the dissipative-drift wave instability in a collision-dominated nonuniform plasma embedded in a homogeneous magnetic field. (author) 6 refs

Protein quality of insects as potential ingredients for dog and cat foods.

Science.gov (United States)

Bosch, Guido; Zhang, Sheng; Oonincx, Dennis G A B; Hendriks, Wouter H

2014-01-01

Insects have been proposed as a high-quality, efficient and sustainable dietary protein source. The present study evaluated the protein quality of a selection of insect species. Insect substrates were housefly pupae, adult house cricket, yellow mealworm larvae, lesser mealworm larvae, Morio worm larvae, black soldier fly larvae and pupae, six spot roach, death's head cockroach and Argentinean cockroach. Reference substrates were poultry meat meal, fish meal and soyabean meal. Substrates were analysed for DM, N, crude fat, ash and amino acid (AA) contents and for in vitro digestibility of organic matter (OM) and N. The nutrient composition, AA scores as well as in vitro OM and N digestibility varied considerably between insect substrates. For the AA score, the first limiting AA for most substrates was the combined requirement for Met and Cys. The pupae of the housefly and black soldier fly were high in protein and had high AA scores but were less digestible than other insect substrates. The protein content and AA score of house crickets were high and similar to that of fish meal; however, in vitro N digestibility was higher. The cockroaches were relatively high in protein but the indispensable AA contents, AA scores and the in vitro digestibility values were relatively low. In addition to the indices of protein quality, other aspects such as efficiency of conversion of organic side streams, feasibility of mass-production, product safety and pet owner perception are important for future dog and cat food application of insects as alternative protein source.

Evaluating Insects as Bioindicators of Heavy Metal Contamination and Accumulation near Industrial Area of Gujrat, Pakistan

Directory of Open Access Journals (Sweden)

Iqra Azam

2015-01-01

Full Text Available To study the accumulation and contamination of heavy metals (i.e., Cd, Cr, Cu, Ni, and Zn in soil, air, and water, few insect species were assayed as ecological indicators. Study area comes under industrial zone of district Gujrat of Punjab, Pakistan. Insects used as bioindicators included a libellulid dragonfly (Crocothemis servilia, an acridid grasshopper (Oxya hyla hyla, and a nymphalid butterfly (Danaus chrysippus near industrial zone of Gujrat. Accumulation of Cd was highest in insect species followed by Cu, Cr, Zn, and Ni at p<0.05. Hierarchical cluster analysis (HACA was carried out to study metal accumulation level in all insects. Correlation and regression analysis confirmed HACA observations and declared concentration of heavy metals above permissible limits. Metal concentrations in insects were significantly higher near industries and nallahs in Gujrat and relatively higher concentrations of metals were found in Orthoptera than Odonata and Lepidoptera. The total metal concentrations in insects were pointed significantly higher at sites S3 (Mid of HalsiNala, S9 (End of HalsiNala, and S1 (Start of HalsiNala, whereas lowest value was detected at site S6 (Kalra Khasa located far from industrial area. HACA indicates that these insect groups are potential indicators of metal contamination and can be used in biomonitoring.

A new approach to quantify semiochemical effects on insects based on energy landscapes.

Directory of Open Access Journals (Sweden)

Rory P Wilson

Full Text Available Our ability to document insect preference for semiochemicals is pivotal in pest control as these agents can improve monitoring and be deployed within integrated pest management programmes for more efficacious control of pest species. However, methods used to date have drawbacks that limit their utility. We present and test a new concept for determining insect motivation to move towards, or away from, semiochemicals by noting direction and speed of movement as animals work against a defined energy landscape (environmentally dependent variation in the cost of transport requiring different powers to negotiate. We conducted trials with the pine weevils Hylobius abietis and peach-potato aphids Myzus persicae exposed to various attractants and repellents and placed so that they either moved up defined slopes against gravity or had to travel over variously rough surfaces.Linear Mixed Models demonstrated clear reductions in travel speed by insects moving along increasingly energetically taxing energy landscapes but also that responses varied according to different semiochemicals, thus highlighting the value of energy landscapes as a new concept to help measure insect motivation to access or avoid different attractants or repellents across individuals.New sensitive, detailed indicators of insect motivation derived from this approach should prove important in pest control across the world.

Plasma instabilities multifrequency study in equatorial electrojet

International Nuclear Information System (INIS)

Hanuise, C.

1983-01-01

In this thesis, multifrequential HF coherent radar results are presented, in the field plasma instabilities in equatorial electrojet. In a first part, characteristics of the irregularities observed either at the 3 meter wavelength by VHF radars, either at other wavelengths during pinpoint experiments, or in-situ by probe rockets are recalled. Theoretical studies progressed and are presented, at the same time with these experimental observations: instability linear theory, non linear theories, HF radar specificity, and problems associated to HF waves propagation and refraction in ionosphere. Original experimental results from Ethiopia are gathered in the second part. Plasma instability has been studied in different geophysical conditions and Doppler spectra characteristics are presented for each one of them. These characteristics are completely different according to the various cases; they are also different according to wether observations are made during the day in normal conditions (electric field pointed to the east at the equator) or in counter-electrojet conditions (electric field pointed to the west). The last part is concerned with theoretical interpretation of the previous results. A comprehensive view of the instability physical mechanisms, according to the geophysical conditions encountered, has been allowed by our results, VHF radar measurements at Jicamarca, or in situ probe measurements on the whole. Irregularities study has been limited to the E region [fr

Cavitation instability as a trigger of aneurysm rupture.

Science.gov (United States)

Volokh, K Y

2015-10-01

Aneurysm formation and growth is accompanied by microstructural alterations in the arterial wall. Particularly, the loss of elastin may lead to tissue disintegration and appearance of voids or cavities at the micron scale. Unstable growth and coalescence of voids may be a predecessor and trigger for the onset of macroscopic cracks. In the present work, we analyze the instability of membrane (2D) and bulk (3D) voids under hydrostatic tension by using two experimentally calibrated constitutive models of abdominal aortic aneurysm enhanced with energy limiters. The limiters provide the saturation value for the strain energy, which indicates the maximum energy that can be stored and dissipated by an infinitesimal material volume. We find that the unstable growth of voids can start when the critical stress is considerably less than the aneurysm strength. Moreover, this critical stress may even approach the arterial wall stress in the physiological range. This finding suggests that cavitation instability can be a rational indicator of the aneurysm rupture.

Transcription factor E93 specifies adult metamorphosis in hemimetabolous and holometabolous insects.

Science.gov (United States)

Ureña, Enric; Manjón, Cristina; Franch-Marro, Xavier; Martín, David

2014-05-13

All immature animals undergo remarkable morphological and physiological changes to become mature adults. In winged insects, metamorphic changes either are limited to a few tissues (hemimetaboly) or involve a complete reorganization of most tissues and organs (holometaboly). Despite the differences, the genetic switch between immature and adult forms in both types of insects relies on the disappearance of the antimetamorphic juvenile hormone (JH) and the transcription factors Krüppel-homolog 1 (Kr-h1) and Broad-Complex (BR-C) during the last juvenile instar. Here, we show that the transcription factor E93 is the key determinant that promotes adult metamorphosis in both hemimetabolous and holometabolous insects, thus acting as the universal adult specifier. In the hemimetabolous insect Blattella germanica, BgE93 is highly expressed in metamorphic tissues, and RNA interference (RNAi)-mediated knockdown of BgE93 in the nymphal stage prevented the nymphal-adult transition, inducing endless reiteration of nymphal development, even in the absence of JH. We also find that BgE93 down-regulated BgKr-h1 and BgBR-C expression during the last nymphal instar of B. germanica, a key step necessary for proper adult differentiation. This essential role of E93 is conserved in holometabolous insects as TcE93 RNAi in Tribolium castaneum prevented pupal-adult transition and produced a supernumerary second pupa. In this beetle, TcE93 also represses expression of TcKr-h1 and TcBR-C during the pupal stage. Similar results were obtained in the more derived holometabolous insect Drosophila melanogaster, suggesting that winged insects use the same regulatory mechanism to promote adult metamorphosis. This study provides an important insight into the understanding of the molecular basis of adult metamorphosis.

Simulation of Instability at Transition Energy with a New Impedance Model for CERN PS

CERN Document Server

Wang, Na; Biancacci, Nicolo; Migliorati, Mauro; Persichelli, Serena; Sterbini, Guido

2016-01-01

Instabilities driven by the transverse impedance are proven to be one of the limitations for the high intensity reach of the CERN PS. Since several years, fast single bunch vertical instability at transition energy has been observed with the high intensity bunch serving the neu-tron Time-of-Flight facility (n-ToF). In order to better understand the instability mechanism, a dedicated meas-urement campaign took place. The results were compared with macro-particle simulations with PyHEADTAIL based on the new impedance model developed for the PS. Instability threshold and growth rate for different longitu-dinal emittances and beam intensities were studied.

The temporal interplay of self-esteem instability and affective instability in borderline personality disorder patients' everyday lives.

Science.gov (United States)

Santangelo, Philip S; Reinhard, Iris; Koudela-Hamila, Susanne; Bohus, Martin; Holtmann, Jana; Eid, Michael; Ebner-Priemer, Ulrich W

2017-11-01

Borderline personality disorder (BPD) is defined by a pervasive pattern of instability. Although there is ample empirical evidence that unstable self-esteem is associated with a myriad of BPD-like symptoms, self-esteem instability and its temporal dynamics have received little empirical attention in patients with BPD. Even worse, the temporal interplay of affective instability and self-esteem instability has been neglected completely, although it has been hypothesized recently that the lack of specificity of affective instability in association with BPD might be explained by the highly intertwined temporal relationship between affective and self-esteem instability. To investigate self-esteem instability, its temporal interplay with affective instability, and its association with psychopathology, 60 patients with BPD and 60 healthy controls (HCs) completed electronic diaries for 4 consecutive days during their everyday lives. Participants reported their current self-esteem, valence, and tense arousal levels 12 times a day in approximately one-hr intervals. We used multiple state-of-the-art statistical techniques and graphical approaches to reveal patterns of instability, clarify group differences, and examine the temporal interplay of self-esteem instability and affective instability. As hypothesized, instability in both self-esteem and affect was clearly elevated in the patients with BPD. In addition, self-esteem instability and affective instability were highly correlated. Both types of instability were related to general psychopathology. Because self-esteem instability could not fully explain affective instability and vice versa and neither affective instability nor self-esteem instability was able to explain psychopathology completely, our findings suggest that these types of instability represent unique facets of BPD. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Increasing cell-device adherence using cultured insect cells for receptor-based biosensors

Science.gov (United States)

Terutsuki, Daigo; Mitsuno, Hidefumi; Sakurai, Takeshi; Okamoto, Yuki; Tixier-Mita, Agnès; Toshiyoshi, Hiroshi; Mita, Yoshio; Kanzaki, Ryohei

2018-03-01

Field-effect transistor (FET)-based biosensors have a wide range of applications, and a bio-FET odorant sensor, based on insect (Sf21) cells expressing insect odorant receptors (ORs) with sensitivity and selectivity, has emerged. To fully realize the practical application of bio-FET odorant sensors, knowledge of the cell-device interface for efficient signal transfer, and a reliable and low-cost measurement system using the commercial complementary metal-oxide semiconductor (CMOS) foundry process, will be indispensable. However, the interfaces between Sf21 cells and sensor devices are largely unknown, and electrode materials used in the commercial CMOS foundry process are generally limited to aluminium, which is reportedly toxic to cells. In this study, we investigated Sf21 cell-device interfaces by developing cross-sectional specimens. Calcium imaging of Sf21 cells expressing insect ORs was used to verify the functions of Sf21 cells as odorant sensor elements on the electrode materials. We found that the cell-device interface was approximately 10 nm wide on average, suggesting that the adhesion mechanism of Sf21 cells may differ from that of other cells. These results will help to construct accurate signal detection from expressed insect ORs using FETs.

Bugs, butterflies, and spiders: children's understandings about insects

Science.gov (United States)

Shepardson, Daniel P.

2002-06-01

This article explores elementary children's ideas about insects. The study involved 20 children from each grade level, kindergarten through fifth-grade, for a total of 120 children. The data collection procedure was designed to investigate what an insect means to children, through the use of three different tasks: draw and explain, interview about instances, and the formulation of a general rule. Considering children's responses to the three tasks, I found that their ideas about insects reflect understandings based on physical characteristics of size and shape, arthropod characteristics, insect characteristics, human-insect interactions, life habits of insects, feeding habits of insects, and means of locomotion. Children's understandings are juxtaposed to that of a scientific perspective, elucidating implications for curriculum development and instructional practice.

Tearing instabilities in turbulence

International Nuclear Information System (INIS)

Ishizawa, A.; Nakajima, N.

2009-01-01

Full text: Effects of micro-turbulence on tearing instabilities are investigated by numerically solving a reduced set of two-fluid equations. Micro-turbulence excites both large-scale and small-scale Fourier modes through energy transfer due to nonlinear mode coupling. The energy transfer to large scale mode does not directly excite tearing instability but it gives an initiation of tearing instability. When tearing instability starts to grow, the excited small scale mode plays an important role. The mixing of magnetic flux by micro-turbulence is the dominant factor of non-ideal MHD effect at the resonant surface and it gives rise to magnetic reconnection which causes tearing instability. Tearing instabilities were investigated against static equilibrium or flowing equilibrium so far. On the other hand, the recent progress of computer power allows us to investigate interactions between turbulence and coherent modes such as tearing instabilities in magnetically confined plasmas by means of direct numerical simulations. In order to investigate effects of turbulence on tearing instabilities we consider a situation that tearing mode is destabilized in a quasi-equilibrium including micro-turbulence. We choose an initial equilibrium that is unstable against kinetic ballooning modes and tearing instabilities. Tearing instabilities are current driven modes and thus they are unstable for large scale Fourier modes. On the other hand kinetic ballooning modes are unstable for poloidal Fourier modes that are characterized by ion Larmor radius. The energy of kinetic ballooning modes spreads over wave number space through nonlinear Fourier mode coupling. We present that micro-turbulence affects tearing instabilities in two different ways by three-dimensional numerical simulation of a reduced set of two-fluid equations. One is caused by energy transfer to large scale modes, the other is caused by energy transfer to small scale modes. The former is the excitation of initial

Testing mechanistic models of growth in insects.

Science.gov (United States)

Maino, James L; Kearney, Michael R

2015-11-22

Insects are typified by their small size, large numbers, impressive reproductive output and rapid growth. However, insect growth is not simply rapid; rather, insects follow a qualitatively distinct trajectory to many other animals. Here we present a mechanistic growth model for insects and show that increasing specific assimilation during the growth phase can explain the near-exponential growth trajectory of insects. The presented model is tested against growth data on 50 insects, and compared against other mechanistic growth models. Unlike the other mechanistic models, our growth model predicts energy reserves per biomass to increase with age, which implies a higher production efficiency and energy density of biomass in later instars. These predictions are tested against data compiled from the literature whereby it is confirmed that insects increase their production efficiency (by 24 percentage points) and energy density (by 4 J mg(-1)) between hatching and the attainment of full size. The model suggests that insects achieve greater production efficiencies and enhanced growth rates by increasing specific assimilation and increasing energy reserves per biomass, which are less costly to maintain than structural biomass. Our findings illustrate how the explanatory and predictive power of mechanistic growth models comes from their grounding in underlying biological processes. © 2015 The Author(s).

Potential of Insect-Derived Ingredients for Food Applications

NARCIS (Netherlands)

Tzompa Sosa, D.A.; Fogliano, V.

2017-01-01

Insects are a sustainable and efficient protein and lipid source, compared with conventional livestock. Moreover, insect proteins and lipids are highly nutritional. Therefore, insect proteins and lipids can find its place as food ingredients. The use of insect proteins and lipids as food ingredients

Prospective evidence for independent nitrogen and phosphorus limitation of grasshopper (Chorthippus curtipennis) growth in a tallgrass prairie.

Science.gov (United States)

Rode, Madison; Lemoine, Nathan P; Smith, Melinda D

2017-01-01

Insect herbivores play a pivotal role in regulating plant production and community composition, and their role in terrestrial ecosystems is partly determined by their feeding behavior and performance among plants of differing nutritional quality. Historically, nitrogen (N) has been considered the primary limiting nutrient of herbivorous insects, but N is only one of many potential nutrients important to insect performance. Of these nutrients, phosphorus (P) is perhaps the most important because somatic growth depends upon P-rich ribosomal RNA. Yet relatively few studies have assessed the strength of P-limitation for terrestrial insects and even fewer have simultaneously manipulated both N and P to assess the relative strengths of N- and P-limitation. Here, we tested for potential N and P limitation, as well as N:P co-limitation, on Chorthippis curtipennis (Orthoptera, Acrididae), an abundant member of arthropod communities of central US prairies. Our results demonstrate weak evidence for both N and P limitation of C. curtipennis growth rates in laboratory feeding assays. Importantly, P-limitation was just as strong as N-limitation, but we found no evidence for NP co-limitation in our study. Furthermore, nutrient limitation was not apparent in field studies, suggesting that insect growth rates may be predominately controlled by other factors, including temperature and predation. Our results suggest that P should be jointly considered, along with N, as a primary determinant of herbivore feeding behavior under both current and future climate conditions.

Insect pests of sweetpotato in Uganda: farmers' perceptions of their importance and control practices.

Science.gov (United States)

Okonya, Joshua Sikhu; Mwanga, Robert Om; Syndikus, Katja; Kroschel, Jürgen

2014-01-01

Insect pests are among the most important constraints limiting sweetpotato (Ipomoea batatas) production in Africa. However, there is inadequate information about farmers' knowledge, perceptions and practices in the management of key insect pests. This has hindered development of effective pest management approaches for smallholder farmers. A standard questionnaire was used to interview individual sweetpotato farmers (n = 192) about their perception and management practices regarding insect pests in six major sweetpotato producing districts of Uganda. The majority (93%) of farmers perceived insect pests to be a very serious problem. With the exception of Masindi and Wakiso districts where the sweetpotato butterfly (Acraea acerata) was the number one constraint, sweetpotato weevils (Cylas puncticollis and C. brunneus) were ranked as the most important insect pests. Insecticide use in sweetpotato fields was very low being highest (28-38% of households) in districts where A. acerata infestation is the biggest problem. On average, 65% and 87% of the farmers took no action to control A. acerata and Cylas spp., respectively. Farmers were more conversant with the presence of and damage by A. acerata than of Cylas spp. as they thought that Cylas spp. root damage was brought about by a prolonged dry season. Different levels of field resistance (ability of a variety to tolerate damage) of sweetpotato landraces to A. acerata (eight landraces) and Cylas spp. (six landraces) were reported by farmers in all the six districts. This perceived level of resistance to insect damage by landraces needs to be investigated. To improve farmers' capabilities for sweetpotato insect pest management, it is crucial to train them in the basic knowledge of insect pest biology and control.

Review of two-phase instabilities

Energy Technology Data Exchange (ETDEWEB)

Kang, Han Ok; Seo, Han Ok; Kang, Hyung Suk; Cho, Bong Hyun; Lee, Doo Jeong

1997-06-01

KAERI is carrying out a development of the design for a new type of integral reactors. The once-through helical steam generator is important design features. The study on designs and operating conditions which prevent flow instability should precede the introduction of one-through steam generator. Experiments are currently scheduled to understand two-phase instability, evaluate the effect of each design parameter on the critical point, and determine proper inlet throttling for the prevention of instability. This report covers general two-phase instability with review of existing studies on this topics. The general classification of two phase flow instability and the characteristics of each type of instability are first described. Special attention is paid to BWR core flow instability and once-through steam generator instability. The reactivity feedback and the effect of system parameters are treated mainly for BWR. With relation to once-through steam generators, the characteristics of convective heating and dryout point oscillation are first investigated and then the existing experimental studies are summarized. Finally chapter summarized the proposed correlations for instability boundary conditions. (author). 231 refs., 5 tabs., 47 figs

Non-destructive sampling of ancient insect DNA

DEFF Research Database (Denmark)

Thomsen, Philip Francis; Elias, Scott; Gilbert, Tom

2009-01-01

BACKGROUND: A major challenge for ancient DNA (aDNA) studies on insect remains is that sampling procedures involve at least partial destruction of the specimens. A recent extraction protocol reveals the possibility of obtaining DNA from past insect remains without causing visual morphological...... of 77-204 base pairs (-bp) in size using species-specific and general insect primers. CONCLUSION/SIGNIFICANCE: The applied non-destructive DNA extraction method shows promising potential on insect museum specimens of historical age as far back as AD 1820, but less so on the ancient permafrost......-preserved insect fossil remains tested, where DNA was obtained from samples up to ca. 26,000 years old. The non-frozen sediment DNA approach appears to have great potential for recording the former presence of insect taxa not normally preserved as macrofossils and opens new frontiers in research on ancient...

