154 research outputs found

    Influence of prey density, species and developmental stages on the predatory behaviour of Amblyseius longispinosus (Acari: Phytoseiidae)

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    The influence of prey density, species and developmental stages on the predatory behaviour of Amblyseius longispinosus (Evans) was studied. A 24 h exposure revealed that gravid females were more voracious compared to young females. The trends in the number of eggs and larvae consumed by each young and gravid female predator were about the same, showing an increase with density of the red and the yellow strains of T. urticae levelling off at a prey density of 40 per predator. The highest mean number of eggs consumed in 24 h was 16.7 for the young female and 33.3 for the gravid female, and a mean high of 17 larvae in 24 h for the young female and 27.8 for the gravid female. With adult prey, however, the predators reached satiation point at a lower density of five to ten adult prey per female. In general, the response curves were adequately described by the Holling's Type II model. Under continuous exposure for five days, a significant reduction in consumption was observed with the gravid female from the second day onwards, to a level similar to the number of eggs and larvae consumed by a young female predator

    Multifunctionality of Agriculture Products: Towards Collaborative Policy Guidelines on Sustainable Agro-Related Fuel Development

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    This is an Accepted Manuscript of an article published by Taylor & Francis in Biofuels on 23 January 2017, available online: http://www.tandfonline.com/doi/full/10.1080/17597269.2017.1278930.The primacy of food security overrides that of energy. This is a reasoned view under the United Nations rights-based theories and practice. Within this context, there are voluntary guidelines according to which countries must secure an adequate food supply. Nevertheless, agro-related fuel has recently attracted scientific and commercial attention, following revolutionary thinking concerning the multifunctionality nature of agriculture products and the innovative use of crop resources as conduits in building our energy security and promoting economic growth. Consequently, many countries may be facing the need for strategic decision-making in developing an agro-related fuel programme, given the lack of a credible global framework to inform policy approaches. On the back of this complexity, a key objective of this paper is to provide a critical assessment of whether a credible global collaborative framework can bring much-needed certainty to enable developing countries to weigh up the importance and risks involved and to manage all of the related biodiversity intricacies connected to agro-related policy development in relation to the realisation of sustainable food security.Peer reviewedFinal Accepted Versio

    The State-Moro Armed Conflict in the Philippines: Unresolved national question or question of governance?

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    The continuing struggle of the Moro secessionist movement in the Philippines is one of Southeast Asia’s longest armed conflicts. The tenacity of the conflict lies in two competing concerns: the assertion of self-determination rights of the Moro separatist movement; and the affirmation of the Philippines’ sovereign right to territorial integrity. However, beneath these rights are crucial issues that remain unanswered both by the contending forces—problems where internecine violence and conflict emanate from. This article argues that self-determination rights can be adequately exercised by people who have clearly defined their national identity and concept of a nation. Unfortunately, the Moro multi-ethnic national identity has yet to be crystallised while the idea of a Bangsamoro (Bangsa Nation) remains weak. On the other hand, the state has yet to address the Moros’ legitimate demands of political autonomy, socio-economic development, and social justice and discrimination. Without underestimating the ethnic component of secessionism, the article concludes that poor governance has prolonged, complicated, and further justified the Moros’ quest to secede from the Republic

    Verified and potential pathogens of predatory mites (Acari: Phytoseiidae)

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    Several species of phytoseiid mites (Acari: Phytoseiidae), including species of the genera Amblyseius, Galendromus, Metaseiulus, Neoseiulus, Phytoseiulus and Typhlodromus, are currently reared for biological control of various crop pests and/or as model organisms for the study of predator¿prey interactions. Pathogen-free phytoseiid mites are important to obtain high efficacy in biological pest control and to get reliable data in mite research, as pathogens may affect the performance of their host or alter their reproduction and behaviour. Potential and verified pathogens have been reported for phytoseiid mites during the past 25 years. The present review provides an overview, including potential pathogens with unknown host effects (17 reports), endosymbiotic Wolbachia (seven reports), other bacteria (including Cardinium and Spiroplasma) (four reports), cases of unidentified diseases (three reports) and cases of verified pathogens (six reports). From the latter group four reports refer to Microsporidia, one to a fungus and one to a bacterium. Only five entities have been studied in detail, including Wolbachia infecting seven predatory mite species, other endosymbiotic bacteria infecting Metaseiulus (Galendromus, Typhlodromus) occidentalis (Nesbitt), the bacterium Acaricomes phytoseiuli infecting Phytoseiulus persimilis Athias-Henriot, the microsporidium Microsporidium phytoseiuli infecting P. persimilis and the microsporidium Oligosproridium occidentalis infecting M. occidentalis. In four cases (Wolbachia, A. phytoseiuli, M. phytoseiuli and O. occidentalis) an infection may be connected with fitness costs of the host. Moreover, infection is not always readily visible as no obvious gross symptoms are present. Monitoring of these entities on a routine and continuous basis should therefore get more attention, especially in commercial mass-production. Special attention should be paid to field-collected mites before introduction into the laboratory or mass rearing, and to mites that are exchanged among rearing facilities. However, at present general pathogen monitoring is not yet practical as effects of many entities are unknown. More research effort is needed concerning verified and potential pathogens of commercially reared arthropods and those used as model organisms in research