Joint instability and osteoarthritis.

Science.gov (United States)

Blalock, Darryl; Miller, Andrew; Tilley, Michael; Wang, Jinxi

2015-01-01

Joint instability creates a clinical and economic burden in the health care system. Injuries and disorders that directly damage the joint structure or lead to joint instability are highly associated with osteoarthritis (OA). Thus, understanding the physiology of joint stability and the mechanisms of joint instability-induced OA is of clinical significance. The first section of this review discusses the structure and function of major joint tissues, including periarticular muscles, which play a significant role in joint stability. Because the knee, ankle, and shoulder joints demonstrate a high incidence of ligament injury and joint instability, the second section summarizes the mechanisms of ligament injury-associated joint instability of these joints. The final section highlights the recent advances in the understanding of the mechanical and biological mechanisms of joint instability-induced OA. These advances may lead to new opportunities for clinical intervention in the prevention and early treatment of OA.

Use of habitat odour by host-seeking insects.

Science.gov (United States)

Webster, Ben; Cardé, Ring T

2017-05-01

Locating suitable feeding or oviposition sites is essential for insect survival. Understanding how insects achieve this is crucial, not only for understanding the ecology and evolution of insect-host interactions, but also for the development of sustainable pest-control strategies that exploit insects' host-seeking behaviours. Volatile chemical cues are used by foraging insects to locate and recognise potential hosts but in nature these resources usually are patchily distributed, making chance encounters with host odour plumes rare over distances greater than tens of metres. The majority of studies on insect host-seeking have focussed on short-range orientation to easily detectable cues and it is only recently that we have begun to understand how insects overcome this challenge. Recent advances show that insects from a wide range of feeding guilds make use of 'habitat cues', volatile chemical cues released over a relatively large area that indicate a locale where more specific host cues are most likely to be found. Habitat cues differ from host cues in that they tend to be released in larger quantities, are more easily detectable over longer distances, and may lack specificity, yet provide an effective way for insects to maximise their chances of subsequently encountering specific host cues. This review brings together recent advances in this area, discussing key examples and similarities in strategies used by haematophagous insects, soil-dwelling insects and insects that forage around plants. We also propose and provide evidence for a new theory that general and non-host plant volatiles can be used by foraging herbivores to locate patches of vegetation at a distance in the absence of more specific host cues, explaining some of the many discrepancies between laboratory and field trials that attempt to make use of plant-derived repellents for controlling insect pests. © 2016 Cambridge Philosophical Society.

MHD instabilities in astrophysical plasmas: very different from MHD instabilities in tokamaks!

Science.gov (United States)

Goedbloed, J. P.

2018-01-01

The extensive studies of MHD instabilities in thermonuclear magnetic confinement experiments, in particular of the tokamak as the most promising candidate for a future energy producing machine, have led to an ‘intuitive’ description based on the energy principle that is very misleading for most astrophysical plasmas. The ‘intuitive’ picture almost directly singles out the dominant stabilizing field line bending energy of the Alfvén waves and, consequently, concentrates on expansion schemes that minimize that contribution. This happens when the wave vector {{k}}0 of the perturbations, on average, is perpendicular to the magnetic field {B}. Hence, all macroscopic instabilities of tokamaks (kinks, interchanges, ballooning modes, ELMs, neoclassical tearing modes, etc) are characterized by satisfying the condition {{k}}0 \\perp {B}, or nearly so. In contrast, some of the major macroscopic instabilities of astrophysical plasmas (the Parker instability and the magneto-rotational instability) occur when precisely the opposite condition is satisfied: {{k}}0 \\parallel {B}. How do those instabilities escape from the dominance of the stabilizing Alfvén wave? The answer to that question involves, foremost, the recognition that MHD spectral theory of waves and instabilities of laboratory plasmas could be developed to such great depth since those plasmas are assumed to be in static equilibrium. This assumption is invalid for astrophysical plasmas where rotational and gravitational accelerations produce equilibria that are at best stationary, and the associated spectral theory is widely, and incorrectly, believed to be non-self adjoint. These complications are addressed, and cured, in the theory of the Spectral Web, recently developed by the author. Using this method, an extensive survey of instabilities of astrophysical plasmas demonstrates how the Alfvén wave is pushed into insignificance under these conditions to give rise to a host of instabilities that do not

The evolution of plant-insect mutualisms.

Science.gov (United States)

Bronstein, Judith L; Alarcón, Ruben; Geber, Monica

2006-01-01

Mutualisms (cooperative interactions between species) have had a central role in the generation and maintenance of life on earth. Insects and plants are involved in diverse forms of mutualism. Here we review evolutionary features of three prominent insect-plant mutualisms: pollination, protection and seed dispersal. We focus on addressing five central phenomena: evolutionary origins and maintenance of mutualism; the evolution of mutualistic traits; the evolution of specialization and generalization; coevolutionary processes; and the existence of cheating. Several features uniting very diverse insect-plant mutualisms are identified and their evolutionary implications are discussed: the involvement of one mobile and one sedentary partner; natural selection on plant rewards; the existence of a continuum from specialization to generalization; and the ubiquity of cheating, particularly on the part of insects. Plant-insect mutualisms have apparently both arisen and been lost repeatedly. Many adaptive hypotheses have been proposed to explain these transitions, and it is unlikely that any one of them dominates across interactions differing so widely in natural history. Evolutionary theory has a potentially important, but as yet largely unfilled, role to play in explaining the origins, maintenance, breakdown and evolution of insect-plant mutualisms.

The Sterile Insect Technique

International Nuclear Information System (INIS)

Kiragu, J.

2006-01-01

Insect pests have caused an increasing problem in agriculture and human health through crop losses and disease transmission to man and livestock. Intervention to ensure food security and human health has relied on Integrated Pest Management (IPM) strategies to keep the pests population below economic injury levels. IPM integrate a variety of methods, but there has been over-reliance on chemical control following the discovery of insecticidal properties of DDT. It is now realized that, maintaining pest populations at controlled levels is unsustainable and eradication options is now being considered. Although the Sterile Insect Technique(SIT) could be used for insect suppression, it is gaining favour in the elimination (eradication) of the target pest population through Areawide-based IPM (Author)

The internal waves and Rayleigh-Taylor instability in compressible quantum plasmas

International Nuclear Information System (INIS)

Lu, H. L.; Qiu, X. M.

2011-01-01

In this paper, we investigate the quantum effect on internal waves and Rayleigh-Taylor (RT) instability in compressible quantum plasmas. First of all, let us consider the case of the limit of short wavelength perturbations. In the case, the dispersion relation including quantum and compressibility effects and the RT instability growth rate can be derived using Wentzel-Kramers-Brillouin method. The results show that the internal waves can propagate along the transverse direction due to the quantum effect, which was first pointed out by Bychkov et al.[Phys. Lett. A 372, 3042 (2008)], and the coupling between it and compressibility effect, which is found out in this paper. Then, without making the approximation assumption of short wavelength limit, we examine the linearized perturbation equation following Qiu et al.'s solving process [Phys. Plasmas 10, 2956 (2003)]. It is found that the quantum effect always stabilizes the RT instability in either incompressible or compressible quantum plasmas. Moreover, in the latter case, the coupling between it and compressibility effect makes this stabilization further enhance.

Stiffness distribution in insect cuticle: a continuous or a discontinuous profile?

Science.gov (United States)

Rajabi, H; Jafarpour, M; Darvizeh, A; Dirks, J-H; Gorb, S N

2017-07-01

Insect cuticle is a biological composite with a high degree of complexity in terms of both architecture and material composition. Given the complex morphology of many insect body parts, finite-element (FE) models play an important role in the analysis and interpretation of biomechanical measurements, taken by either macroscopic or nanoscopic techniques. Many previous studies show that the interpretation of nanoindentation measurements of this layered composite material is very challenging. To develop accurate FE models, it is of particular interest to understand more about the variations in the stiffness through the thickness of the cuticle. Considering the difficulties of making direct measurements, in this study, we use the FE method to analyse previously published data and address this issue numerically. For this purpose, sets of continuous or discontinuous stiffness profiles through the thickness of the cuticle were mathematically described. The obtained profiles were assigned to models developed based on the cuticle of three insect species with different geometries and layer configurations. The models were then used to simulate the mechanical behaviour of insect cuticles subjected to nanoindentation experiments. Our results show that FE models with discontinuous exponential stiffness gradients along their thickness were able to predict the stress and deformation states in insect cuticle very well. Our results further suggest that, for more accurate measurements and interpretation of nanoindentation test data, the ratio of the indentation depth to cuticle thickness should be limited to 7% rather than the traditional '10% rule'. The results of this study thus might be useful to provide a deeper insight into the biomechanical consequences of the distinct material distribution in insect cuticle and also to form a basis for more realistic modelling of this complex natural composite. © 2017 The Author(s).

Avoiding a bad apple: Insect pollination enhances fruit quality and economic value☆

Science.gov (United States)

Garratt, M.P.D.; Breeze, T.D.; Jenner, N.; Polce, C.; Biesmeijer, J.C.; Potts, S.G.

2014-01-01

Insect pollination is important for food production globally and apples are one of the major fruit crops which are reliant on this ecosystem service. It is fundamentally important that the full range of benefits of insect pollination to crop production are understood, if the costs of interventions aiming to enhance pollination are to be compared against the costs of the interventions themselves. Most previous studies have simply assessed the benefits of pollination to crop yield and ignored quality benefits and how these translate through to economic values. In the present study we examine the influence of insect pollination services on farmgate output of two important UK apple varieties; Gala and Cox. Using field experiments, we quantify the influence of insect pollination on yield and importantly quality and whether either may be limited by sub-optimal insect pollination. Using an expanded bioeconomic model we value insect pollination to UK apple production and establish the potential for improvement through pollination service management. We show that insects are essential in the production of both varieties of apple in the UK and contribute a total of £36.7 million per annum, over £6 million more than the value calculated using more conventional dependence ratio methods. Insect pollination not only affects the quantity of production but can also have marked impacts on the quality of apples, influencing size, shape and effecting their classification for market. These effects are variety specific however. Due to the influence of pollination on both yield and quality in Gala, there is potential for insect pollination services to improve UK output by up to £5.7 million per annum. Our research shows that continued pollinator decline could have serious financial implications for the apple industry but there is considerable scope through management of wild pollinators or using managed pollinator augmentation, to improve the quality of production. Furthermore, we

Avoiding a bad apple: Insect pollination enhances fruit quality and economic value.

Science.gov (United States)

Garratt, M P D; Breeze, T D; Jenner, N; Polce, C; Biesmeijer, J C; Potts, S G

2014-02-01

Insect pollination is important for food production globally and apples are one of the major fruit crops which are reliant on this ecosystem service. It is fundamentally important that the full range of benefits of insect pollination to crop production are understood, if the costs of interventions aiming to enhance pollination are to be compared against the costs of the interventions themselves. Most previous studies have simply assessed the benefits of pollination to crop yield and ignored quality benefits and how these translate through to economic values. In the present study we examine the influence of insect pollination services on farmgate output of two important UK apple varieties; Gala and Cox. Using field experiments, we quantify the influence of insect pollination on yield and importantly quality and whether either may be limited by sub-optimal insect pollination. Using an expanded bioeconomic model we value insect pollination to UK apple production and establish the potential for improvement through pollination service management. We show that insects are essential in the production of both varieties of apple in the UK and contribute a total of £36.7 million per annum, over £6 million more than the value calculated using more conventional dependence ratio methods. Insect pollination not only affects the quantity of production but can also have marked impacts on the quality of apples, influencing size, shape and effecting their classification for market. These effects are variety specific however. Due to the influence of pollination on both yield and quality in Gala, there is potential for insect pollination services to improve UK output by up to £5.7 million per annum. Our research shows that continued pollinator decline could have serious financial implications for the apple industry but there is considerable scope through management of wild pollinators or using managed pollinator augmentation, to improve the quality of production. Furthermore, we

Evolutionary conservation and changes in insect TRP channels

OpenAIRE

Tominaga Makoto; Kohno Keigo; Sokabe Takaaki; Matsuura Hironori; Kadowaki Tatsuhiko

2009-01-01

Abstract Background TRP (Transient Receptor Potential) channels respond to diverse stimuli and thus function as the primary integrators of varied sensory information. They are also activated by various compounds and secondary messengers to mediate cell-cell interactions as well as to detect changes in the local environment. Their physiological roles have been primarily characterized only in mice and fruit flies, and evolutionary studies are limited. To understand the evolution of insect TRP c...

PSR experience with beam losses, instabilities and space charge effects

International Nuclear Information System (INIS)

Macek, Robert J.

1998-01-01

Average current from the PSR has been limited to ∼70 μA at 20 Hz by beam losses of 0.4 to 0.5 μA which arise from two principal causes, production of H 0 excited states and stored-beam scattering in the stripper foil. To reduce beam losses, an upgrade from the two-step H 0 injection to direct H - injection is underway and will be completed in 1998. Peak intensity from the PSR is limited by a strong instability that available evidence indicates is the two-stream e-p instability. New evidence for the e-p hypothesis is presented. At operating intensities, the incoherent space charge tune shift depresses both horizontal and vertical tunes past the integer without additional beam loss although some intensity-dependent emittance growth is observed

Allergenicity and cross-reactivity of booklice (Liposcelis bostrichophila): a common household insect pest in Japan.

Science.gov (United States)

Fukutomi, Yuma; Kawakami, Yuji; Taniguchi, Masami; Saito, Akemi; Fukuda, Azumi; Yasueda, Hiroshi; Nakazawa, Takuya; Hasegawa, Maki; Nakamura, Hiroyuki; Akiyama, Kazuo

2012-01-01

Booklice (Liposcelis bostrichophila) are a common household insect pest distributed worldwide. Particularly in Japan, they infest 'tatami' mats and are the most frequently detected insect among all detectable insects, present at a frequency of about 90% in dust samples. Although it has been hypothesized that they are an important indoor allergen, studies on their allergenicity have been limited. To clarify the allergenicity of booklice and the cross-reactivity of this insect allergen with allergens of other insects, patients sensitized to booklice were identified from 185 Japanese adults with allergic asthma using skin tests and IgE-ELISA. IgE-inhibition analysis, immunoblotting and immunoblotting-inhibition analysis were performed using sera from these patients. Allergenic proteins contributing to specific sensitization to booklice were identified by two-dimensional electrophoresis and two-dimensional immunoblotting. The booklouse-specific IgE antibody was detected in sera from 41 patients (22% of studied patients). IgE inhibition analysis revealed that IgE reactivity to the booklouse allergen in the sera from one third of booklouse-sensitized patients was not inhibited by preincubation with extracts from any other environmental insects in this study. Immunoblotting identified a 26-kD protein from booklouse extract as the allergenic protein contributing to specific sensitization to booklice. The amino acid sequence of peptide fragments of this protein showed no homology to those of previously described allergenic proteins, indicating that this protein is a new allergen. Sensitization to booklice was relatively common and specific sensitization to this insect not related to insect panallergy was indicated in this population. Copyright © 2011 S. Karger AG, Basel.

Thermal instabilities in the edge region of reversed-field pinches

International Nuclear Information System (INIS)

Goedert, J.; Mondt, J.P.

1984-04-01

Thermal stability of the edge region of reversed-field pinch configurations is analyzed within the context of a two-fluid model. Two major sources of instability are identified in combination with a parallel electric field: either an electron temperature gradient and/or a density gradient that leads to rapid growth (of several to many ohmic heating rates) over a region of several millimeters around the mode-rational surfaces in the edge region. The basic signature of both instabilities is electrostatic. In the case of the density gradient mode, the signature relies on the effects of electron compressibility, whereas the temperature gradient mode can be identified as the current-convective instability by taking the limit of zero diamagnetic drift, density gradient, thermal force, drift heat flux, and electron compressibility

The longitudinal wall impedance instability in a heavy-ion fusion driver

International Nuclear Information System (INIS)

Callahan, D.A.; Langdon, A.B.; Friedman, A.; Haber, I.

1997-01-01

For more than ten years [J. Bisognano, I. Haber, L. Smith, IEEE Trans. Nucl. Sci. NS-30, 2501 (1983)], the longitudinal wall impedance instability was thought to be a serious threat to the success of heavy-ion driven inertial confinement fusion. This instability is a open-quotes resistive wallclose quotes instability, driven by the impedance of the induction modules used to accelerate the beam. Early estimates of the instability growth rate predicted tens of e-folds due to the instability which would modulate the current and increase the longitudinal momentum spread and prevent focusing the ion beam on the small spot needed at the target. We have simulated this instability using an r-z particle-in-cell code which includes a model for the module impedance. These simulations, using driver parameters, show that growth due to the instability is smaller than in previous calculations. We have seen that growth is mainly limited to one head to tail transit by a space-charge wave. In addition, the capacitive component of the module impedance, which was neglected in the early work of Lee [E. P. Lee, Proc. Linear Accelerator Conference, (UCRL-86452), Santa Fe, NM, 1981] significantly reduces the growth rate. We have also included in the simulation intermittently applied axial confining fields which are thought to be the major source of perturbations to seed the longitudinal instability. Simulations show the beam can adjust to a systematic error in the longitudinal confining fields while a random error excites the most unstable wavelength of the instability. These simulations show that the longitudinal instability must be taken into account in a driver design, but it is not the major factor it was once thought to be. copyright 1997 American Institute of Physics

Joint Instability and Osteoarthritis

Directory of Open Access Journals (Sweden)

Darryl Blalock

2015-01-01

Full Text Available Joint instability creates a clinical and economic burden in the health care system. Injuries and disorders that directly damage the joint structure or lead to joint instability are highly associated with osteoarthritis (OA. Thus, understanding the physiology of joint stability and the mechanisms of joint instability-induced OA is of clinical significance. The first section of this review discusses the structure and function of major joint tissues, including periarticular muscles, which play a significant role in joint stability. Because the knee, ankle, and shoulder joints demonstrate a high incidence of ligament injury and joint instability, the second section summarizes the mechanisms of ligament injury-associated joint instability of these joints. The final section highlights the recent advances in the understanding of the mechanical and biological mechanisms of joint instability-induced OA. These advances may lead to new opportunities for clinical intervention in the prevention and early treatment of OA.

Lessons from non-Abelian plasma instabilities in two spatial dimensions

International Nuclear Information System (INIS)

Arnold, Peter; Leang, P.-S.

2007-01-01

Plasma instabilities can play a fundamental role in quark-gluon plasma equilibration in the high energy (weak coupling) limit. Early simulations of the evolution of plasma instabilities in non-Abelian gauge theory, performed in one spatial dimension, found behavior qualitatively similar to traditional QED plasmas. Later simulations of the fully three-dimensional theory found different behavior, unlike traditional QED plasmas. To shed light on the origin of this difference, we study the intermediate case of two spatial dimensions. Depending on how the 'two-dimensional' theory is formulated, we can obtain either behavior

Prostaglandins and their receptors in insect biology

Directory of Open Access Journals (Sweden)

David eStanley

2011-12-01

Full Text Available We treat the biological significance of prostaglandins (PGs and their known receptors in insect biology. PGs and related eicosanoids are oxygenated derivatives of arachidonic acid (AA and two other C20 polyunsaturated fatty acids. PGs are mostly appreciated in the context of biomedicine, but a growing body of literature indicates the biological significance of these compounds extends throughout the animal kingdom, and possibly beyond. PGs act in several crucial areas of insect biology. In reproduction, a specific PG, PGE2, releases oviposition behavior in most crickets and a few other insect species; PGs also mediate events in egg development in some species, which may represent all insects. PGs play major roles in modulating fluid secretion in Malpighian tubules, rectum and salivary glands, although, again, this has been studied in only a few insect species that may represent the Class. Insect immunity is a very complex defense system. PGs and other eicosanoids mediate a large number of immune reactions to infection and invasion. The actions of most PGs are mediated by specific receptors. Biomedical research has discovered a great deal of knowledge about PG receptors in mammals, including their structures, pharmacology, molecular biology and cellular locations. Studies of PG receptors in insects lag behind the biomedical background, however, recent results hold the promise of accelerated research in this area. A PG receptor has been identified in a class of lepidopteran hemocytes and experimentally linked to the release of prophenoloxidase. We conclude that research into PGs and their receptors in insects will lead to important advances in our understanding of insect biology.

A variational approach to parametric instabilities in inhomogeneous plasmas

Energy Technology Data Exchange (ETDEWEB)

Afeyan, B.B.

1993-12-31

A variational principle is constructed for the pump strength of a three-wave parametric instability in a spatially nonuniform medium. Using this expression together with appropriate trial functions, analytic estimates of the growth rate of the most unstable mode of a given parametric instability may be calculated. The usefullness of the variational method is first demonstrated on the Rosenbluth model problem with a power-law phase-mismatch, followed by a treatment of the Liu, Rosenbluth, and White sidescattering model equation. Two particular instabilities which are of interest in laser fusion and laser-plasma interaction experiments are treated next. These are Stimulated Raman Scattering and Two-Plasmon Decay. Various incidence and scattering geometries, and different density profiles are considered. Previously known results are reproduced in a unified manner and extended to cases where the usual local-expansion techniques do not apply. In particular, using the variational approach, the growth rate of the Two-Plasmon Decay instability occurring at or anywhere below the apex of a parabolic density profile is obtained for the first time. Similarly, Stimulated Raman Scattering from a density extremum at or anywhere below quarter critical, and for all scattering angles from backscattering to sidescattering inclusively is considered for the first time. The limit where the Two-Plasmon Decay and Stimulated Raman Scattering instabilities merge and become indistinguishable is also treated.

Microbiology of processed edible insect products - Results of a preliminary survey.

Science.gov (United States)

Grabowski, Nils Th; Klein, Günter

2017-02-21

Little is known of the microbiology of processed insect products. The present survey analysed a total of n=38 samples of deep-fried and spiced (Acheta domesticus, Locusta migratoria, and Omphisa fuscidentalis), cooked in soy sauce ("tsukudani"; Oxya yezoensis, Vespula flaviceps, and Bombyx mori), dried (A. domesticus, L. migatoria, Alphitobius diaperinus, Tenebrio molitor, B. mori, Hermetia illucens, and Musca domestica), powdered (H. illucens, T. molitor) and other (incl. deep-frozen B. mori and honeybee pollen) insect products microbiologically (total bacterial count [TBC], Enterobacteriaceae, staphylococci, bacilli, and yeasts and moulds counts, salmonellae, Listeria monocytogenes, and Escherichia coli). Although each product type revealed a microbiological profile of its own, dried and powdered insects ("class I") displayed markedly higher counts than the deep-fried and cooked ones ("class II"). Thresholds between class I and II products were estimated at 4.0 (TBC), 1.0 (Enterobacteriaceae, yeasts and moulds), 2.5 (staphylococci), and 3.0lgcfu/g (bacilli). All samples were negative for salmonellae, L. monocytogenes, E. coli and Stapyhlococcus aureus, but dried and powdered insects, as well as pollen, contained B. cereus, coliforms, Serratia liquefaciens, Listeria ivanovii, Mucor spp., Aspergillus spp., Penicillium spp., and Cryptococcus neoformans. Comparing the results with the hygiene criteria for edible insects proposed by Belgium and the Netherlands, class I products failed to comply with many bacterial count limits despite the absence of classical food pathogens. Therefore, class I products should always be consumed after another heating step as indicated by the manufacturer, until drying techniques are able to ensure lower bacterial counts. Copyright © 2016 Elsevier B.V. All rights reserved.

Modern insect control: Nuclear techniques and biotechnology

International Nuclear Information System (INIS)

1988-01-01

The Symposium dealt primarily with genetic methods of insect control, including sterile insect technique (SIT), F 1 sterility, compound chromosomes, translocations and conditional lethals. Research and development activities on various aspects of these control technologies were reported by participants during the Symposium. Of particular interest was development of F 1 sterility as a practical method of controlling pest Lepidoptera. Genetic methods of insect control are applicable only on an area wide basis. They are species specific and thus do not reduce populations of beneficial insects or cause other environmental problems. Other papers presented reported on the potential use of radiation as a quarantine treatment for commodities in international trade and the use of radioisotopes as ''tags'' in studying insects

Regions identity between the genome of vertebrates and non-retroviral families of insect viruses

Directory of Open Access Journals (Sweden)

Fan Gaowei

2011-11-01

Full Text Available Abstract Background The scope of our understanding of the evolutionary history between viruses and animals is limited. The fact that the recent availability of many complete insect virus genomes and vertebrate genomes as well as the ability to screen these sequences makes it possible to gain a new perspective insight into the evolutionary interaction between insect viruses and vertebrates. This study is to determine the possibility of existence of sequence identity between the genomes of insect viruses and vertebrates, attempt to explain this phenomenon in term of genetic mobile element, and try to investigate the evolutionary relationship between these short regions of identity among these species. Results Some of studied insect viruses contain variable numbers of short regions of sequence identity to the genomes of vertebrate with nucleotide sequence length from 28 bp to 124 bp. They are found to locate in multiple sites of the vertebrate genomes. The ontology of animal genes with identical regions involves in several processes including chromatin remodeling, regulation of apoptosis, signaling pathway, nerve system development and some enzyme-like catalysis. Phylogenetic analysis reveals that at least some short regions of sequence identity in the genomes of vertebrate are derived the ancestral of insect viruses. Conclusion Short regions of sequence identity were found in the vertebrates and insect viruses. These sequences played an important role not only in the long-term evolution of vertebrates, but also in promotion of insect virus. This typical win-win strategy may come from natural selection.

Insects and other invertebrates

Science.gov (United States)

John R. Jones; Norbert V. DeByle; Diane M. Bowers

1985-01-01

Quaking aspen throughout its range appears to be host to several insect and other invertebrate pests (fig. 1). It is a short-lived species that is palatable to a large variety of animals. Furniss and Carolin (1977) listed 33 insect species that use aspen as a food source. Some are quite damaging and may kill otherwise healthy stands of aspen; others feed on weakened or...

How Insects Survive Winter in the Midwest

Science.gov (United States)

Understanding how insects cope with cold temperatures can not only help entomologists more accurately forecast when and where insects are active, but it may also help us understand how climate change will influence insect pests. This newsletter article provides a comprehensive overview of how Midwes...

Microbiological Load of Edible Insects Found in Belgium

OpenAIRE

Rudy Caparros Megido; Sandrine Desmedt; Christophe Blecker; François Béra; Éric Haubruge; Taofic Alabi; Frédéric Francis

2017-01-01

Edible insects are gaining more and more attention as a sustainable source of animal protein for food and feed in the future. In Belgium, some insect products can be found on the market, and consumers are sourcing fresh insects from fishing stores or towards traditional markets to find exotic insects that are illegal and not sanitarily controlled. From this perspective, this study aims to characterize the microbial load of edible insects found in Belgium (i.e., fresh mealworms and house crick...

Jeans Instability of the Self-Gravitating Viscoelastic Ferromagnetic Cylinder with Axial Nonuniform Rotation and Magnetic Field

Science.gov (United States)

Dhiman, Joginder Singh; Sharma, Rajni

2017-12-01

The effects of nonuniform rotation and magnetic field on the instability of a self gravitating infinitely extending axisymmetric cylinder of viscoelastic ferromagnetic medium have been studied using the Generalised Hydrodynamic (GH) model. The non-uniform magnetic field and rotation are acting along the axial direction of the cylinder and the propagation of the wave is considered along the radial direction, while the ferrofluid magnetization is taken collinear with the magnetic field. A general dispersion relation representing magnetization, magnetic permeability and viscoelastic relaxation time parameters is obtained using the normal mode analysis method in the linearized perturbation equation system. Jeans criteria which represent the onset of instability of self gravitating medium are obtained under the limits; when the medium behaves like a viscous liquid (strongly coupled limit) and a Newtonian liquid (weakly coupled limit). The effects of various parameters on the Jeans instability criteria and on the growth rate of self gravitating viscoelastic ferromagnetic medium have been discussed. It is found that the magnetic polarizability due to ferromagnetization of medium marginalizes the effect of non-uniform magnetic field on the Jeans instability, whereas the viscoelasticity of the medium has the usual stabilizing effect on the instability of the system. Further, it is found that the cylindrical geometry is more stable than the Cartesian one. The variation of growth rate against the wave number and radial distance has been depicted graphically.

Love Games that Insects Play

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 1. Love Games that Insects Play - The Evolution of Sexual Behaviours in Insects ... Author Affiliations. K N Ganeshaiah1. Department of Genetics & Plant Breeding University of Agricultural Sciences, GKVK Bangalore 560 065, India ...

Theory of the corrugation instability of a piston-driven shock wave.

Science.gov (United States)

Bates, J W

2015-01-01

We analyze the two-dimensional stability of a shock wave driven by a steadily moving corrugated piston in an inviscid fluid with an arbitrary equation of state. For h≤-1 or h>h(c), where h is the D'yakov parameter and h(c) is the Kontorovich limit, we find that small perturbations on the shock front are unstable and grow--at first quadratically and later linearly--with time. Such instabilities are associated with nonequilibrium fluid states and imply a nonunique solution to the hydrodynamic equations. The above criteria are consistent with instability limits observed in shock-tube experiments involving ionizing and dissociating gases and may have important implications for driven shocks in laser-fusion, astrophysical, and/or detonation studies.

The influence of dual-recycling on parametric instabilities at Advanced LIGO

International Nuclear Information System (INIS)

Green, A C; Brown, D D; Dovale-Álvarez, M; Collins, C; Miao, H; Mow-Lowry, C M; Freise, A

2017-01-01

Laser interferometers with high circulating power and suspended optics, such as the LIGO gravitational wave detectors, experience an optomechanical coupling effect known as a parametric instability : the runaway excitation of a mechanical resonance in a mirror driven by the optical field. This can saturate the interferometer sensing and control systems and limit the observation time of the detector. Current mitigation techniques at the LIGO sites are successfully suppressing all observed parametric instabilities, and focus on the behaviour of the instabilities in the Fabry–Perot arm cavities of the interferometer, where the instabilities are first generated. In this paper we model the full dual-recycled Advanced LIGO design with inherent imperfections. We find that the addition of the power- and signal-recycling cavities shapes the interferometer response to mechanical modes, resulting in up to four times as many peaks. Changes to the accumulated phase or Gouy phase in the signal-recycling cavity have a significant impact on the parametric gain, and therefore which modes require suppression. (paper)

On the identification of instabilities with neural networks on JET

International Nuclear Information System (INIS)

Murari, A.; Arena, P.; Buscarino, A.; Fortuna, L.; Iachello, M.

2013-01-01

JET plasmas are affected by various instabilities, which can be particularly dangerous in high performance discharges. An identification method, based on the use of advanced neural networks, called Recurrent Neural Networks (RNNs), has been applied to ELMs. The potential of the recurrent networks to identify the dynamics of the instabilities has been first tested using synthetic data. The networks have then been applied to JET experimental signals. An appropriate selection of the networks topology allows identifying quite well the time evolution of the edge temperature and of the magnetic fields, considered the best indicators of the ELMs. A quite limited number of periodic oscillations are used to train the networks, which then manage to follow quite well the dynamics of the instabilities, in a recurrent configuration on one of the inputs. The time evolution of the aforementioned signals, also during intervals not used in the training and never seen by the networks, are properly reproduced. A careful analysis of the various terms in the RNNs has the potential to give clear indications about the nature of these instabilities and their dynamical behaviour

Uncertainty Instability Risk Analysis of High Concrete Arch Dam Abutments

Directory of Open Access Journals (Sweden)

Xin Cao

2017-01-01

Full Text Available The uncertainties associated with concrete arch dams rise with the increased height of dams. Given the uncertainties associated with influencing factors, the stability of high arch dam abutments as a fuzzy random event was studied. In addition, given the randomness and fuzziness of calculation parameters as well as the failure criterion, hazard point and hazard surface uncertainty instability risk ratio models were proposed for high arch dam abutments on the basis of credibility theory. The uncertainty instability failure criterion was derived through the analysis of the progressive instability failure process on the basis of Shannon’s entropy theory. The uncertainties associated with influencing factors were quantized by probability or possibility distribution assignments. Gaussian random theory was used to generate random realizations for influence factors with spatial variability. The uncertainty stability analysis method was proposed by combining the finite element analysis and the limit equilibrium method. The instability risk ratio was calculated using the Monte Carlo simulation method and fuzzy random postprocessing. Results corroborate that the modeling approach is sound and that the calculation method is feasible.

Numerical modeling of flow boiling instabilities using TRACE

International Nuclear Information System (INIS)

Kommer, Eric M.

2015-01-01

Highlights: • TRACE was used to realistically model boiling instabilities in single and parallel channel configurations. • Model parameters were chosen to exactly mimic other author’s work in order to provide for direct comparison of results. • Flow stability maps generated by the model show unstable flow at operating points similar to other authors. • The method of adjudicating when a flow is “unstable” is critical in this type of numerical study. - Abstract: Dynamic flow instabilities in two-phase systems are a vitally important area of study due to their effects on a great number of industrial applications, including heat exchangers in nuclear power plants. Several next generation nuclear reactor designs incorporate once through steam generators which will exhibit boiling flow instabilities if not properly designed or when operated outside design limits. A number of numerical thermal hydraulic codes attempt to model instabilities for initial design and for use in accident analysis. TRACE, the Nuclear Regulatory Commission’s newest thermal hydraulic code is used in this study to investigate flow instabilities in both single and dual parallel channel configurations. The model parameters are selected as to replicate other investigators’ experimental and numerical work in order to provide easy comparison. Particular attention is paid to the similarities between analysis using TRACE Version 5.0 and RELAP5/MOD3.3. Comparison of results is accomplished via flow stability maps non-dimensionalized via the phase change and subcooling numbers. Results of this study show that TRACE does indeed model two phase flow instabilities, with the transient response closely mimicking that seen in experimental studies. When compared to flow stability maps generated using RELAP, TRACE shows similar results with differences likely due to the somewhat qualitative criteria used by various authors to determine when the flow is truly unstable

Diversity, evolution and medical applications of insect antimicrobial peptides

Science.gov (United States)

Mylonakis, Eleftherios; Podsiadlowski, Lars; Muhammed, Maged

2016-01-01

Antimicrobial peptides (AMPs) are short proteins with antimicrobial activity. A large portion of known AMPs originate from insects, and the number and diversity of these molecules in different species varies considerably. Insect AMPs represent a potential source of alternative antibiotics to address the limitation of current antibiotics, which has been caused by the emergence and spread of multidrug-resistant pathogens. To get more insight into AMPs, we investigated the diversity and evolution of insect AMPs by mapping their phylogenetic distribution, allowing us to predict the evolutionary origins of selected AMP families and to identify evolutionarily conserved and taxon-specific families. Furthermore, we highlight the use of the nematode Caenorhabditis elegans as a whole-animal model in high-throughput screening methods to identify AMPs with efficacy against human pathogens, including Acinetobacter baumanii and methicillin-resistant Staphylococcus aureus. We also discuss the potential medical applications of AMPs, including their use as alternatives for conventional antibiotics in ectopic therapies, their combined use with antibiotics to restore the susceptibility of multidrug-resistant pathogens, and their use as templates for the rational design of peptidomimetic drugs that overcome the disadvantages of therapeutic peptides. The article is part of the themed issue ‘Evolutionary ecology of arthropod antimicrobial peptides’. PMID:27160593

Diversity, evolution and medical applications of insect antimicrobial peptides.

Science.gov (United States)

Mylonakis, Eleftherios; Podsiadlowski, Lars; Muhammed, Maged; Vilcinskas, Andreas

2016-05-26

Antimicrobial peptides (AMPs) are short proteins with antimicrobial activity. A large portion of known AMPs originate from insects, and the number and diversity of these molecules in different species varies considerably. Insect AMPs represent a potential source of alternative antibiotics to address the limitation of current antibiotics, which has been caused by the emergence and spread of multidrug-resistant pathogens. To get more insight into AMPs, we investigated the diversity and evolution of insect AMPs by mapping their phylogenetic distribution, allowing us to predict the evolutionary origins of selected AMP families and to identify evolutionarily conserved and taxon-specific families. Furthermore, we highlight the use of the nematode Caenorhabditis elegans as a whole-animal model in high-throughput screening methods to identify AMPs with efficacy against human pathogens, including Acinetobacter baumanii and methicillin-resistant Staphylococcus aureus We also discuss the potential medical applications of AMPs, including their use as alternatives for conventional antibiotics in ectopic therapies, their combined use with antibiotics to restore the susceptibility of multidrug-resistant pathogens, and their use as templates for the rational design of peptidomimetic drugs that overcome the disadvantages of therapeutic peptides.The article is part of the themed issue 'Evolutionary ecology of arthropod antimicrobial peptides'. © 2016 The Authors.

Wakefields and Instabilities in Linear Accelerators

CERN Document Server

Ferrario, M.; Palumbo, L.

2014-12-19

When a charged particle travels across the vacuum chamber of an accelerator, it induces electromagnetic fields, which are left mainly behind the generating particle. These electromagnetic fields act back on the beam and influence its motion. Such an interaction of the beam with its surro undings results in beam energy losses, alters the shape of the bunches, and shifts the betatron and synchrotron frequencies. At high beam current the fields can even lead to instabilities, thus limiting the performance of the accelerator in terms of beam quality and current intensity. We discuss in this lecture the general features of the electromagnetic fields, introducing the concepts of wakefields and giving a few simple examples in cylindrical geometry. We then show the effect of the wakefields on the dynamics of a beam in a linac, dealing in particular with the beam breakup instability and how to cure it.

Numerical Studies of Electromagnetic Instabilities in Intense Charged Particle Beams with Large Energy Anisotropy

CERN Document Server

Startsev, Edward; Lee, Wei-li

2005-01-01

In intense charged particle beams with large energy anisotropy, free energy is available to drive transverse electromagnetic Weibel-type instabilities. Such slow-wave transverse electromagnetic instabilities can be described by the so-called Darwin model, which neglects the fast-wave portion of the displacement current. The Weibel instability may also lead to an increase in the longitudinal velocity spread, which would make the focusing of the beam difficult and impose a limit on the minimum spot size achievable in heavy ion fusion experiments. This paper reports the results of recent numerical studies of the Weibel instability using the Beam Eigenmode And Spectra (bEASt) code for space-charge-dominated, low-emittance beams with large tune depression. To study the nonlinear stage of the instability, the Darwin model is being developed and incorporated into the Beam Equilibrium Stability and Transport(BEST) code.

[Study on essential oils of medicinal plants in insect repellent].

Science.gov (United States)

Zhao, Hong-Zheng; Luo, Jiao-Yang; Liu, Qiu-Tao; Lv, Ze-Liang; Yang, Shi-Hai; Yang, Mei-Hua

2016-01-01

Mosquitoes are seriously harmful to human health for transmitting some mortal diseases. Among the methods of mosquito control, synthetical insecticides are the most popular. However, as a result of longterm use of these insecticides, high resistant mosquitos and heavy environmental pollution appear. Thus, eco-friendly prevention measures are taken into the agenda. Essential oils extracted from medicinal plants have repellent and smoked killing effects on mosquitoes. With abundant medical plants resources and low toxicity, they have the potential of being developed as a new type of mosquito and insect repellent agent. The recent application advances of essential oils of medicinal plants in insect repellent and its application limitations are overviewed. This review will provide references for the future development and in-depth study of essential oils. Copyright© by the Chinese Pharmaceutical Association.

External Insect Morphology: A Negative Factor in Attitudes toward Insects and Likelihood of Incorporation in Future Science Education Settings

Science.gov (United States)

Wagler, Ron; Wagler, Amy

2012-01-01

This study investigated if the external morphology of an insect had a negative effect on United States (US) preservice elementary teacher's attitudes toward insects and beliefs concerning the likelihood of incorporating insects into future science education settings. 270 US kindergarten through sixth grade preservice elementary teachers…

Size-dependent axisymmetric vibration of functionally graded circular plates in bifurcation/limit point instability

Science.gov (United States)

Ashoori, A. R.; Vanini, S. A. Sadough; Salari, E.

2017-04-01

In the present paper, vibration behavior of size-dependent functionally graded (FG) circular microplates subjected to thermal loading are carried out in pre/post-buckling of bifurcation/limit-load instability for the first time. Two kinds of frequently used thermal loading, i.e., uniform temperature rise and heat conduction across the thickness direction are considered. Thermo-mechanical material properties of FG plate are supposed to vary smoothly and continuously throughout the thickness based on power law model. Modified couple stress theory is exploited to describe the size dependency of microplate. The nonlinear governing equations of motion and associated boundary conditions are extracted through generalized form of Hamilton's principle and von-Karman geometric nonlinearity for the vibration analysis of circular FG plates including size effects. Ritz finite element method is then employed to construct the matrix representation of governing equations which are solved by two different strategies including Newton-Raphson scheme and cylindrical arc-length method. Moreover, in the following a parametric study is accompanied to examine the effects of the several parameters such as material length scale parameter, temperature distributions, type of buckling, thickness to radius ratio, boundary conditions and power law index on the dimensionless frequency of post-buckled/snapped size-dependent FG plates in detail. It is found that the material length scale parameter and thermal loading have a significant effect on vibration characteristics of size-dependent circular FG plates.