    A selective retinoid X receptor agonist bexarotene (LGD1069, targretin) inhibits angiogenesis and metastasis in solid tumours

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    The present study determined the influence of a retinoid X receptor agonist bexarotene on angiogenesis and metastasis in solid tumours. In the experimental lung metastasis xenograft models, treatment with bexarotene inhibited the development of the lung tumour nodule formation compared to control. In vivo angiogenesis assay utilising gelfoam sponges, bexarotene reduced angiogenesis in sponges containing vascular endothelial growth factor, epidermal growth factor and basic fibroblast growth factor to various extent. To determine the basis of these observations, human breast and non-small-cell lung cancer cells were subjected to migration and invasion assays in the presence of bexarotene. Our data showed that bexarotene decrease migration and invasiveness of tumour cells in a dose-dependent manner. Furthermore, bexarotene inhibited angiogenesis by directly inhibiting human umbilical vein endothelial cell growth and indirectly inhibiting tumour cell-mediated migration of human umbilical vein endothelial cells through Matrigel matrix. Analysis of tumour-conditioned medium indicated that bexarotene decreased the secretion of angiogenic factors and matrix metalloproteinases and increased the tissue inhibitor of matrix metalloproteinases. The ability of bexarotene to inhibit angiogenesis and metastasis was dependent on activation of its heterodimerisation partner peroxisome proliferator-activated receptor γ. Collectively, our results suggest a role of bexarotene in treatment of angiogenesis and metastasis in solid tumours

    Sensitivity of the Advanced LIGO detectors at the beginning of gravitational wave astronomy

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    The Laser Interferometer Gravitational Wave Observatory (LIGO) consists of two widely separated 4 km laser interferometers designed to detect gravitational waves from distant astrophysical sources in the frequency range from 10 Hz to 10 kHz. The first observation run of the Advanced LIGO detectors started in September 2015 and ended in January 2016. A strain sensitivity of better than 10−23/Hz−−−√ was achieved around 100 Hz. Understanding both the fundamental and the technical noise sources was critical for increasing the astrophysical strain sensitivity. The average distance at which coalescing binary black hole systems with individual masses of 30  M⊙ could be detected above a signal-to-noise ratio (SNR) of 8 was 1.3 Gpc, and the range for binary neutron star inspirals was about 75 Mpc. With respect to the initial detectors, the observable volume of the Universe increased by a factor 69 and 43, respectively. These improvements helped Advanced LIGO to detect the gravitational wave signal from the binary black hole coalescence, known as GW150914

    First all-sky search for continuous gravitational waves from unknown sources in binary systems

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    We present the first results of an all-sky search for continuous gravitational waves from unknown spinning neutron stars in binary systems using LIGO and Virgo data. Using a specially developed analysis program, the TwoSpect algorithm, the search was carried out on data from the sixth LIGO Science Run and the second and third Virgo Science Runs. The search covers a range of frequencies from 20 Hz to 520 Hz, a range of orbital periods from 2 to ~2,254 h and a frequency- and period-dependent range of frequency modulation depths from 0.277 to 100 mHz. This corresponds to a range of projected semi-major axes of the orbit from ~0.6e-3 ls to ~6,500 ls assuming the orbit of the binary is circular. While no plausible candidate gravitational wave events survive the pipeline, upper limits are set on the analyzed data. The most sensitive 95% confidence upper limit obtained on gravitational wave strain is 2.3e-24 at 217 Hz, assuming the source waves are circularly polarized. Although this search has been optimized for circular binary orbits, the upper limits obtained remain valid for orbital eccentricities as large as 0.9. In addition, upper limits are placed on continuous gravitational wave emission from the low-mass x-ray binary Scorpius X-1 between 20 Hz and 57.25 Hz.Comment: 16 pages, 6 figure

    Improved upper limits on the stochastic gravitational-wave background from 2009-2010 LIGO and Virgo data