Diversity in protein glycosylation among insect species.

Directory of Open Access Journals (Sweden)

Gianni Vandenborre

Full Text Available BACKGROUND: A very common protein modification in multicellular organisms is protein glycosylation or the addition of carbohydrate structures to the peptide backbone. Although the Class of the Insecta is the largest animal taxon on Earth, almost all information concerning glycosylation in insects is derived from studies with only one species, namely the fruit fly Drosophila melanogaster. METHODOLOGY/PRINCIPAL FINDINGS: In this report, the differences in glycoproteomes between insects belonging to several economically important insect orders were studied. Using GNA (Galanthus nivalis agglutinin affinity chromatography, different sets of glycoproteins with mannosyl-containing glycan structures were purified from the flour beetle (Tribolium castaneum, the silkworm (Bombyx mori, the honeybee (Apis mellifera, the fruit fly (D. melanogaster and the pea aphid (Acyrthosiphon pisum. To identify and characterize the purified glycoproteins, LC-MS/MS analysis was performed. For all insect species, it was demonstrated that glycoproteins were related to a broad range of biological processes and molecular functions. Moreover, the majority of glycoproteins retained on the GNA column were unique to one particular insect species and only a few glycoproteins were present in the five different glycoprotein sets. Furthermore, these data support the hypothesis that insect glycoproteins can be decorated with mannosylated O-glycans. CONCLUSIONS/SIGNIFICANCE: The results presented here demonstrate that oligomannose N-glycosylation events are highly specific depending on the insect species. In addition, we also demonstrated that protein O-mannosylation in insect species may occur more frequently than currently believed.

Insect Data

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Records of past temperature and environment derived from beetle and other insect fossils. Parameter keywords describe what was measured in this data set. Additional...

Kinetic instabilities in the solar wind driven by temperature anisotropies

Science.gov (United States)

Yoon, Peter H.

2017-12-01

The present paper comprises a review of kinetic instabilities that may be operative in the solar wind, and how they influence the dynamics thereof. The review is limited to collective plasma instabilities driven by the temperature anisotropies. To limit the scope even further, the discussion is restricted to the temperature anisotropy-driven instabilities within the model of bi-Maxwellian plasma velocity distribution function. The effects of multiple particle species or the influence of field-aligned drift will not be included. The field-aligned drift or beam is particularly prominent for the solar wind electrons, and thus ignoring its effect leaves out a vast portion of important physics. Nevertheless, for the sake of limiting the scope, this effect will not be discussed. The exposition is within the context of linear and quasilinear Vlasov kinetic theories. The discussion does not cover either computer simulations or data analyses of observations, in any systematic manner, although references will be made to published works pertaining to these methods. The scientific rationale for the present analysis is that the anisotropic temperatures associated with charged particles are pervasively detected in the solar wind, and it is one of the key contemporary scientific research topics to correctly characterize how such anisotropies are generated, maintained, and regulated in the solar wind. The present article aims to provide an up-to-date theoretical development on this research topic, largely based on the author's own work.

Synthetic analogues of natural semiochemicals as promising insect control agents

International Nuclear Information System (INIS)

Ujvary, Istvan; Toth, Miklos; Guerin, Patrick

2000-01-01

After decades of research and development, insect pheromones and other semiochemicals became indispensable tools of ecologically based agricultural pest and disease vector management programmes with main uses as: 1) detection and population monitoring of emerging and migrating insects, 2) mass trapping of insects, 3) combined formulation of semiochemicals and insecticides ('lure-and-kill'), and 4) mating disruption with specially formulated pheromone components. In spite of their demonstrated safety and biodegradability, the direct application of these semiochemicals for pest control has not fulfilled initial expectations. Nonetheless considerable field experience has been accumulated (Carde and Minks 1995). Evidently, two important factors limit the practical potential of these substances: 1) inherent in their particular mode of action, semiochemicals, especially pheromones, are effectively cleared by specific enzymes in the insect antennae, and 2) some of these compounds contain labile functional moieties that are prone to degradation (oxidation, isomerisation and polymerisation) under field conditions. Appropriate chemical modifications of these natural compounds, however, can circumvent these problems by providing synthetic analogues (sometimes also called parapheromones or antipheromones; for early studies, see Roelofs and Comeau 1971, Payne et al. 1973) which in ideal cases are not only more potent and environmentally acceptable but more economical as well. It should also be mentioned that many effective attractants have been discovered through the empirical screening of synthetic chemicals, some of which have actually turned out to be structural relatives of natural semiochemicals of the particular insect. In this paper, selected case studies of analogues of sex pheromones and kairomones will be presented. The examples from our work include nitrile bioisosteres of labile aldehyde pheromone components of the cranberry girdler moth, Chrysoteuchia topiaria

Effects of joint mobilization on chronic ankle instability: a randomized controlled trial.

Science.gov (United States)

Cruz-Díaz, David; Lomas Vega, Rafael; Osuna-Pérez, Maria Catalina; Hita-Contreras, Fidel; Martínez-Amat, Antonio

2015-01-01

To evaluate the effects of joint mobilization, in which movement is applied to the ankle's dorsiflexion range of motion, on dynamic postural control and on the self-reported instability of patients with chronic ankle instability (CAI). A double-blind, placebo-controlled, randomized trial with repeated measures and a follow-up period. Ninety patients with a history of recurrent ankle sprain, self-reported instability, and a limited dorsiflexion range of motion, were randomly assigned to either the intervention group (Joint Mobilizations, 3 weeks, two sessions per week) the placebo group (Sham Mobilizations, same duration as joint mobilization) or the control group, with a 6 months follow-up. Dorsiflexion Range of Motion (DFROM), Star Excursion Balance Test (SEBT) and CAI Tool (CAIT) were outcome measures. A separate 3 × 4 mixed model analysis of variance was performed to examine the effect of treatment conditions and time, and intention-to-treat (ITT) analysis was applied to evaluate the effect of the independent variable. The application of joint mobilization resulted in better scores of DFROM, CAIT, and SEBTs in the intervention group when compared with the placebo or the control groups (p ankle DFROM, postural control, and self-reported instability. These results suggest that joint mobilization could be applied to patients with recurrent ankle sprain to help restore their functional stability. Implications for Rehabilitation Functional instability is a very common sequela in patients with CAI, resulting in reduced quality of living due to the limitations it imposes on daily life activities. The mobilization with movement technique presented by Mulligan, and based on the joint mobilization accompanied by active movement, appears as a valuable tool to be employed by physical therapists to restore ankle function after a recurrent ankle sprain history. ROM restriction, subjective feeling of instability and dynamic postural control are benefiting from the joint

Allergy to insect stings. IV. Diagnosis by radioallergosorbent test (R.A.S.T.)

International Nuclear Information System (INIS)

Sobotka, A.K.; Adkinson, N.F. Jr.; Valentine, M.D.; Lichtenstein, L.M.

1978-01-01

Radioallergosorbent tests (RAST(s)) have been developed and assessed for the diagnosis of insect hypersensitivity by using a purified allergen from honeybee venom, phospholipase A, and crude yellow jacket venom. Sera from 193 patients positive both by history and skin test to one of these insects were compared with various groups of control sera. Eighty percent of sera from skin test-positive patients were RAST positive; positive RAST were found in 16% of sera tested from skin test-negative patients. A highly positive RAST correlates well with a positive skin test and clinical sensitivity, but serum IgE is not measurable in many patients with mast cell or basophil bound antibody. Since biologically important reactions of antigen with IgE require that the antibody be cell bound, skin testing would be preferred to RAST if one were limited to a single test for the diagnosis of insect allergy

Active control of magneto-hydrodynamic instabilities in hot plasmas

CERN Document Server

2015-01-01

During the past century, world-wide energy consumption has risen dramatically, which leads to a quest for new energy sources. Fusion of hydrogen atoms in hot plasmas is an attractive approach to solve the energy problem, with abundant fuel, inherent safety and no long-lived radioactivity.  However, one of the limits on plasma performance is due to the various classes of magneto-hydrodynamic instabilities that may occur. The physics and control of these instabilities in modern magnetic confinement fusion devices is the subject of this book. Written by foremost experts, the contributions will provide valuable reference and up-to-date research reviews for "old hands" and newcomers alike.

Effect of cold plasma on the Kelvin-Helmholtz instability

International Nuclear Information System (INIS)

Melander, B.G.

1978-01-01

The thesis studies the effect of a two-component plasma (hot and cold) on the shear driven Kelvin-Helmholtz instability. An ion distribution with a shear flow parallel to the ambient magnetic field and a density gradient parallel to the shear direction is used. Both the electrostatic and electromagnetic versions of the instability are studied in the limit of hydromagnetic frequencies. The dispersion relation is obtained in the electrostatic case by solving the Vlasov equation for the perturbed ion and electron densities and then using the quasineutrality condition. In the electromagnetic case the coupled Vlasov and Maxwell's equations are solved to obtain the dispersion relation

Histochemical and molecular evaluation of the prevalence of Leishmania spp. in hematophagous insects

Directory of Open Access Journals (Sweden)

Willian Marinho Dourado Coelho

2016-06-01

Full Text Available The prevalence study of Leishmania spp. in hematophagous insects captured from the environment in bat roosts and pigeon nests, or feeding their hosts (cattle, pigs, horses, dogs and humans in urban, peri-urban and rural areas, between 2012 and 2014. For this study, the amastigotes present in these insects were detected by histochemical and PCR techniques. Positive gene amplification for Leishmania was found in two horseflies of the species Tabanus importunus collected in the environment, and amastigote forms of Leishmania spp., as well as erythrocytes and leukocytes, were histochemically detected in one of that insect. The other analyzed insects were not positive by PCR our by direct parasitological examination. Only horseflies captured in urban and peri-urban areas were positive. During the collection, no phlebotomine sand flies were captured in rural areas far from the city limits. It can be concluded that the discovery of horseflies positive for Leishmania spp. in urban and peri-urban areas indicates the likelihood that urban areas and their surroundings provide vector parasites with an environment suitable for the spread and consequent perpetuation of the biological cycle of this protozoan.

Insect-induced effects on plants and possible effectors used by galling and leaf-mining insects to manipulate their host-plant.

Science.gov (United States)

Giron, David; Huguet, Elisabeth; Stone, Graham N; Body, Mélanie

2016-01-01

Gall-inducing insects are iconic examples in the manipulation and reprogramming of plant development, inducing spectacular morphological and physiological changes of host-plant tissues within which the insect feeds and grows. Despite decades of research, effectors involved in gall induction and basic mechanisms of gall formation remain unknown. Recent research suggests that some aspects of the plant manipulation shown by gall-inducers may be shared with other insect herbivorous life histories. Here, we illustrate similarities and contrasts by reviewing current knowledge of metabolic and morphological effects induced on plants by gall-inducing and leaf-mining insects, and ask whether leaf-miners can also be considered to be plant reprogrammers. We review key plant functions targeted by various plant reprogrammers, including plant-manipulating insects and nematodes, and functionally characterize insect herbivore-derived effectors to provide a broader understanding of possible mechanisms used in host-plant manipulation. Consequences of plant reprogramming in terms of ecology, coevolution and diversification of plant-manipulating insects are also discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

PSR experience with beam losses, instabilities and space charge effects

International Nuclear Information System (INIS)

Macek, R.J.

1998-01-01

Average current from the PSR has been limited to ∼70 μA at 20 Hz by beam losses of 0.4 to 0.5 μA which arise from two principal causes, production of H 0 excited states and stored-beam scattering in the stripper foil. To reduce beam losses, an upgrade from the two-step H 0 injection to direct H - injection is underway and will be completed in 1998. Peak intensity from the PSR is limited by a strong instability that available evidence indicates is the two-stream e-p instability. New evidence for the e-p hypothesis is presented. At operating intensities, the incoherent space charge tune shift depresses both horizontal and vertical tunes past the integer without additional beam loss although some intensity-dependent emittance growth is observed. copyright 1998 American Institute of Physics

Genetic basis of the sterile insect technique

International Nuclear Information System (INIS)

Robinson, A.S.

2014-01-01

The use of the sterile insect technique for insect control relies on the introduction of sterility in the females of the wild population. This sterility is produced following the mating of these females with released males carrying, in their sperm, dominant lethal mutations that have been induced by ionizing radiation. As well as radiation-induced sterility, natural mechanisms can be recruited, especially the use of hybrid sterility. Radiation is usually one of the last procedures that insects undergo before leaving mass-rearing facilities for release in the field. It is essential that the dosimetry of the radiation source be checked to ensure that all the insects receive the required minimum dose. A dose should be chosen that maximizes the level of introduced sterility in the wild females in the field. Irradiation in nitrogen can provide protection against the detrimental somatic effects of radiation. Currently, the development of molecular methods to sterilize pest insects in the field, by the release of fertile insects carrying trans genes, is very much in vogue. It is concluded that using a physical process, such as radiation, will always have significant advantages over genetic and other methods of sterilization for the large-scale application of the sterile insect technique. (author)

Insect herbivores associated with Baccharis dracunculifolia (Asteraceae: responses of gall-forming and free-feeding insects to latitudinal variation

Directory of Open Access Journals (Sweden)

Marcílio Fagundes

2011-09-01

Full Text Available The spatial heterogeneity hypothesis has been invoked to explain the increase in species diversity from the poles to the tropics: the tropics may be more diverse because they contain more habitats and microhabitats. In this paper, the spatial heterogeneity hypothesis prediction was tested by evaluating the variation in richness of two guilds of insect herbivores (gall-formers and free-feeders associated with Baccharis dracunculifolia (Asteraceae along a latitudinal variation in Brazil. The seventeen populations of B. dracunculifolia selected for insect herbivores sampling were within structurally similar habitats, along the N-S distributional limit of the host plant, near the Brazilian sea coast. Thirty shrubs were surveyed in each host plant population. A total of 8 201 galls and 864 free-feeding insect herbivores belonging to 28 families and 88 species were sampled. The majority of the insects found on B. dracunculifolia were restricted to a specific site rather than having ageographic distribution mirroring that of the host plant. Species richness of free-feeding insects was not affected by latitudinal variation corroborating the spatial heterogeneity hypothesis. Species richness of gall-forming insects was positively correlated with latitude, probably because galling insect associated with Baccharris genus radiated in Southern Brazil. Other diversity indices and evenness estimated for both gall-forming and free feeding insect herbivores, did not change with latitude, suggesting a general structure for different assemblages of herbivores associated with the host plant B. dracunculifolia. Thus it is probable that, insect fauna sample in each site resulted of large scale events, as speciation, migration and coevolution, while at local level, the population of these insects is regulated by ecological forces which operate in the system. Rev. Biol. Trop. 59 (3: 1419-1432. Epub 2011 September 01.La hipótesis de heterogeneidad espacial se ha

Longitudinal beam instabilities in a double RF system

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00229208; Gazis, Evangelos

Operation with a double RF system is essential for many accelerators in order to increase beam stability, to change the bunch shape or to perform various RF manipulations. This is also the case for the operation of the CERN SPS as the LHC proton injector, where in addition to the main RF system, a fourth harmonic RF system is used in bunch shortening mode in order to increase the synchrotron frequency spread inside the bunch and thus to enhance Landau damping of the collective instabilities. In fact the double RF system operation in the SPS is one of the essential means, together with the controlled longitudinal emittance blow-up to significantly increase the longitudinal instability thresholds (single and multi-bunch) and deliver a good quality beam for the LHC. However, for the HiLumi-LHC (HL-LHC) and LHC injector upgrade (LIU) projects higher beam intensities are required. After all upgrades are in place, the main performance limitations of the LHC injector complex are beam instabilities and high intensity...

Insect Immunity: The Post-Genomic Era

OpenAIRE

Bangham, Jenny; Jiggins, Frank; Lemaitre, Bruno

2006-01-01

Insects have a complex and effective immune system, many components of which are conserved in mammals. But only in the last decade have the molecular mechanisms that regulate the insect immune response--and their relevance to general biology and human immunology--become fully appreciated. A meeting supported by the Centre National de la Récherche Scientifique (France) was held to bring together the whole spectrum of researchers working on insect immunity. The meeting addressed diverse aspects...

Fungi with multifunctional lifestyles: endophytic insect pathogenic fungi.

Science.gov (United States)

Barelli, Larissa; Moonjely, Soumya; Behie, Scott W; Bidochka, Michael J

2016-04-01

This review examines the symbiotic, evolutionary, proteomic and genetic basis for a group of fungi that occupy a specialized niche as insect pathogens as well as endophytes. We focus primarily on species in the genera Metarhizium and Beauveria, traditionally recognized as insect pathogenic fungi but are also found as plant symbionts. Phylogenetic evidence suggests that these fungi are more closely related to grass endophytes and diverged from that lineage ca. 100 MYA. We explore how the dual life cycles of these fungi as insect pathogens and endophytes are coupled. We discuss the evolution of insect pathogenesis while maintaining an endophytic lifestyle and provide examples of genes that may be involved in the transition toward insect pathogenicity. That is, some genes for insect pathogenesis may have been co-opted from genes involved in endophytic colonization. Other genes may be multifunctional and serve in both lifestyle capacities. We suggest that their evolution as insect pathogens allowed them to effectively barter a specialized nitrogen source (i.e. insects) with host plants for photosynthate. These ubiquitous fungi may play an important role as plant growth promoters and have a potential reservoir of secondary metabolites.

Horizontal Transmission of Intracellular Insect Symbionts via Plants

Directory of Open Access Journals (Sweden)

Ewa Chrostek

2017-11-01

Full Text Available Experimental evidence is accumulating that endosymbionts of phytophagous insects may transmit horizontally via plants. Intracellular symbionts known for manipulating insect reproduction and altering fitness (Rickettsia, Cardinium, Wolbachia, and bacterial parasite of the leafhopper Euscelidius variegatus have been found to travel from infected insects into plants. Other insects, either of the same or different species can acquire the symbiont from the plant through feeding, and in some cases transfer it to their progeny. These reports prompt many questions regarding how intracellular insect symbionts are delivered to plants and how they affect them. Are symbionts passively transported along the insect-plant-insect path, or do they actively participate in the process? How widespread are these interactions? How does symbiont presence influence the plant? And what conditions are required for the new infection to establish in an insect? From an ecological, evolutionary, and applied perspective, this mode of horizontal transmission could have profound implications if occurring frequently enough or if new stable symbiont infections are established. Transmission of symbionts through plants likely represents an underappreciated means of infection, both in terms of symbiont epidemiology and the movement of symbionts to new host species.

Electron/electron acoustic instability

International Nuclear Information System (INIS)

Gary, S.P.

1987-01-01

The electron acoustic wave becomes a normal mode of an unmagnetized collisionless plasma in the presence of two electron components with similar densities, but strongly disparate temperatures. The characteristic frequency of this mode is the plasma frequency of the cooler electron component. If these two electron components have a relative drift speed several times the thermal speed of the cooler component, the electron/electron acoustic instability may arise. This paper describes the parametric dependences of the threshold drift speed and maximum growth rate of this instability, and compares these with the same properties of the electron/ion acoustic instability. Under the condition of zero current, the electron/ion acoustic instability typically has the lower threshold drift speed, so that observation of the electron/electron acoustic instability is a strong indication of the presence of an electrical current in the plasma

Recombinant DNA technology and insect control

International Nuclear Information System (INIS)

Seawright, J.A.; Cockburn, Andrew F.

1989-01-01

In the past, the most successful avenue for the use of genetics in insect control has been the employment of the sterile insect technique, in which huge numbers of a species are produced in a factory, sterilized by exposure to ionizing radiation and released into the native habitat. this method is suitable for some species, but for logistical, economical, and biological reasons this control technique is not suitable for many economically important species. Our ability to use genetic approaches to cope with the myriad of insect pests will improve in the near future because of progress in the biochemical manipulation of genes. Molecular geneticists have created bacteria, plants, animals, and fungi that have useful new properties, and many of these are being used or tested for commercial use. A reasonable forecast is that a virtual revolution will occur in the way that we currently practice and perceive the genetic control of insects. Using genetic engineering manipulations to develop control techniques for insects of agricultural and public health importance is an exciting prospect and a highly desirable goal

Recombinant DNA technology and insect control

Energy Technology Data Exchange (ETDEWEB)

Seawright, J A; Cockburn, Andrew F [Insects Affecting Man and Animals Laboratory, Agric. Res. Serv., U.S. Department of Agriculture, Gainesville, FL (United States)

1989-08-01

In the past, the most successful avenue for the use of genetics in insect control has been the employment of the sterile insect technique, in which huge numbers of a species are produced in a factory, sterilized by exposure to ionizing radiation and released into the native habitat. this method is suitable for some species, but for logistical, economical, and biological reasons this control technique is not suitable for many economically important species. Our ability to use genetic approaches to cope with the myriad of insect pests will improve in the near future because of progress in the biochemical manipulation of genes. Molecular geneticists have created bacteria, plants, animals, and fungi that have useful new properties, and many of these are being used or tested for commercial use. A reasonable forecast is that a virtual revolution will occur in the way that we currently practice and perceive the genetic control of insects. Using genetic engineering manipulations to develop control techniques for insects of agricultural and public health importance is an exciting prospect and a highly desirable goal.

The equatorial E-region and its plasma instabilities: a tutorial

Directory of Open Access Journals (Sweden)

D. T. Farley

2009-04-01

Full Text Available In this short tutorial we first briefly review the basic physics of the E-region of the equatorial ionosphere, with emphasis on the strong electrojet current system that drives plasma instabilities and generates strong plasma waves that are easily detected by radars and rocket probes. We then discuss the instabilities themselves, both the theory and some examples of the observational data. These instabilities have now been studied for about half a century (!, beginning with the IGY, particularly at the Jicamarca Radio Observatory in Peru. The linear fluid theory of the important processes is now well understood, but there are still questions about some kinetic effects, not to mention the considerable amount of work to be done before we have a full quantitative understanding of the limiting nonlinear processes that determine the details of what we actually observe. As our observational techniques, especially the radar techniques, improve, we find some answers, but also more and more questions. One difficulty with studying natural phenomena, such as these instabilities, is that we cannot perform active cause-and-effect experiments; we are limited to the inputs and responses that nature provides. The one hope here is the steadily growing capability of numerical plasma simulations. If we can accurately simulate the relevant plasma physics, we can control the inputs and measure the responses in great detail. Unfortunately, the problem is inherently three-dimensional, and we still need somewhat more computer power than is currently available, although we have come a long way.

Insect immunology and hematopoiesis

OpenAIRE

Hillyer, Julián F.

2015-01-01

Insects combat infection by mounting powerful immune responses that are mediated by hemocytes, the fat body, the midgut, the salivary glands and other tissues. Foreign organisms that have entered the body of an insect are recognized by the immune system when pathogen-associated molecular patterns bind host-derived pattern recognition receptors. This, in turn, activates immune signaling pathways that amplify the immune response, induce the production of factors with antimicrobial activity, and...

Conditions for l =1 Pomeranchuk instability in a Fermi liquid

Science.gov (United States)

Wu, Yi-Ming; Klein, Avraham; Chubukov, Andrey V.

2018-04-01

We perform a microscopic analysis of how the constraints imposed by conservation laws affect q =0 Pomeranchuk instabilities in a Fermi liquid. The conventional view is that these instabilities are determined by the static interaction between low-energy quasiparticles near the Fermi surface, in the limit of vanishing momentum transfer q . The condition for a Pomeranchuk instability is set by Flc (s )=-1 , where Flc (s ) (a Landau parameter) is a properly normalized partial component of the antisymmetrized static interaction F (k ,k +q ;p ,p -q ) in a charge (c) or spin (s) subchannel with angular momentum l . However, it is known that conservation laws for total spin and charge prevent Pomeranchuk instabilities for l =1 spin- and charge-current order parameters. Our study aims to understand whether this holds only for these special forms of l =1 order parameters or is a more generic result. To this end we perform a diagrammatic analysis of spin and charge susceptibilities for charge and spin density order parameters, as well as perturbative calculations to second order in the Hubbard U . We argue that for l =1 spin-current and charge-current order parameters, certain vertex functions, which are determined by high-energy fermions, vanish at Fl=1 c (s )=-1 , preventing a Pomeranchuk instability from taking place. For an order parameter with a generic l =1 form factor, the vertex function is not expressed in terms of Fl=1 c (s ), and a Pomeranchuk instability may occur when F1c (s )=-1 . We argue that for other values of l , a Pomeranchuk instability may occur at Flc (s )=-1 for an order parameter with any form factor.

Diverse honeydew-consuming fungal communities associated with scale insects.

Directory of Open Access Journals (Sweden)

Manpreet K Dhami

Full Text Available Sooty mould fungi are ubiquitous, abundant consumers of insect-honeydew that have been little-studied. They form a complex of unrelated fungi that coexist and compete for honeydew, which is a chemically complex resource. In this study, we used scanning electron microscopy in combination with T-RFLP community profiling and ITS-based tag-pyrosequencing to extensively describe the sooty mould community associated with the honeydews of two ecologically important New Zealand coelostomidiid scale insects, Coelostomidia wairoensis and Ultracoelostoma brittini. We tested the influence of host plant on the community composition of associated sooty moulds, and undertook limited analyses to examine the influence of scale insect species and geographic location. We report here a previously unknown degree of fungal diversity present in this complex, with pyrosequencing detecting on average 243 operational taxonomic units across the different sooty mould samples. In contrast, T-RFLP detected only a total of 24 different "species" (unique peaks. Nevertheless, both techniques identified similar patterns of diversity suggesting that either method is appropriate for community profiling. The composition of the microbial community associated with individual scale insect species varied although the differences may in part reflect variation in host preference and site. Scanning electron microscopy visualised an intertwined mass of fungal hyphae and fruiting bodies in near-intact physical condition, but was unable to distinguish between the different fungal communities on a morphological level, highlighting the need for molecular research. The substantial diversity revealed for the first time by pyrosequencing and our inability to identify two-thirds of the diversity to further than the fungal division highlights the significant gap in our knowledge of these fungal groups. This study provides a first extensive look at the community diversity of the fungal community

Combustion instability modeling and analysis

Energy Technology Data Exchange (ETDEWEB)

Santoro, R.J.; Yang, V.; Santavicca, D.A. [Pennsylvania State Univ., University Park, PA (United States)] [and others

1995-10-01

It is well known that the two key elements for achieving low emissions and high performance in a gas turbine combustor are to simultaneously establish (1) a lean combustion zone for maintaining low NO{sub x} emissions and (2) rapid mixing for good ignition and flame stability. However, these requirements, when coupled with the short combustor lengths used to limit the residence time for NO formation typical of advanced gas turbine combustors, can lead to problems regarding unburned hydrocarbons (UHC) and carbon monoxide (CO) emissions, as well as the occurrence of combustion instabilities. Clearly, the key to successful gas turbine development is based on understanding the effects of geometry and operating conditions on combustion instability, emissions (including UHC, CO and NO{sub x}) and performance. The concurrent development of suitable analytical and numerical models that are validated with experimental studies is important for achieving this objective. A major benefit of the present research will be to provide for the first time an experimentally verified model of emissions and performance of gas turbine combustors.

Instabilities in strongly coupled plasmas

CERN Document Server

Kalman, G J

2003-01-01

The conventional Vlasov treatment of beam-plasma instabilities is inappropriate when the plasma is strongly coupled. In the strongly coupled liquid state, the strong correlations between the dust grains fundamentally affect the conditions for instability. In the crystalline state, the inherent anisotropy couples the longitudinal and transverse polarizations, and results in unstable excitations in both polarizations. We summarize analyses of resonant and non-resonant, as well as resistive instabilities. We consider both ion-dust streaming and dust beam-plasma instabilities. Strong coupling, in general, leads to an enhancement of the growth rates. In the crystalline phase, a resonant transverse instability can be excited.

Electronic nose in edible insects area

OpenAIRE

Martin Adámek; Anna Adámková; Marie Borkovcová; Jiří Mlček; Martina Bednářová; Lenka Kouřimská; Josef Skácel; Michal Řezníček

2017-01-01

Edible insect is appraised by many cultures as delicious and nutritionally beneficial food. In western countries this commodity is not fully appreciated, and the worries about edible insect food safety prevail. Electronic noses can become a simple and cheap way of securing the health safety of food, and they can also become a tool for evaluating the quality of certain commodities. This research is a pilot project of using an electronic nose in edible insect culinary treatment, and this manusc...

Feeding Studies of Irradiated Foods with Insects

Energy Technology Data Exchange (ETDEWEB)

Loaharanu, Srisan

1978-06-15

Insects are of value to man in many scientific studies. Microsomal detoxication systems exist in both insects and mammals. In the preliminary investigations it was found that irradiated cocoa beans and white and red kidney beans (Phaseolus spp.) did not significantly change the percentage of egg-hatch in the insects tested. In more detailed investigations food samples that are susceptible to insect spoilage and are representatives of widely consumed human foods were fed to various insect species. The development, sex distortion and reproductivity of the insects were investigated. Cytogenetic aberrations as related to dominant lethality were studied in insects with reasonably clear chromosomal patterns. The meiosis stage was examined, using the squash technique and Aceto-orcein staining. Black beans, Phaseolus spp., irradiated with up to 200 krad of gamma rays did not apparently change the percentage of survival and the sex ratio of the bean weevil, Zabrotes subfasciatus. Dominant lethality in the German cockroach, Blatella germanica, fed on irradiated black beans did not apparently occur when considering the results of cytological investigation and the number of offspring obtained. Dried sardine samples irradiated with up to 400 krad of gamma rays neither apparently affected the survival nor caused sex distortion in the cheese skipper, Piophila casei. This irradiated product apparently did not induce dominant lethality in the German cockroach as tested. Coffee processed from coffee beans that had been irradiated with up to 100 krad of gamma rays did not apparently cause adverse effects on the experimental insects. (author)

Feeding studies of irradiated foods with insects

International Nuclear Information System (INIS)

Loaharanu, S.

1978-01-01

Insects are of value to man in many scientific studies. Microsomal detoxication systems exist in both insects and mammals. In the preliminary investigations it was found that irradiated cocoa beans and white and red kidney beans (Phaseolus spp.) did not significantly change the percentage of egg-hatch in the insects tested. In more detailed investigations food samples that are susceptible to insect spoilage and are representatives of widely consumed human foods were fed to various insect species. The development, sex distortion and reproductivity of the insects were investigated. Cytogenetic aberrations as related to dominant lethality were studied in insects with reasonably clear chromosomal patterns. The meiosis stage was examined, using the squash technique and Aceto-orcein staining. Black beans, Phaseolus spp., irradiated with up to 200 krad of gamma rays did not apparently change the percentage of survival and the sex ratio of the bean weevil, Zabrotes subfasciatus. Dominant lethality in the German cockroach, Blatella germanica, fed on irradiated black beans did not apparently occur when considering the results of cytological investigation and the number of offspring obtained. Dried sardine samples irradiated with up to 400 krad of gamma rays neither apparently affected the survival nor caused sex distortion in the cheese skipper, Piophila casei. This irradiated product apparently did not induce dominant lethality in the German cockroach as tested. Coffee processed from coffee beans that had been irradiated with up to 100 krad of gamma rays did not apparently cause adverse effects on the experimental insects. (author)

Effects of fluid instabilities on laser fusion pellets

International Nuclear Information System (INIS)

Mead, W.C.; Lindl, J.D.

1975-01-01

A direct two-dimensional simulation method for fluid flow and plasma physics was used. The computer code LASNEX models the plasma phenomena of laser light absorption by inverse bremsstrahlung and plasma instabilities; energy transport and partition, using flux-limited diffusion and separate ion, electron, and radiation temperatures; and, optionally, effects of multigroup photon and particle transport and magnetic field physics. The fluid dynamics itself is Lagrangian, with an equation of state used to determine pressure, energy, and opacity as a function of density and temperature. Thermonuclear burn of compressed matter is included to permit evaluation of output to input energy ratios. The code tests with anomalies are described. Current understanding of fluid instability in the presence of ablation is discussed. (U.S.)

Ubiquity of insect-derived nitrogen transfer to plants by endophytic insect-pathogenic fungi: an additional branch of the soil nitrogen cycle.

Science.gov (United States)

Behie, Scott W; Bidochka, Michael J

2014-03-01

The study of symbiotic nitrogen transfer in soil has largely focused on nitrogen-fixing bacteria. Vascular plants can lose a substantial amount of their nitrogen through insect herbivory. Previously, we showed that plants were able to reacquire nitrogen from insects through a partnership with the endophytic, insect-pathogenic fungus Metarhizium robertsii. That is, the endophytic capability and insect pathogenicity of M. robertsii are coupled so that the fungus acts as a conduit to provide insect-derived nitrogen to plant hosts. Here, we assess the ubiquity of this nitrogen transfer in five Metarhizium species representing those with broad (M. robertsii, M. brunneum, and M. guizhouense) and narrower insect host ranges (M. acridum and M. flavoviride), as well as the insect-pathogenic fungi Beauveria bassiana and Lecanicillium lecanii. Insects were injected with (15)N-labeled nitrogen, and we tracked the incorporation of (15)N into two dicots, haricot bean (Phaseolus vulgaris) and soybean (Glycine max), and two monocots, switchgrass (Panicum virgatum) and wheat (Triticum aestivum), in the presence of these fungi in soil microcosms. All Metarhizium species and B. bassiana but not L. lecanii showed the capacity to transfer nitrogen to plants, although to various degrees. Endophytic association by these fungi increased overall plant productivity. We also showed that in the field, where microbial competition is potentially high, M. robertsii was able to transfer insect-derived nitrogen to plants. Metarhizium spp. and B. bassiana have a worldwide distribution with high soil abundance and may play an important role in the ecological cycling of insect nitrogen back to plant communities.

Genomic instability and radiation

Energy Technology Data Exchange (ETDEWEB)

Little, John B [Harvard School of Public Health, Boston, MA 02115 (United States)

2003-06-01

Genomic instability is a hallmark of cancer cells, and is thought to be involved in the process of carcinogenesis. Indeed, a number of rare genetic disorders associated with a predisposition to cancer are characterised by genomic instability occurring in somatic cells. Of particular interest is the observation that transmissible instability can be induced in somatic cells from normal individuals by exposure to ionising radiation, leading to a persistent enhancement in the rate at which mutations and chromosomal aberrations arise in the progeny of the irradiated cells after many generations of replication. If such induced instability is involved in radiation carcinogenesis, it would imply that the initial carcinogenic event may not be a rare mutation occurring in a specific gene or set of genes. Rather, radiation may induce a process of instability in many cells in a population, enhancing the rate at which the multiple gene mutations necessary for the development of cancer may arise in a given cell lineage. Furthermore, radiation could act at any stage in the development of cancer by facilitating the accumulation of the remaining genetic events required to produce a fully malignant tumour. The experimental evidence for such induced instability is reviewed. (review)

Genomic instability and radiation

International Nuclear Information System (INIS)

Little, John B

2003-01-01

Genomic instability is a hallmark of cancer cells, and is thought to be involved in the process of carcinogenesis. Indeed, a number of rare genetic disorders associated with a predisposition to cancer are characterised by genomic instability occurring in somatic cells. Of particular interest is the observation that transmissible instability can be induced in somatic cells from normal individuals by exposure to ionising radiation, leading to a persistent enhancement in the rate at which mutations and chromosomal aberrations arise in the progeny of the irradiated cells after many generations of replication. If such induced instability is involved in radiation carcinogenesis, it would imply that the initial carcinogenic event may not be a rare mutation occurring in a specific gene or set of genes. Rather, radiation may induce a process of instability in many cells in a population, enhancing the rate at which the multiple gene mutations necessary for the development of cancer may arise in a given cell lineage. Furthermore, radiation could act at any stage in the development of cancer by facilitating the accumulation of the remaining genetic events required to produce a fully malignant tumour. The experimental evidence for such induced instability is reviewed. (review)

Anatomy of adult Megaphragma (Hymenoptera: Trichogrammatidae, one of the smallest insects, and new insight into insect miniaturization.

Directory of Open Access Journals (Sweden)

Alexey A Polilov

Full Text Available The body size, especially in cases of extreme reduction, is an important characteristic that strongly determines the morphology, physiology, and biology of animals. Miniaturization is a widespread trend in animal evolution and one of the principal directions of evolution in insects. Miniaturization-related features of insect morphology have been subject to intensive studies during the last few years, but the structure of the smallest insects remains insufficiently known. It is especially important to study hymenopterans of the genus Megaphragma, which include the smallest flying insects and a species in which an almost anucleate nervous system was recently discovered. This article is the first detailed study of the external and internal morphology of adults of Megaphragma mymaripenne and M. amalphitanum using histological methods, 3D computer modeling and other techniques. It is shown that in spite of the extremely small size the organization of Megaphragma retains a considerkable level of structural complexity. On the other hand, miniaturization leads to re-organizations of several organ systems. Unique structural features related to miniaturization have been found in both species: lysis of cell bodies and nuclei of neurons at late stages of pupal development, absence of the heart, and considerable reductions in the set of muscles. Comparative analysis of structure in the smallest insects representing different taxa has revealed common features of the evolutionary process of miniaturization in insects.

Stripes instability of an oscillating non-Brownian iso-dense suspension of spheres

Science.gov (United States)

Roht, Y. L.; Ippolito, I.; Hulin, J. P.; Salin, D.; Gauthier, G.

2018-03-01

We analyze experimentally the behavior of a non-Brownian, iso-dense suspension of spheres submitted to periodic square wave oscillations of the flow in a Hele-Shaw cell of gap H. We do observe an instability of the initially homogeneous concentration in the form of concentration variation stripes transverse to the flow. The wavelength of these regular spatial structures scales roughly as the gap of the cell and is independent of the particle concentration and of the period of oscillation. This instability requires large enough particle volume fractions φ≥ 0.25 and a gap large enough compared to the sphere diameter (H/d ≥ 8) . Mapping the domain of the existence of this instability in the space of the control parameters shows that it occurs only in a limited range of amplitudes of the fluid displacement. The analysis of the concentration distribution across the gap supports a scenario of particle migration towards the wall followed by an instability due to a particle concentration gradient with a larger concentration at the walls. In order to account for the main features of this stripes instability, we use the theory of longitudinal instability due to normal stresses difference and recent observations of a dependence of the first normal stresses difference on the particle concentration.

Ionizing radiation perception by insects

International Nuclear Information System (INIS)

Campanhola, C.

1980-04-01

The proof of the existence of a perception for ionizing radiation by insects was aimed at, as well as the determination of its processing mechanism. It was tried also to check if such perception induces the insects to keep away from the radiation source, proving therefore a protection against the harms caused by ionizing radiation, or else the stimulus for such behaviour is similar to that caused by light radiations. 60 Co and 241 Am were used as gamma radiation sources, the 60 Co source of 0.435mCi and the 241 Am of 99.68mCi activity. Adult insects were used with the following treatments : exposure to 60 Co and 241 Am radiation and non-exposure (control). A total of approximately 50 insects per replication was released in the central region of an opaque white wooden barrier divided into 3 sections with the same area - 60.0 cm diameter and 7.5 cm height - covered with a nylon screen. 5 replications per treatment were made and the distribution of the insects was evaluated by photographs taken at 15, 30, 45, and 60 minutes after release. Sitophilus oryzae (l., 1763) and Ephestia cautella (Walker, 1864) showed some response to 241 Am gamma radiation, i.e. negative tactism. It was concluded that ionizing radiations can be detected by insects through direct visual stimulus or by visual stimulus reslting from interaction of radiation-Cerenkov radiation - with some other occular component with a refraction index greater than water. Also, the activity of the radioactive source with regard to perception for ionizing radiation, is of relevance in comparison with the energy of the radiation emitted by same, or in other words, what really matters is the radiation dose absorbed. (Author) [pt

Current limitation in low pressure mercury arcs

International Nuclear Information System (INIS)

Torven, S.; Babic, M.

1976-06-01

When the electric current in a low pressure arc with a long positive column is increased sufficiently, an electrostatic instability develops in the plasma which leads to formation of thin space charge layers across the column. The instability is investigated in a mercury plasma column kept axially homogeneous by a special technique. Values of some plasma parameters are measured at the instability threshold. It is found that the plasma is in a weakly ionized state in contrast to predictions by widely accepted current limitation theories. It is concluded that new types of theories are required to explain the observations. (Auth.)

Solar wind heat flux regulation by the whistler instability

International Nuclear Information System (INIS)

Gary, S.P.; Feldman, W.C.