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    Paper producido por "The LIGO Scientific Collaboration and the Virgo Collaboration". (En el registro se mencionan solo algunos autores de las decenas de personas que participan).Gravitational waves from a variety of sources are predicted to superpose to create a stochastic background. This background is expected to contain unique information from throughout the history of the Universe that is unavailable through standard electromagnetic observations, making its study of fundamental importance to understanding the evolution of the Universe. We carry out a search for the stochastic background with the latest data from the LIGO and Virgo detectors. Consistent with predictions from most stochastic gravitational-wave background models, the data display no evidence of a stochastic gravitational-wave signal. Assuming a gravitational-wave spectrum of ΩGWðfÞ ¼ Ωαðf=frefÞα, we place 95% confidence level upper limits on the energy density of the background in each of four frequency bands spanning 41.5–1726 Hz. In the frequency band of 41.5–169.25 Hz for a spectral index of α¼ 0, we constrain the energy density of the stochastic background to be ΩGWðfÞ <5.6 × 10−6. For the 600–1000 Hz band, ΩGWðfÞ <0.14ðf=900 HzÞ3, a factor of 2.5 lower than the best previously reported upper limits. We find ΩGWðfÞ <1.8 × 10−4 using a spectral index of zero for 170–600 Hz and ΩGWðfÞ < 1.0ðf=1300 HzÞ3 for 1000–1726 Hz, bands in which no previous direct limits have been placed. The limits in these four bands are the lowest direct measurements to date on the stochastic background. We discuss the implications of these results in light of the recent claim by the BICEP2 experiment of the possible evidence for inflationary gravitational waves.http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.113.231101publishedVersionFil: Aasi, J. LIGO. California Institute of Technology; Estados Unidos de América.Fil: Maglione, C. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Maglione, C. Argentinian Gravitational Wave Group; Argentina.Fil: Quiroga, G. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Quiroga, G. Argentinian Gravitational Wave Group; Argentina.Física de Partículas y Campo

    A Low Concentration of Ethanol Impairs Learning but Not Motor and Sensory Behavior in Drosophila Larvae

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    Drosophila melanogaster has proven to be a useful model system for the genetic analysis of ethanol-associated behaviors. However, past studies have focused on the response of the adult fly to large, and often sedating, doses of ethanol. The pharmacological effects of low and moderate quantities of ethanol have remained understudied. In this study, we tested the acute effects of low doses of ethanol (∼7 mM internal concentration) on Drosophila larvae. While ethanol did not affect locomotion or the response to an odorant, we observed that ethanol impaired associative olfactory learning when the heat shock unconditioned stimulus (US) intensity was low but not when the heat shock US intensity was high. We determined that the reduction in learning at low US intensity was not a result of ethanol anesthesia since ethanol-treated larvae responded to the heat shock in the same manner as untreated animals. Instead, low doses of ethanol likely impair the neuronal plasticity that underlies olfactory associative learning. This impairment in learning was reversible indicating that exposure to low doses of ethanol does not leave any long lasting behavioral or physiological effects

    Identifying Where REDD+ Financially Out Competes Oil Palm in Floodplain Landscapes Using a Fine-Scale Approach

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    Reducing Emissions from Deforestation and forest Degradation (REDD+) aims to avoid forest conversion to alternative land-uses through financial incentives. Oil-palm has high opportunity costs, which according to current literature questions the financial competitiveness of REDD+ in tropical lowlands. To understand this more, we undertook regional finescale and coarse-scale analyses (through carbon mapping and economic modelling) to assess the financial viability of REDD+ in safeguarding unprotected forest (30,173 ha) in the Lower Kinabatangan floodplain in Malaysian Borneo. Results estimate 4.7 million metric tons of carbon (MgC) in unprotected forest, with 64% allocated for oil-palm cultivations. Through fine-scale mapping and carbon accounting, we demonstrated that REDD+ can outcompete oil-palm in regions with low suitability, with low carbon prices and low carbon stock. In areas with medium oil-palm suitability, REDD+ could outcompete oil palm in areas with: very high carbon and lower carbon price; medium carbon price and average carbon stock; or, low carbon stock and high carbon price. Areas with high oil palm suitability, REDD + could only outcompete with higher carbon price and higher carbon stock. In the coarse-scale model, oil-palm outcompeted REDD+ in all cases. For the fine-scale models at the landscape level, low carbon offset prices (US 3MgCO2e)wouldenableREDD+tooutcompeteoilpalmin553 MgCO2e) would enable REDD+ to outcompete oil-palm in 55% of the unprotected forests requiring US 27 million to secure these areas for 25 years. Higher carbon offset price (US 30MgCO2e)wouldincreasethecompetitivenessofREDD+withinthelandscapebutwouldstillonlycapturebetween6930 MgCO2e) would increase the competitiveness of REDD+ within the landscape but would still only capture between 69%-74% of the unprotected forest, requiring US 380–416 million in carbon financing. REDD+ has been identified as a strategy to mitigate climate change by many countries (including Malaysia). Although REDD+ in certain scenarios cannot outcompete oil palm, this research contributes to the global REDD+ debate by: highlighting REDD+ competitiveness in tropical floodplain landscapes; and, providing a robust approach for identifying and targeting limited REDD+ funds
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