1977-01-01

This paper studies the role of the whistler instability in the regulation of the solar wind heat flux near 1 AU. A comparison of linear and second-order theory with experimental results provides strong evidence that the whistler may at times contribute to the limitation of this heat flux

Instability and dynamics of volatile thin films

Science.gov (United States)

Ji, Hangjie; Witelski, Thomas P.

2018-02-01

Volatile viscous fluids on partially wetting solid substrates can exhibit interesting interfacial instabilities and pattern formation. We study the dynamics of vapor condensation and fluid evaporation governed by a one-sided model in a low-Reynolds-number lubrication approximation incorporating surface tension, intermolecular effects, and evaporative fluxes. Parameter ranges for evaporation-dominated and condensation-dominated regimes and a critical case are identified. Interfacial instabilities driven by the competition between the disjoining pressure and evaporative effects are studied via linear stability analysis. Transient pattern formation in nearly flat evolving films in the critical case is investigated. In the weak evaporation limit unstable modes of finite-amplitude nonuniform steady states lead to rich droplet dynamics, including flattening, symmetry breaking, and droplet merging. Numerical simulations show that long-time behaviors leading to evaporation or condensation are sensitive to transitions between filmwise and dropwise dynamics.

Made for Each Other: Ascomycete Yeasts and Insects.

Science.gov (United States)

Blackwell, Meredith

2017-06-01

Fungi and insects live together in the same habitats, and many species of both groups rely on each other for success. Insects, the most successful animals on Earth, cannot produce sterols, essential vitamins, and many enzymes; fungi, often yeast-like in growth form, make up for these deficits. Fungi, however, require constantly replenished substrates because they consume the previous ones, and insects, sometimes lured by volatile fungal compounds, carry fungi directly to a similar, but fresh, habitat. Yeasts associated with insects include Ascomycota (Saccharomycotina, Pezizomycotina) and a few Basidiomycota. Beetles, homopterans, and flies are important associates of fungi, and in turn the insects carry yeasts in pits, specialized external pouches, and modified gut pockets. Some yeasts undergo sexual reproduction within the insect gut, where the genetic diversity of the population is increased, while others, well suited to their stable environment, may never mate. The range of interactions extends from dispersal of yeasts on the surface of insects (e.g., cactus- Drosophila -yeast and ephemeral flower communities, ambrosia beetles, yeasts with holdfasts) to extremely specialized associations of organisms that can no longer exist independently, as in the case of yeast-like symbionts of planthoppers. In a few cases yeast-like fungus-insect associations threaten butterflies and other species with extinction. Technical advances improve discovery and identification of the fungi but also inform our understanding of the evolution of yeast-insect symbioses, although there is much more to learn.

Modes of storage ring coherent instabilities

Energy Technology Data Exchange (ETDEWEB)

Wang, J.M.

1986-12-01

Longitudinal impedance in a beam and various modes of longitudinal coherent instabilities are discussed. The coasting beam coherent instability, microwave instability, and single-bunch longitudinal coherent instabilities are considered. The Vlasov equation is formulated, and a method of solving it is developed. The synchrotron modes are treated, which take the possible bunch shape distortion fully into consideration. A method of treating the synchrotron mode coupling in the case of a small bunch is discussed which takes advantage of the fact that only a few of the synchrotron modes can contribute in such a case. The effect of many bunches on the coherent motion of the beam and the longitudinal symmetric coupled bunch modes are discussed. The transverse impedance is then introduced, and the transverse coasting beam instability is discussed. Various bunched beam instabilities are discussed, including both single bunch instabilities and coupled bunch instabilities. The Vlasov equation for transverse as well as longitudinal motion of particles is introduced as well as a method of solving it within a linear approximation. Head-tail modes and short bunch instabilities and strong coupling instabilities in the long bunch case are covered. (LEW)

Modes of storage ring coherent instabilities

International Nuclear Information System (INIS)

Wang, J.M.

1986-12-01

Longitudinal impedance in a beam and various modes of longitudinal coherent instabilities are discussed. The coasting beam coherent instability, microwave instability, and single-bunch longitudinal coherent instabilities are considered. The Vlasov equation is formulated, and a method of solving it is developed. The synchrotron modes are treated, which take the possible bunch shape distortion fully into consideration. A method of treating the synchrotron mode coupling in the case of a small bunch is discussed which takes advantage of the fact that only a few of the synchrotron modes can contribute in such a case. The effect of many bunches on the coherent motion of the beam and the longitudinal symmetric coupled bunch modes are discussed. The transverse impedance is then introduced, and the transverse coasting beam instability is discussed. Various bunched beam instabilities are discussed, including both single bunch instabilities and coupled bunch instabilities. The Vlasov equation for transverse as well as longitudinal motion of particles is introduced as well as a method of solving it within a linear approximation. Head-tail modes and short bunch instabilities and strong coupling instabilities in the long bunch case are covered

Phenotypic Plasticity of Cuticular Hydrocarbon Profiles in Insects.

Science.gov (United States)

Otte, Tobias; Hilker, Monika; Geiselhardt, Sven

2018-03-01

The insect integument is covered by cuticular hydrocarbons (CHCs) which provide protection against environmental stresses, but are also used for communication. Here we review current knowledge on environmental and insect-internal factors which shape phenotypic plasticity of solitary living insects, especially herbivorous ones. We address the dynamics of changes which may occur within minutes, but may also last weeks, depending on the species and conditions. Two different modes of changes are suggested, i.e. stepwise and gradual. A switch between two distinct environments (e.g. host plant switch by phytophagous insects) results in stepwise formation of two distinct adaptive phenotypes, while a gradual environmental change (e.g. temperature gradients) induces a gradual change of numerous adaptive CHC phenotypes. We further discuss the ecological and evolutionary consequences of phenotypic plasticity of insect CHC profiles by addressing the question at which conditions is CHC phenotypic plasticity beneficial. The high plasticity of CHC profiles might be a trade-off for insects using CHCs for communication. We discuss how insects cope with the challenge to produce and "understand" a highly plastic, environmentally dependent CHC pattern that conveys reliable and comprehensible information. Finally, we outline how phenotypic plasticity of CHC profiles may promote speciation in insects that rely on CHCs for mate recognition.

RNA Interference in Insect Vectors for Plant Viruses

Directory of Open Access Journals (Sweden)

Surapathrudu Kanakala

2016-12-01

Full Text Available Insects and other arthropods are the most important vectors of plant pathogens. The majority of plant pathogens are disseminated by arthropod vectors such as aphids, beetles, leafhoppers, planthoppers, thrips and whiteflies. Transmission of plant pathogens and the challenges in managing insect vectors due to insecticide resistance are factors that contribute to major food losses in agriculture. RNA interference (RNAi was recently suggested as a promising strategy for controlling insect pests, including those that serve as important vectors for plant pathogens. The last decade has witnessed a dramatic increase in the functional analysis of insect genes, especially those whose silencing results in mortality or interference with pathogen transmission. The identification of such candidates poses a major challenge for increasing the role of RNAi in pest control. Another challenge is to understand the RNAi machinery in insect cells and whether components that were identified in other organisms are also present in insect. This review will focus on summarizing success cases in which RNAi was used for silencing genes in insect vector for plant pathogens, and will be particularly helpful for vector biologists.

Thermal shrinkage for shoulder instability.

Science.gov (United States)

Toth, Alison P; Warren, Russell F; Petrigliano, Frank A; Doward, David A; Cordasco, Frank A; Altchek, David W; O'Brien, Stephen J

2011-07-01

Thermal capsular shrinkage was popular for the treatment of shoulder instability, despite a paucity of outcomes data in the literature defining the indications for this procedure or supporting its long-term efficacy. The purpose of this study was to perform a clinical evaluation of radiofrequency thermal capsular shrinkage for the treatment of shoulder instability, with a minimum 2-year follow-up. From 1999 to 2001, 101 consecutive patients with mild to moderate shoulder instability underwent shoulder stabilization surgery with thermal capsular shrinkage using a monopolar radiofrequency device. Follow-up included a subjective outcome questionnaire, discussion of pain, instability, and activity level. Mean follow-up was 3.3 years (range 2.0-4.7 years). The thermal capsular shrinkage procedure failed due to instability and/or pain in 31% of shoulders at a mean time of 39 months. In patients with unidirectional anterior instability and those with concomitant labral repair, the procedure proved effective. Patients with multidirectional instability had moderate success. In contrast, four of five patients with isolated posterior instability failed. Thermal capsular shrinkage has been advocated for the treatment of shoulder instability, particularly mild to moderate capsular laxity. The ease of the procedure makes it attractive. However, our retrospective review revealed an overall failure rate of 31% in 80 patients with 2-year minimum follow-up. This mid- to long-term cohort study adds to the literature lacking support for thermal capsulorrhaphy in general, particularly posterior instability. The online version of this article (doi:10.1007/s11420-010-9187-7) contains supplementary material, which is available to authorized users.

Strategies for Enhanced Crop Resistance to Insect Pests.

Science.gov (United States)

Douglas, Angela E

2018-04-29

Insect pests are responsible for substantial crop losses worldwide through direct damage and transmission of plant diseases, and novel approaches that complement or replace broad-spectrum chemical insecticides will facilitate the sustainable intensification of food production in the coming decades. Multiple strategies for improved crop resistance to insect pests, especially strategies relating to plant secondary metabolism and immunity and microbiome science, are becoming available. Recent advances in metabolic engineering of plant secondary chemistry offer the promise of specific toxicity or deterrence to insect pests; improved understanding of plant immunity against insects provides routes to optimize plant defenses against insects; and the microbiomes of insect pests can be exploited, either as a target or as a vehicle for delivery of insecticidal agents. Implementation of these advances will be facilitated by ongoing advances in plant breeding and genetic technologies.

Insect Detectives

Indian Academy of Sciences (India)

2002-08-01

Aug 1, 2002 ... He writes popular science articles in ... science, English poetry is his area of ... A fascinating branch of insect science (ento- ... Methods in Forensic Entomology .... bullet wound to the right temple, and a substantial pooling of.

Australian Consumers' Awareness and Acceptance of Insects as Food.

Science.gov (United States)

Wilkinson, Kerry; Muhlhausler, Beverly; Motley, Crystal; Crump, Anna; Bray, Heather; Ankeny, Rachel

2018-04-19

Insects have long been consumed as part of the diets of many Asian, African, and South American cultures. However, despite international agencies such as the Food and Agriculture Organization of the United Nations advocating the nutritional, environmental, and economic benefits of entomophagy, attitudinal barriers persist in Western societies. In Australia, the indigenous ‘bush tucker’ diet comprising witchetty grubs, honey ants, and Bogong moths is quite well known; however, in most Australian locales, the consumption of insects tends to occur only as a novelty. Therefore, this study aimed to investigate the awareness and acceptance of insects as food. An online survey of 820 consumers found that 68% of participants had heard of entomophagy, but only 21% had previously eaten insects; witchetty grubs, ants, grasshoppers, and crickets were the most commonly tasted insects. Taste, appearance, safety, and quality were identified as the factors that were most likely to influence consumer willingness to try eating insects, but consumer attitudes towards entomophagy were underpinned by both food neophobia (i.e., reluctance to eat new or novel foods) and prior consumption of insects. Neophobic consumers were far less accepting of entomophagy than neophilic consumers, while consumers who had previously eaten insects were most accepting of insects as food. Incorporating insects into familiar products (e.g., biscuits) or cooked meals also improved their appeal. Collectively, these findings can be used by the food industry to devise production and/or marketing strategies that overcome barriers to insect consumption in Australia.

Australian Consumers’ Awareness and Acceptance of Insects as Food

Directory of Open Access Journals (Sweden)

Kerry Wilkinson

2018-04-01

Full Text Available Insects have long been consumed as part of the diets of many Asian, African, and South American cultures. However, despite international agencies such as the Food and Agriculture Organization of the United Nations advocating the nutritional, environmental, and economic benefits of entomophagy, attitudinal barriers persist in Western societies. In Australia, the indigenous ‘bush tucker’ diet comprising witchetty grubs, honey ants, and Bogong moths is quite well known; however, in most Australian locales, the consumption of insects tends to occur only as a novelty. Therefore, this study aimed to investigate the awareness and acceptance of insects as food. An online survey of 820 consumers found that 68% of participants had heard of entomophagy, but only 21% had previously eaten insects; witchetty grubs, ants, grasshoppers, and crickets were the most commonly tasted insects. Taste, appearance, safety, and quality were identified as the factors that were most likely to influence consumer willingness to try eating insects, but consumer attitudes towards entomophagy were underpinned by both food neophobia (i.e., reluctance to eat new or novel foods and prior consumption of insects. Neophobic consumers were far less accepting of entomophagy than neophilic consumers, while consumers who had previously eaten insects were most accepting of insects as food. Incorporating insects into familiar products (e.g., biscuits or cooked meals also improved their appeal. Collectively, these findings can be used by the food industry to devise production and/or marketing strategies that overcome barriers to insect consumption in Australia.

Experimental and numerical investigation on two-phase flow instabilities

Energy Technology Data Exchange (ETDEWEB)

Ruspini, Leonardo Carlos

2013-03-01

Two-phase flow instabilities are experimentally and numerically studied within this thesis. In particular, the phenomena called Ledinegg instability, density wave oscillations and pressure drop oscillations are investigated. The most important investigations regarding the occurrence of two-phase flow instabilities are reviewed. An extensive description of the main contributions in the experimental and analytical research is presented. In addition, a critical discussion and recommendations for future investigations are presented. A numerical framework using a hp-adaptive method is developed in order to solve the conservation equations modelling general thermo-hydraulic systems. A natural convection problem is analysed numerically in order to test the numerical solver. Moreover, the description of an adaptive strategy to solve thermo-hydraulic problems is presented. In the second part of this dissertation, a homogeneous model is used to study Ledinegg, density wave and pressure drop oscillations phenomena numerically. The dynamic characteristics of the Ledinegg (flow excursion) phenomenon are analysed through the simulation of several transient examples. In addition, density wave instabilities in boiling and condensing systems are investigated. The effects of several parameters, such as the fluid inertia and compressibility volumes, on the stability limits of Ledinegg and density wave instabilities are studied, showing a strong influence of these parameters. Moreover, the phenomenon called pressure drop oscillations is numerically investigated. A discussion of the physical representation of several models is presented with reference to the obtained numerical results. Finally, the influence of different parameters on these phenomena is analysed. In the last part, an experimental investigation of these phenomena is presented. The designing methodology used for the construction of the experimental facility is described. Several simulations and a non

Shoulder instability in professional football players.

Science.gov (United States)

Leclere, Lance E; Asnis, Peter D; Griffith, Matthew H; Granito, David; Berkson, Eric M; Gill, Thomas J

2013-09-01

Shoulder instability is a common problem in American football players entering the National Football League (NFL). Treatment options include nonoperative and surgical stabilization. This study evaluated how the method of treatment of pre-NFL shoulder instability affects the rate of recurrence and the time elapsed until recurrence in players on 1 NFL team. Retrospective cohort. Medical records from 1980 to 2008 for 1 NFL team were reviewed. There were 328 players included in the study who started their career on the team and remained on the team for at least 2 years (mean, 3.9 years; range, 2-14 years). The history of instability prior to entering the NFL and the method of treatment were collected. Data on the occurrence of instability while in the NFL were recorded to determine the rate and timing of recurrence. Thirty-one players (9.5%) had a history of instability prior to entering the NFL. Of the 297 players with no history of instability, 39 (13.1%) had a primary event at a mean of 18.4 ± 22.2 months (range, 0-102 months) after joining the team. In the group of players with prior instability treated with surgical stabilization, there was no statistical difference in the rate of recurrence (10.5%) or the timing to the instability episode (mean, 26 months) compared with players with no history of instability. Twelve players had shoulder instability treated nonoperatively prior to the NFL. Five of these players (41.7%) had recurrent instability at a mean of 4.4 ± 7.0 months (range, 0-16 months). The patients treated nonoperatively had a significantly higher rate of recurrence (P = 0.02) and an earlier time of recurrence (P = 0.04). The rate of contralateral instability was 25.8%, occurring at a mean of 8.6 months. Recurrent shoulder instability is more common in NFL players with a history of nonoperative treatment. Surgical stabilization appears to restore the rate and timing of instability to that of players with no prior history of instability.

Intercropping System for Protection the Potato Plant from Insect Infestation

Directory of Open Access Journals (Sweden)

Aziza Sharaby

2015-06-01

Full Text Available The use of intercropping system provides an option for insect control for organic farmers that are limited in their chemical use. Additionally, intercropping systems can be attractive to conventional growers as a cost-effective insect control solution. A study was carried out for two seasons 2011-2012 and 2012-2013 to evaluate the effect of intercropping of potato (Solanum tuberosum L. with onion (Allium cepa L. on whitefly (Bemicia tabasi Gennadius and aphids’ Myzus persicae Sulz. and Aphis gossypii Glover infestation in potato fields. Results indicated that intercropping significantly reduced potato plant infestation with whitefly by 42.7, 51.3% while it was 62.69% reduction with aphids during the two successive winter seasons than when potato plants were cultivated alone. Therefore, intercropping could be recommended as a protection method of reducing pest population in the fields.

Endocrinology of insects

National Research Council Canada - National Science Library

Downer, Roger G. H; Laufer, Hans

1983-01-01

Contents: Organization of the neuroendocrine system - Chemistry of insect hormones and neurohormones - Regulation of metamorphosis - Regulation of reproduction - Regulation of growth and development...

Plasma physics and instabilities

International Nuclear Information System (INIS)

Lashmore-Davies, C.N.

1981-01-01

These lectures procide an introduction to the theory of plasmas and their instabilities. Starting from the Bogoliubov, Born, Green, Kirkwood, and Yvon (BBGKY) hierarchy of kinetic equations, the additional concept of self-consistent fields leads to the fundamental Vlasov equation and hence to the warm two-fluid model and the one-fluid MHD, or cold, model. The properties of small-amplitude waves in magnetized (and unmagnetized) plasmas, and the instabilities to which they give rise, are described in some detail, and a complete chapter is devoted to Landau damping. The linear theory of plasma instabilities is illustrated by the current-driven electrostatic kind, with descriptions of the Penrose criterion and the energy principle of ideal MHD. There is a brief account of the application of feedback control. The non-linear theory is represented by three examples: quasi-linear velocity-space instabilities, three-wave instabilities, and the stability of an arbitrarily largeamplitude wave in a plasma. (orig.)

X-ray photoevaporation's limited success in the formation of planetesimals by the streaming instability

Science.gov (United States)

Ercolano, Barbara; Jennings, Jeff; Rosotti, Giovanni; Birnstiel, Tilman

2017-12-01

The streaming instability is often invoked as solution to the fragmentation and drift barriers in planetesimal formation, catalysing the aggregation of dust on kyr time-scales to grow km-sized cores. However, there remains a lack of consensus on the physical mechanism(s) responsible for initiating it. One potential avenue is disc photoevaporation, wherein the preferential removal of relatively dust-free gas increases the disc metallicity. Late in the disc lifetime, photoevaporation dominates viscous accretion, creating a gradient in the depleted gas surface density near the location of the gap. This induces a local pressure maximum that collects drifting dust particles, which may then become susceptible to the streaming instability. Using a one-dimensional viscous evolution model of a disc subject to internal X-ray photoevaporation, we explore the efficacy of this process to build planetesimals. Over a range of parameters, we find that the amount of dust mass converted into planetesimals is often planetary cores. Our results are in contrast to a recent, similar investigation that considered an far-ultra-violet (FUV)-driven photoevaporation model and reported the formation of tens of M⊕ at large (>100 au) disc radii. The discrepancies are primarily a consequence of the different photoevaporation profiles assumed. Until observations more tightly constrain photoevaporation models, the relevance of this process to the formation of planets remains uncertain.

Tomographic reconstruction of neopterous carboniferous insect nymphs.

Directory of Open Access Journals (Sweden)

Russell Garwood

Full Text Available Two new polyneopteran insect nymphs from the Montceau-les-Mines Lagerstätte of France are presented. Both are preserved in three dimensions, and are imaged with the aid of X-ray micro-tomography, allowing their morphology to be recovered in unprecedented detail. One-Anebos phrixos gen. et sp. nov.-is of uncertain affinities, and preserves portions of the antennae and eyes, coupled with a heavily spined habitus. The other is a roachoid with long antennae and chewing mouthparts very similar in form to the most generalized mandibulate mouthparts of extant orthopteroid insects. Computer reconstructions reveal limbs in both specimens, allowing identification of the segments and annulation in the tarsus, while poorly developed thoracic wing pads suggest both are young instars. This work describes the morphologically best-known Palaeozoic insect nymphs, allowing a better understanding of the juveniles' palaeobiology and palaeoecology. We also consider the validity of evidence from Palaeozoic juvenile insects in wing origin theories. The study of juvenile Palaeozoic insects is currently a neglected field, yet these fossils provide direct evidence on the evolution of insect development. It is hoped this study will stimulate a renewed interest in such work.

Learning in Insect Pollinators and Herbivores.

Science.gov (United States)

Jones, Patricia L; Agrawal, Anurag A

2017-01-31

The relationship between plants and insects is influenced by insects' behavioral decisions during foraging and oviposition. In mutualistic pollinators and antagonistic herbivores, past experience (learning) affects such decisions, which ultimately can impact plant fitness. The higher levels of dietary generalism in pollinators than in herbivores may be an explanation for the differences in learning seen between these two groups. Generalist pollinators experience a high level of environmental variation, which we suggest favors associative learning. Larval herbivores employ habituation and sensitization-strategies useful in their less variable environments. Exceptions to these patterns based on habitats, mobility, and life history provide critical tests of current theory. Relevant plant traits should be under selection to be easily learned and remembered in pollinators and difficult to learn in herbivores. Insect learning thereby has the potential to have an important, yet largely unexplored, role in plant-insect coevolution.

Radiobiology of Small Hive Beetle (Coleoptera: Nitidulidae) and Prospects for Management Using Sterile Insect

International Nuclear Information System (INIS)

Downey, Danielle; Chun, Stacey; Follett, Peter

2016-01-01

Small hive beetle, Aethina tumida Murray (Coleoptera: Nitidulidae), is considered a serious threat to beekeeping in the Western Hemisphere, Australia, and Europe mainly due to larval feeding on honey, pollen, and brood of the European honeybee, Apis mellifera L. Control methods are limited for this pest. Studies were conducted to provide information on the radiobiology of small hive beetle and determine the potential for sterile insect releases as a control strategy. Adult males and females were equally sensitive to a radiation dose of 80 Gy and died within 5–7 d after treatment. In reciprocal crossing studies, irradiation of females only lowered reproduction to a greater extent than irradiation of males only. For matings between unirradiated males and irradiated females, mean reproduction was reduced by >99% at 45 and 60 Gy compared with controls, and no larvae were produced at 75 Gy. Irradiation of prereproductive adults of both sexes at 45 Gy under low oxygen (1–4%) caused a high level of sterility (>99%) while maintaining moderate survivorship for several weeks, and should suffice for sterile insect releases. Sterile insect technique holds potential for suppressing small hive beetle populations in newly invaded areas and limiting its spread. (author)

Allergic risks of consuming edible insects: A systematic review.

Science.gov (United States)

Ribeiro, José Carlos; Cunha, Luís Miguel; Sousa-Pinto, Bernardo; Fonseca, João

2018-01-01

The expected future demand for food and animal-derived protein will require environment-friendly novel food sources with high nutritional value. Insects may be one of such novel food sources. However, there needs to be an assessment of the risks associated with their consumption, including allergic risks. Therefore, we performed a systematic review aiming to analyse current data available regarding the allergic risks of consuming insects. We reviewed all reported cases of food allergy to insects, and studied the possibility of cross-reactivity and co-sensitisation between edible insects, crustaceans and house dust mites. We analysed a total of 25 articles - eight assessing the cross-reactivity/co-sensitisation between edible insects, crustaceans and house dust mites; three characterizing allergens in edible insects and 14 case reports, describing case series or prevalence studies of food allergy caused by insects. Cross-reactivity/co-sensitisation between edible insects and crustaceans seems to be clinically relevant, while it is still unknown if co-sensitisation between house dust mites and edible insects can lead to a food allergy. Additionally, more information is also needed about the molecular mechanisms underlying food allergy to insects, although current data suggest that an important role is played by arthropod pan-allergens such as tropomyosin or arginine kinase. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Three-way interaction among plants, bacteria, and coleopteran insects.

Science.gov (United States)

Wielkopolan, Beata; Obrępalska-Stęplowska, Aleksandra

2016-08-01

Coleoptera, the largest and the most diverse Insecta order, is characterized by multiple adaptations to plant feeding. Insect-associated microorganisms can be important mediators and modulators of interactions between insects and plants. Interactions between plants and insects are highly complex and involve multiple factors. There are various defense mechanisms initiated by plants upon attack by herbivorous insects, including the development of morphological structures and the synthesis of toxic secondary metabolites and volatiles. In turn, herbivores have adapted to feeding on plants and further sophisticated adaptations to overcome plant responses may continue to evolve. Herbivorous insects may detoxify toxic phytocompounds, sequester poisonous plant factors, and alter their own overall gene expression pattern. Moreover, insects are associated with microbes, which not only considerably affect insects, but can also modify plant defense responses to the benefit of their host. Plants are also frequently associated with endophytes, which may act as bioinsecticides. Therefore, it is very important to consider the factors influencing the interaction between plants and insects. Herbivorous insects cause considerable damage to global crop production. Coleoptera is the largest and the most diverse order in the class Insecta. In this review, various aspects of the interactions among insects, microbes, and plants are described with a focus on coleopteran species, their bacterial symbionts, and their plant hosts to demonstrate that many factors contribute to the success of coleopteran herbivory.

Insect anaphylaxis: where are we? The stinging facts 2012.

Science.gov (United States)

Tracy, James M; Khan, Fatima S; Demain, Jeffrey G

2012-08-01

Insect allergy remains an important cause of morbidity and mortality in the United States. In 2011, the third iteration of the stinging insect hypersensitivity practice parameter was published, the first being published in 1999 and the second in 2004. Since the 2004 edition, our understanding of insect hypersensitivity has continued to expand and has been incorporated into the 2011 edition. This work will review the relevant changes in the management of insect hypersensitivity occurring since 2004 and present our current understanding of the insect hypersensitivity diagnosis and management. Since the 2004 commissioning by the Joint Task Force (JTF) on Practice Parameters of 'Stinging insect hypersensitivity: a practice parameter update', there have been important contributions to our understanding of insect allergy. These contributions were incorporated into the 2011 iteration. Similar efforts were made by the European Allergy Asthma and Clinical Immunology Interest Group in 2005 and most recently in 2011 by the British Society of Allergy and Clinical Immunology. Our understanding of insect allergy, including the natural history, epidemiology, diagnostic testing, and risk factors, has greatly expanded. This evolution of knowledge should provide improved long-term management of stinging insect hypersensitivity. This review will focus primarily on the changes between the 2004 and 2011 stinging insect practice parameter commissioned by the JTF on Practice Parameters, but will, where appropriate, highlight the differences between working groups.

Gravitational Instabilities in Circumstellar Disks

Science.gov (United States)

Kratter, Kaitlin; Lodato, Giuseppe

2016-09-01

Star and planet formation are the complex outcomes of gravitational collapse and angular momentum transport mediated by protostellar and protoplanetary disks. In this review, we focus on the role of gravitational instability in this process. We begin with a brief overview of the observational evidence for massive disks that might be subject to gravitational instability and then highlight the diverse ways in which the instability manifests itself in protostellar and protoplanetary disks: the generation of spiral arms, small-scale turbulence-like density fluctuations, and fragmentation of the disk itself. We present the analytic theory that describes the linear growth phase of the instability supplemented with a survey of numerical simulations that aim to capture the nonlinear evolution. We emphasize the role of thermodynamics and large-scale infall in controlling the outcome of the instability. Despite apparent controversies in the literature, we show a remarkable level of agreement between analytic predictions and numerical results. In the next part of our review, we focus on the astrophysical consequences of the instability. We show that the disks most likely to be gravitationally unstable are young and relatively massive compared with their host star, Md/M*≥0.1. They will develop quasi-stable spiral arms that process infall from the background cloud. Although instability is less likely at later times, once infall becomes less important, the manifestations of the instability are more varied. In this regime, the disk thermodynamics, often regulated by stellar irradiation, dictates the development and evolution of the instability. In some cases the instability may lead to fragmentation into bound companions. These companions are more likely to be brown dwarfs or stars than planetary mass objects. Finally, we highlight open questions related to the development of a turbulent cascade in thin disks and the role of mode-mode coupling in setting the maximum angular

The simultaneous onset and interaction of Taylor and Dean instabilities in a Couette geometry

International Nuclear Information System (INIS)

Hills, C P; Bassom, A P

2005-01-01

The fluid flow between a pair of coaxial circular cylinders generated by the uniform rotation of the inner cylinder and an azimuthal pressure gradient is susceptible to both Taylor and Dean type instabilities. The flow can be characterised by two parameters: a measure of the relative magnitude of the rotation and pressure effects and a non-dimensional Taylor number. Neutral curves associated with each instability can be constructed but it has been suggested that these curves do not cross but rather posses 'kinks'. Our work is based in the small gap, large wavenumber limit and considers the simultaneous onset of Taylor and Dean instabilities. The two linear instabilities interact at exponentially small orders and a consistent, matched asymptotic solution is found across the whole annular domain, identifying five regions of interest: two boundary adjustment regions and three internal critical points. We construct necessary conditions for the concurrent onset of the linear Taylor and Dean instabilities and show that neutral curve crossing is possible

Fungal endophytes which invade insect galls: insect pathogens, benign saprophytes, or fungal inquilines?

Science.gov (United States)

Wilson, Dennis

1995-08-01

Fungi are frequently found within insect galls. However, the origin of these fungi, whether they are acting as pathogens, saprophytes invading already dead galls, or fungal inquilines which invade the gall but kill the gall maker by indirect means, is rarely investigated. A pathogenic role for these fungi is usually inferred but never tested. I chose the following leaf-galling-insect/host-plant pairs (1) a cynipid which forms two-chambered galls on the veins of Oregon white oak, (2) a cynipid which forms single-chambered galls on California coast live oak, and (3) an aphid which forms galls on narrowleaf cottonwood leaves. All pairs were reported to have fungi associated with dead insects inside the gall. These fungi were cultured and identified. For the two cynipids, all fungi found inside the galls were also present in the leaves as fungal endophytes. The cottonwood leaves examined did not harbor fungal endophytes. For the cynipid on Oregon white oak, the fungal endophyte grows from the leaf into the gall and infects all gall tissue but does not directly kill the gall maker. The insect dies as a result of the gall tissue dying from fungal infection. Therefore, the fungus acts as an inquiline. Approximately 12.5% of these galls die as a result of invasion by the fungal endophyte.

Spatial distribution of aquatic insects

DEFF Research Database (Denmark)

Iversen, Lars Lønsmann

(time since glacial disturbance and habitat stability) and question the generality of these processes for the understanding of species richness gradients in European rivers. Using regional distributions of European mayflies, stoneflies, and caddisflies this chapter demonstrates that differences...... and shape the habitat requirements and distribution of one of the most affected groups of freshwater species: aquatic insects. It comprises four chapters each addressing different spatial factors in relation to the occurrence of aquatic insects in Europe. Chapter I examine two spatial ecological processes...... niche is derived from local distribution patterns, without incorporating landscape history it can lead to an erroneous niche definition. Chapter III provides some of the first evidence for differences in dispersal phenology related to flight potential in aquatic insects. The chapter highlights...

Instability characteristics of fluidelastic instability of tube rows in crossflow

International Nuclear Information System (INIS)

Chen, S.S.; Jendrzejczyk, J.A.

1986-04-01

An experimental study is reported to investigate the jump phenomenon in critical flow velocities for tube rows with different pitch-to-diameter ratios and the excited and intrinsic instabilities for a tube row with a pitch-to-diameter ratio of 1.75. The experimental data provide additional insights into the instability phenomena of tube arrays in crossflow. 9 refs., 10 figs

Nonlinear Longitudinal Mode Instability in Liquid Propellant Rocket Engine Preburners

Science.gov (United States)

Sims, J. D. (Technical Monitor); Flandro, Gary A.; Majdalani, Joseph; Sims, Joseph D.

2004-01-01

Nonlinear pressure oscillations have been observed in liquid propellant rocket instability preburner devices. Unlike the familiar transverse mode instabilities that characterize primary combustion chambers, these oscillations appear as longitudinal gas motions with frequencies that are typical of the chamber axial acoustic modes. In several respects, the phenomenon is similar to longitudinal mode combustion instability appearing in low-smoke solid propellant motors. An important feature is evidence of steep-fronted wave motions with very high amplitude. Clearly, gas motions of this type threaten the mechanical integrity of associated engine components and create unacceptably high vibration levels. This paper focuses on development of the analytical tools needed to predict, diagnose, and correct instabilities of this type. For this purpose, mechanisms that lead to steep-fronted, high-amplitude pressure waves are described in detail. It is shown that such gas motions are the outcome of the natural steepening process in which initially low amplitude standing acoustic waves grow into shock-like disturbances. The energy source that promotes this behavior is a combination of unsteady combustion energy release and interactions with the quasi-steady mean chamber flow. Since shock waves characterize the gas motions, detonation-like mechanisms may well control the unsteady combustion processes. When the energy gains exceed the losses (represented mainly by nozzle and viscous damping), the waves can rapidly grow to a finite amplitude limit cycle. Analytical tools are described that allow the prediction of the limit cycle amplitude and show the dependence of this wave amplitude on the system geometry and other design parameters. This information can be used to guide corrective procedures that mitigate or eliminate the oscillations.

Effects of mass transfer on a resonance instability in the laminar ...

Indian Academy of Sciences (India)

pressible boundary layer flow due to a rotating-disk is investigated in this paper based on the linear stability theory. The possible .... Reynolds number limit to the inviscid modes strongly suggests that the resonance instability identified here ...

Molecular identification of the insect adipokinetic hormone receptors

DEFF Research Database (Denmark)

Staubli, Frank; Jørgensen, Thomas J D; Cazzamali, Giuseppe

2002-01-01

identified the first insect AKH receptors, namely those from the fruitfly Drosophila melanogaster and the silkworm Bombyx mori. These results represent a breakthrough for insect molecular endocrinology, because it will lead to the cloning of all AKH receptors from all model insects used in AKH research, and...

Coconut leaf bioactivity toward generalist maize insect pests

Science.gov (United States)

Tropical plants are often more resistant to insects than temperate plants due to evolution of robust defenses to cope with a more constant insect threat. Coconut (Cocos nucifera L.) has very few chewing leaf feeding insect pests and was tested against two omnivorous leaf feeding caterpillar species,...

Response of native insect communities to invasive plants.

Science.gov (United States)

Bezemer, T Martijn; Harvey, Jeffrey A; Cronin, James T

2014-01-01

Invasive plants can disrupt a range of trophic interactions in native communities. As a novel resource they can affect the performance of native insect herbivores and their natural enemies such as parasitoids and predators, and this can lead to host shifts of these herbivores and natural enemies. Through the release of volatile compounds, and by changing the chemical complexity of the habitat, invasive plants can also affect the behavior of native insects such as herbivores, parasitoids, and pollinators. Studies that compare insects on related native and invasive plants in invaded habitats show that the abundance of insect herbivores is often lower on invasive plants, but that damage levels are similar. The impact of invasive plants on the population dynamics of resident insect species has been rarely examined, but invasive plants can influence the spatial and temporal dynamics of native insect (meta)populations and communities, ultimately leading to changes at the landscape level.

Localized instabilities and spinodal decomposition in driven systems in the presence of elasticity

Science.gov (United States)

Meca, Esteban; Münch, Andreas; Wagner, Barbara

2018-01-01

We study numerically and analytically the instabilities associated with phase separation in a solid layer on which an external material flux is imposed. The first instability is localized within a boundary layer at the exposed free surface by a process akin to spinodal decomposition. In the limiting static case, when there is no material flux, the coherent spinodal decomposition is recovered. In the present problem, stability analysis of the time-dependent and nonuniform base states as well as numerical simulations of the full governing equations are used to establish the dependence of the wavelength and onset of the instability on parameter settings and its transient nature as the patterns eventually coarsen into a flat moving front. The second instability is related to the Mullins-Sekerka instability in the presence of elasticity and arises at the moving front between the two phases when the flux is reversed. Stability analyses of the full model and the corresponding sharp-interface model are carried out and compared. Our results demonstrate how interface and bulk instabilities can be analyzed within the same framework which allows us to identify and distinguish each of them clearly. The relevance for a detailed understanding of both instabilities and their interconnections in a realistic setting is demonstrated for a system of equations modeling the lithiation and delithiation processes within the context of lithium ion batteries.

Self-field instabilities in high-$J_{c}$ Nb$_{3}$Sn strands the effect of copper RRR

CERN Document Server

Bordini, B

2009-01-01

High critical current density (Jc) Nb$_{3}$Sn conductor is the best candidate for next generation high field (> 10 T) accelerator magnets. Although very promising, state of the art high-Jc Nb$_{3}$Sn strands suffer of magneto-thermal instabilities that can severely limit the strand performance. Recently it has been shown that at 1.9 K the self field instability is the dominating mechanism that limits the performance of strands with a low (<10) Residual Resistivity Ratio (RRR) of the stabilizing copper. At CERN several state of the art high–Jc Nb$_{3}$Sn wires have been tested at 4.2 K and 1.9 K to study the effects on strand self-field instability of: RRR and strand impregnation with stycast. To study the effect of the RRR value on magneto-thermal instabilities, a new 2-D finite element model was also developed at CERN. This model simulates the whole development of the flux jump in the strand cross section also taking into account the heat and current diffusion in the stabilizing copper. In this paper th...

The evolutionary development of plant-feeding insects and their nutritional endosymbionts.

Science.gov (United States)

Skidmore, Isabel H; Hansen, Allison K

2017-12-01

Herbivorous insects have evolved diverse mechanisms enabling them to feed on plants with suboptimal nutrient availability. Low nutrient availability negatively impacts insect herbivore development and fitness. To overcome this obstacle numerous insect lineages have evolved intimate associations with nutritional endosymbionts. This is especially true for insects that specialize on nitrogen-poor substrates, as these insects are highly dependent on intracellular symbionts to provide nitrogen lacking in their insect host's diet. Emerging evidence in these systems suggest that the symbiont's and/or the insect's biosynthetic pathways are dynamically regulated throughout the insect's development to potentially cope with the insect's changing nutritional demands. In this review, we evaluate the evolutionary development of symbiotic insect cells (bacteriocytes) by comparing and contrasting genes and mechanisms involved in maintaining and regulating the nutritional symbiosis throughout insect development in a diversity of insect herbivore-endosymbiont associations. With new advances in genome sequencing and functional genomics, we evaluate to what extent nutritional symbioses are shaped by (i) the regulation of symbiont titer, (ii) the regulation of insect symbiosis genes, and (iii) the regulation of symbiont genes. We discuss how important these mechanisms are for the biosynthesis of essential amino acids and vitamins across insect life stages in divergent insect-symbiont systems. We conclude by suggesting future directions of research to further elucidate the evolutionary development of bacteriocytes and the impact of these nutritional symbioses on insect-plant interactions. © 2017 Institute of Zoology, Chinese Academy of Sciences.

Measurements of a Fast Vertical Instability in the PEP-II HER

International Nuclear Information System (INIS)

Matter, Regina S.

2000-01-01

The HER beam current was limited to tens of mA by a strong vertical coupled bunch instability during PEP-II commissioning in July '98. In the absence of transverse feedback, vertical oscillations were seen to be unstable at currents as low as 5 mA. The instability has been observed by using the HER longitudinal feedback electronics to digitize and store the vertical beam signal used for transverse feedback. This note presents measurements of modal growth and damping rates at two different vacuum pressures for 291 bunch uniform fills as well as 100 and 150 bunch train measurements. In some cases the unstable modes maintain a constant residual amplitude when feedback is on, and exhibit nonlinear behavior when feedback is switched off. Knowledge of the shape, speed and spectral location of the modal transients should help in diagnosing the cause of instability

Research on combustion instability and application to solid propellant rocket motors. II.

Science.gov (United States)

Culick, F. E. C.

1972-01-01

Review of the current state of analyses of combustion instability in solid-propellant rocket motors, citing appropriate measurements and observations. The work discussed has become increasingly important, both for the interpretation of laboratory data and for predicting the transient behavior of disturbances in full-scale motors. Two central questions are considered - namely, linear stability and nonlinear behavior. Several classes of problems are discussed as special cases of a general approach to the analysis of combustion instability. Application to motors, and particularly the limitations presently understood, are stressed.

Field Validation of the Stability Limit of a Multi MW Turbine

Science.gov (United States)

Kallesøe, Bjarne S.; Kragh, Knud A.

2016-09-01

Long slender blades of modern multi-megawatt turbines exhibit a flutter like instability at rotor speeds above a critical rotor speed. Knowing the critical rotor speed is crucial to a safe turbine design. The flutter like instability can only be estimated using geometrically non-linear aeroelastic codes. In this study, the estimated rotor speed stability limit of a 7 MW state of the art wind turbine is validated experimentally. The stability limit is estimated using Siemens Wind Powers in-house aeroelastic code, and the results show that the predicted stability limit is within 5% of the experimentally observed limit.

Helical instability in film blowing process: Analogy to buckling instability

Science.gov (United States)

Lee, Joo Sung; Kwon, Ilyoung; Jung, Hyun Wook; Hyun, Jae Chun

2017-12-01

The film blowing process is one of the most important polymer processing operations, widely used for producing bi-axially oriented film products in a single-step process. Among the instabilities observed in this film blowing process, i.e., draw resonance and helical motion occurring on the inflated film bubble, the helical instability is a unique phenomenon portraying the snake-like undulation motion of the bubble, having the period on the order of few seconds. This helical instability in the film blowing process is commonly found at the process conditions of a high blow-up ratio with too low a freezeline position and/or too high extrusion temperature. In this study, employing an analogy to the buckling instability for falling viscous threads, the compressive force caused by the pressure difference between inside and outside of the film bubble is introduced into the simulation model along with the scaling law derived from the force balance between viscous force and centripetal force of the film bubble. The simulation using this model reveals a close agreement with the experimental results of the film blowing process of polyethylene polymers such as low density polyethylene and linear low density polyethylene.

Functional Instability of the Ankle Joint: Etiopathogenesis

Directory of Open Access Journals (Sweden)

Aydan ÖRSÇELİK

2016-09-01

Full Text Available Ankle sprain is one of the most common sports injuries. Chronic ankle instability is a common complication of ankle sprains. Two causes of chronic ankle instability are mechanical instability and functional instability. It is important to understand functional instability etiopathogenesis of the ankle joint in order to guide diagnosis and treatment. This article aims to understand the etiopathogenesis of functional ankle instability.

POWER STABILITY MONITORING BASED ON VOLTAGE INSTABILITY PREDICTION APPROACH THROUGH WIDE AREA SYSTEM

OpenAIRE

H. H. Goh; Q. S. Chua; S. W. Lee; B. C. Kok; K. C. Goh; K. T.K. Teo

2014-01-01

Nowadays, power systems are being forced to operate closer to its security limit due to current economic growth and the difficulties to upgrade the existing grid infrastructure. With the sudden increment of power demand, voltage instability problem has become a main concern to the power system operator because voltage instability has led or crucially contributed to some major blackouts throughout the world. Hence, methods for early warning and early prevention are required to prevent the powe...

The variable effects of soil nitrogen availability and insect herbivory on aboveground and belowground plant biomass in an old-field ecosystem

DEFF Research Database (Denmark)

Blue, Jarrod D.; Souza, Lara; Classen, Aimée T.

2011-01-01

in an old-field ecosystem. In 2004, we established 36 experimental plots in which we manipulated soil nitrogen (N) availability and insect abundance in a completely randomized plot design. In 2009, after 6 years of treatments, we measured aboveground biomass and assessed root production at peak growth...... not be limiting primary production in this ecosystem. Insects reduced the aboveground biomass of subdominant plant species and decreased coarse root production. We found no statistical interactions between N availability and insect herbivory for any response variable. Overall, the results of 6 years of nutrient...

Viruses of insects reared for food and feed

NARCIS (Netherlands)

Maciel-Vergara, Gabriela; Ros, Vera I.D.

2017-01-01

The use of insects as food for humans or as feed for animals is an alternative for the increasing high demand for meat and has various environmental and social advantages over the traditional intensive production of livestock. Mass rearing of insects, under insect farming conditions or even in

Laser plasma instability experiments with KrF lasers

International Nuclear Information System (INIS)

Weaver, J. L.; Karasik, M.; Serlin, V.; Obenschain, S.; Chan, L-Y.; Kehne, D.; Schmitt, A. J.; Colombant, D.; Velikovich, A.; Oh, J.; Lehmberg, R. H.; Afeyan, B.; Phillips, L.; Seely, J.; Brown, C.; Feldman, U.; Aglitskiy, Y.; Mostovych, A. N.; Holland, G.

2007-01-01

Deleterious effects of laser-plasma instability (LPI) may limit the maximum laser irradiation that can be used for inertial confinement fusion. The short wavelength (248 nm), large bandwidth, and very uniform illumination available with krypton-fluoride (KrF) lasers should increase the maximum usable intensity by suppressing LPI. The concomitant increase in ablation pressure would allow implosion of low-aspect-ratio pellets to ignition with substantial gain (>20) at much reduced laser energy. The proposed KrF-laser-based Fusion Test Facility (FTF) would exploit this strategy to achieve significant fusion power (150 MW) with a rep-rate system that has a per pulse laser energy well below 1 MJ. Measurements of LPI using the Nike KrF laser are presented at and above intensities needed for the FTF (I∼2x10 15 W/cm 2 ). The results to date indicate that LPI is indeed suppressed. With overlapped beam intensity above the planar, single beam intensity threshold for the two-plasmon decay instability, no evidence of instability was observed via measurements of (3/2)ω o and (1/2)ω o harmonic emissions

Nutritional and sensory quality of edible insects

Directory of Open Access Journals (Sweden)

Lenka Kouřimská

2016-10-01

Full Text Available Insects are for many nations and ethnic groups an indispensable part of the diet. From a nutritional point of view, insects have significant protein content. It varies from 20 to 76% of dry matter depending on the type and development stage of the insect. Fat content variability is large (2–50% of dry matter and depends on many factors. Total polyunsaturated fatty acids' content may be up to 70% of total fatty acids. Carbohydrates are represented mainly by chitin, whose content ranges between 2.7 mg and 49.8 mg per kg of fresh matter. Some species of edible insects contain a reasonable amount of minerals (K, Na, Ca, Cu, Fe, Zn, Mn and P as well as vitamins such as B group vitamins, vitamins A, D, E, K, and C. However their content is seasonal and dependent on the feed. From the hygienic point of view it should be pointed out that some insects may produce or contain toxic bioactive compounds. They may also contain residues of pesticides and heavy metals from the ecosystem. Adverse human allergic reactions to edible insects could be also a possible hazard. Keywords: Chitin, Entomophagy, Fat, Minerals, Proteins, Vitamins

Viruses of insects reared for food and feed.

Science.gov (United States)

Maciel-Vergara, Gabriela; Ros, Vera I D

2017-07-01

The use of insects as food for humans or as feed for animals is an alternative for the increasing high demand for meat and has various environmental and social advantages over the traditional intensive production of livestock. Mass rearing of insects, under insect farming conditions or even in industrial settings, can be the key for a change in the way natural resources are utilized in order to produce meat, animal protein and a list of other valuable animal products. However, because insect mass rearing technology is relatively new, little is known about the different factors that determine the quality and yield of the production process. Obtaining such knowledge is crucial for the success of insect-based product development. One of the issues that is likely to compromise the success of insect rearing is the outbreak of insect diseases. In particular, viral diseases can be devastating for the productivity and the quality of mass rearing systems. Prevention and management of viral diseases imply the understanding of the different factors that interact in insect mass rearing. This publication provides an overview of the known viruses in insects most commonly reared for food and feed. Nowadays with large-scale sequencing techniques, new viruses are rapidly being discovered. We discuss factors affecting the emergence of viruses in mass rearing systems, along with virus transmission routes. Finally we provide an overview of the wide range of measures available to prevent and manage virus outbreaks in mass rearing systems, ranging from simple sanitation methods to highly sophisticated methods including RNAi and transgenics. Copyright © 2017 Elsevier Inc. All rights reserved.

Edible insects contributing to food security?

NARCIS (Netherlands)

Huis, van Arnold

2015-01-01

Because of growing demand for meat and declining availability of agricultural land, there is an urgent need to find alternative protein sources. Edible insects can be produced with less environmental impact than livestock. Insect meal can replace scarce fishmeal as feed ingredient, in particular

Edible Insects in Sustainable Food Systems

DEFF Research Database (Denmark)

Halloran, Afton; Flore, Roberto; Vantomme, Paul

This text provides an important overview of the contributions of edible insects to ecological sustainability, livelihoods, nutrition and health, food culture and food systems around the world. While insect farming for both food and feed is rapidly increasing in popularity around the world, the ro...

Insect cadaver applications: pros and cons

Science.gov (United States)

Application of entomopathogenic nematodes (EPNs) formulated as insect cadavers has become an alternative to aqueous application for the control of agricultural pests. In this approach, the infected insect host cadaver is applied directly to the target site and pest suppression is achieved by the inf...

RF and microwave dielectric properties of stored-grain insects and their implications for potential insect control

International Nuclear Information System (INIS)

Nelson, S.O.; Bartley, P.G. Jr.; Lawrence, K.C.

1998-01-01

The permittivities of bulk samples of adult insects of the rice weevil, red flour beetle, sawtoothed grain beetle, and lesser grain borer were measured at single frequencies of 9.4 and 11.7 Ghz in X-band waveguide at about 23 degrees C, and permittivities of homogenized samples of the same species were measured from 0.2 to 20 GHz at temperatures from 10 to 70 degrees C with an open-ended coaxial-line probe and network analyzer. Sample densities for the coaxial-line probe measurements were determined from the X-band measurements with a linear relationship between the cube root of the dielectric constant and sample bulk density determined from permittivity measurements on bulk samples of the adult insects in a waveguide sample holder taken with the short-circuited line technique. Since linearity of the cube root of the dielectric constant with bulk density is consistent with the Landau and Lifshitz, Looyenga dielectric mixture equation, this equation was used to calculate estimated dielectric constants and loss factors of the insects from measured permittivities and volume fractions determined from measured bulk density and adult insect density determined by air-comparison pycnometer measurements. Estimated dielectric constants and loss factors of the insects are presented graphically for temperatures from 10 to 70 degrees C, and tabulated data are provided for range information and comparative purposes

Chromosomal instability induced by ionizing radiation

International Nuclear Information System (INIS)

Morgan, W.F.; Marder, B.A.; Day, J.P.

1995-01-01

There is accumulating evidence indicating genomic instability can manifest multiple generations after cellular exposure to DNA damaging agents. For instance, some cells surviving exposure to ionizing radiations show delayed reproductive cell death, delayed mutation and / or delayed chromosomal instability. Such instability, especially chromosome destabilization has been implicated in mutation, gene amplification, cellular transformation, and cell killing. To investigate chromosomal instability following DNA damage, we have used fluorescence in situ hybridization to detect chromosomal rearrangements in a human/hamster somatic hybrid cell line following exposure to ionizing radiation. Delayed chromosomal instability was detected when multiple populations of uniquely arranged metaphases were observed in clonal isolates raised from single cells. The relationship between delayed chromosomal destabilization and other endpoints of genomic instability, namely; delayed mutation and gene amplification will be discussed, as will the potential cytogenetic and molecular mechanisms contributing to delayed chromosomal instability

Anaphylaxis and insect allergy.

Science.gov (United States)

Demain, Jeffrey G; Minaei, Ashley A; Tracy, James M

2010-08-01

Anaphylaxis is an acute-onset and potentially life-threatening allergic reaction that can be caused by numerous allergic triggers including stinging insects. This review focuses on recent advances, natural history, risk factors and therapeutic considerations. Recent work suggests that concerns over insect allergy diagnosis continue to exist. This is especially true with individuals who have a convincing history of a serious life-threatening anaphylactic event, but lack the necessary diagnostic criteria of venom-specific IgE by skin test or in-vitro diagnostic methods to confirm the diagnosis. The role of occult mastocytosis or increased basophile reactivity may play a role in this subset population. Additionally, epinephrine continues to be underutilized as the primary acute intervention for an anaphylactic reaction in the emergent setting. The incidence of anaphylaxis continues to rise across all demographic groups, especially those less than 20 years of age. Fortunately, the fatalities related to anaphylaxis appear to have decreased over the past decades. Our understanding of various triggers, associated risk factors, as well as an improved understanding and utilization of biological markers such as serum tryptase have improved. Our ability to treat insect anaphylaxis by venom immunotherapy is highly effective. Unfortunately, anaphylaxis continues to be underappreciated and undertreated especially in regard to insect sting anaphylaxis. This includes the appropriate use of injectable epinephrine as the primary acute management tool. These findings suggest that continued education of the general population, primary care healthcare providers and emergency departments is required.

Critical heat flux concerns during the flow instability phase of a DEGB LOCA

International Nuclear Information System (INIS)

Shadday, M.A. Jr.

1990-08-01

Arguments are presented that support the proposal that a separate burnout risk analysis, for the Flow Instability (FI) phase of a LOCA, not be required for reactor restart. With expected reactor power limits, flow instability will occur before critical heat flux (CHF). Since FI power limits preclude the occurrence of flow instability in a bounding accident, a DEGB LOCA, the risk of CHF and attendant burnout is negligible. A review of RDAP data revealed that in the past reactor assemblies operated at flow and power conditions similar to those expected in a LOCA without burnout occurring. This is strong bounding empirical evidence, without the scaling concerns of laboratory experiments. A bounding analysis of the influences of assembly non-idealities on CHF, power tilts, and channel eccentricity, is included. The margin between operating heat fluxes, during the postulated LOCA, and CHF was quantified by scoping calculations. Based on measured azimuthal power variations, the local heat flux would have to be more than 20 standard deviations above the calculated mean heat flux for CHF to occur

Use of necrophagous insects as evidence of cadaver relocation: myth or reality?

Science.gov (United States)

Gosselin, Matthias; Hedouin, Valéry

2017-01-01

The use of insects as indicators of post-mortem displacement is discussed in many texts, courses and TV shows, and several studies addressing this issue have been published. Although the concept is widely cited, it is poorly understood, and only a few forensic cases have successfully applied such a method. The use of necrophagous insects as evidence of cadaver relocation actually involves a wide range of biological aspects. Distribution, microhabitat, phenology, behavioral ecology, and molecular analysis are among the research areas associated with this topic. This article provides the first review of the current knowledge and addresses the potential and limitations of different methods to evaluate their applicability. This work reveals numerous weaknesses and erroneous beliefs as well as many possibilities and research opportunities. PMID:28785513

Use of necrophagous insects as evidence of cadaver relocation: myth or reality?

Directory of Open Access Journals (Sweden)

Damien Charabidze

2017-08-01

Full Text Available The use of insects as indicators of post-mortem displacement is discussed in many texts, courses and TV shows, and several studies addressing this issue have been published. Although the concept is widely cited, it is poorly understood, and only a few forensic cases have successfully applied such a method. The use of necrophagous insects as evidence of cadaver relocation actually involves a wide range of biological aspects. Distribution, microhabitat, phenology, behavioral ecology, and molecular analysis are among the research areas associated with this topic. This article provides the first review of the current knowledge and addresses the potential and limitations of different methods to evaluate their applicability. This work reveals numerous weaknesses and erroneous beliefs as well as many possibilities and research opportunities.

Social insects inspire human design

Science.gov (United States)

Holbrook, C. Tate; Clark, Rebecca M.; Moore, Dani; Overson, Rick P.; Penick, Clint A.; Smith, Adrian A.

2010-01-01

The international conference ‘Social Biomimicry: Insect Societies and Human Design’, hosted by Arizona State University, USA, 18–20 February 2010, explored how the collective behaviour and nest architecture of social insects can inspire innovative and effective solutions to human design challenges. It brought together biologists, designers, engineers, computer scientists, architects and businesspeople, with the dual aims of enriching biology and advancing biomimetic design. PMID:20392721

Fermi-Pasta-Ulam recurrence and modulation instability

Science.gov (United States)

Kuznetsov, E. A.

2017-01-01

We give a qualitative conceptual explanation of the Fermi-Pasta-Ulam (FPU) like recurrence in the onedimensional focusing nonlinear Schrodinger equation (NLSE). The recurrence can be considered as a result of the nonlinear development of the modulation instability. All known exact localized solitary wave solutions describing propagation on the background of the modulationally unstable condensate show the recurrence to the condensate state after its interaction with solitons. The condensate state locally recovers its original form with the same amplitude but a different phase after soliton leave its initial region. Based on the integrability of the NLSE, we demonstrate that the FPU recurrence takes place not only for condensate, but also for a more general solution in the form of the cnoidal wave. This solution is periodic in space and can be represented as a solitonic lattice. That lattice reduces to isolated soliton solution in the limit of large distance between solitons. The lattice transforms into the condensate in the opposite limit of dense soliton packing. The cnoidal wave is also modulationally unstable due to soliton overlapping. The recurrence happens at the nonlinear stage of the modulation instability. Due to generic nature of the underlying mathematical model, the proposed concept can be applied across disciplines and nonlinear systems, ranging from optical communications to hydrodynamics.

Investigation--Insects!

Science.gov (United States)

Fay, Janice

2000-01-01

Presents activities on insects for second grade students. In the first activity, students build a butterfly garden. In the second activity, students observe stimuli reactions with mealworms in the larval stage. Describes the assessment process and discusses the effects of pollution on living things. (YDS)

Impacts of urbanization process on insect diversity

OpenAIRE

Shuisong Ye; Yan Fang; Kai Li

2013-01-01

Rapid worldwide urbanization during the last century has led to more than half the world’s population living in urban regions. Studies of how urbanization affects insect diversity have focused on the following: insect abundance, distribution, extinction, food habits and ecosystem services. Native insect populations have declined greatly in urban areas, where studies of their spatial distribution have revealed that abundance decreases along what is termed the rural–city center gradient (RCG), ...

Bubble velocity in the nonlinear Rayleigh-Taylor instability at a deflagration front

International Nuclear Information System (INIS)

Modestov, Mikhail; Bychkov, Vitaly; Betti, Riccardo; Eriksson, Lars-Erik

2008-01-01

The Rayleigh-Taylor instability at a deflagration front is studied systematically using extensive direct numerical simulations. It is shown that, for a sufficiently large gravitational field, the effects of bubble rising dominate the deflagration dynamics. It is demonstrated both analytically and numerically that the deflagration speed is described asymptotically by the Layzer theory in the limit of large acceleration. In the opposite limit of small and zero gravitational field, intrinsic properties of the deflagration front become important. In that case, the deflagration speed is determined by the velocity of a planar front and by the Darrieus-Landau instability. Because of these effects, the deflagration speed is larger than predicted by the Layzer theory. An analytical formula for the deflagration speed is suggested, which matches two asymptotic limits of large and small acceleration. The formula is in good agreement with the numerical data in a wide range of Froude numbers. The present results are also in agreement with previous numerical simulations on this problem

Toxicological characteristics of edible insects in China: A historical review.

Science.gov (United States)

Gao, Yu; Wang, Di; Xu, Meng-Lei; Shi, Shu-Sen; Xiong, Jin-Feng

2018-04-10

Edible insects are ideal food sources, which contain important nutrients and health-promoting compounds. With a rapid development of industrial insect farming, insect-derived food is a novel and emerging food industry. Edible insects have been traditionally consumed in various communities, while continuously gaining relevance in today's society; however, they currently remain underutilized. Although there are a large number of literature on edible insects, these literature primarily focus on the nutritional value edible insects. The toxicity assessment data of edible insects remain incomprehensive, especially for the new national standard that is currently in effect; and many data and conclusions are not accurately specified/reported. Therefore, we performed a literature review and summarized the data on the toxicological assessment of edible insects in China. The review first describes the research progress on safety toxicological assessment, and then offers references regarding the development of 34 edible insect species in China. These data can be a platform for the development of future toxicological assessment strategies, which can be carried out by a multidisciplinary team, possibly consisting of food engineers, agronomists, farmers, and so on, to improve the acceptability of edible insects. Copyright © 2018 Elsevier Ltd. All rights reserved.

Emerging strategies for RNA interference (RNAi) applications in insects.

Science.gov (United States)

Nandety, Raja Sekhar; Kuo, Yen-Wen; Nouri, Shahideh; Falk, Bryce W

2015-01-01

RNA interference (RNAi) in insects is a gene regulatory process that also plays a vital role in the maintenance and in the regulation of host defenses against invading viruses. Small RNAs determine the specificity of the RNAi through precise recognition of their targets. These small RNAs in insects comprise small interfering RNAs (siRNAs), micro RNAs (miRNAs) and Piwi interacting RNAs (piRNAs) of various lengths. In this review, we have explored different forms of the RNAi inducers that are presently in use, and their applications for an effective and efficient fundamental and practical RNAi research with insects. Further, we reviewed trends in next generation sequencing (NGS) technologies and their importance for insect RNAi, including the identification of novel insect targets as well as insect viruses. Here we also describe a rapidly emerging trend of using plant viruses to deliver the RNAi inducer molecules into insects for an efficient RNAi response.