3,183 research outputs found

    Seasonal density estimates of common large herbivores in Hwange National Park, Zimbabwe

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    The monitoring of ecosystem processes and states is a critical step in the management of protected areas. It allows for the assessment of the success or failure of practices ranging from ‘laissez-faire’ to strong hands-on policies. Much effort is for instance devoted to the monitoring of wildlife abundance, particularly when associated with large ecological influence or socio-economical values (Gordon, Hester & Festa-Bianchet, 2004). In Africa, the diversity of large herbivores represents both a major asset of protected areas and a global conservation target as a consequence of the dramatic decline of wildlife populations under other land uses. In addition to the local importance of such monitoring data, collation of data from multiple sites ultimately allows general patterns to be revealed (e.g. Fritz & Duncan, 1994). Here, we contribute to the general knowledge on large African herbivores by reporting on their seasonal abundance, using road transect counts, in Hwange National Park (thereafter HNP), north-western Zimbabwe

    Endoscopy and Cannulation as Non-Invasive Tools to Identify Sex and Monitor Reproductive Development in Arapaima gigas

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    The lack of tools for sex identification and assessment of gonadal development are hindering our ability to study the reproductive dysfunction of Arapaima gigas in captivity. This study initially aimed to validate a non-surgical endoscopy procedure to identify sex in juveniles and assess stage of ovary development in female broodstock under field operational conditions. Cannulation, assisted through the description of the genital anatomy, made ovarian biopsy possible to describe oocyte development from primary growth to pre-ovulation, providing a first classification scheme for oogenesis in the species including description of the micropyle morphology using scanning electron microscopy. Cannulation was also successfully performed without endoscopic guidance, which allowed monitoring of ovarian development along the reproductive season together with profiling of plasma sex steroids (17β-estradiol [E2] and 11-ketotestosterone [11-KT] in females and males, respectively). The monitoring of our study population showed females paired with males in earthen ponds sexually matured and reached oocyte maturation during the spawning season. However, since no spawning was recorded, eggs had either been resorbed or released and not fertilized by the male. Plasma E2 levels remained high in females, as expected in an asynchronous species during the spawning season with multiple batches of oocytes being recruited. Plasma 11-KT showed a tendency to decrease, suggesting a male reproductive dysfunction or the end of the reproductive season with a lack of synchronization between sexes. In conclusion, endoscopy and cannulation are tools that can be promptly applied to aid sex identification, assessment of reproductive function, and overall broodstock management in wild and captive stocks. These tools will greatly help future studies looking at the effects of environmental, social, and hormonal cues on reproductive development with the aim of developing a spawning induction protocol for the species

    Mapping CO Gas in the GG Tauri A Triple System with 50 AU Spatial Resolution

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    We aim to unveil the observational imprint of physical mechanisms that govern planetary formation in the young, multiple system GG Tau A. We present ALMA observations of 12^{12}CO and 13^{13}CO 3-2 and 0.9 mm continuum emission with 0.35" resolution. The 12^{12}CO 3-2 emission, found within the cavity of the circumternary dust ring (at radius <180< 180 AU) where no 13^{13}CO emission is detected, confirms the presence of CO gas near the circumstellar disk of GG Tau Aa. The outer disk and the recently detected hot spot lying at the outer edge of the dust ring are mapped both in 12^{12}CO and 13^{13}CO. The gas emission in the outer disk can be radially decomposed as a series of slightly overlapping Gaussian rings, suggesting the presence of unresolved gaps or dips. The dip closest to the disk center lies at a radius very close to the hot spot location at 250260\sim250-260~AU. The CO excitation conditions indicate that the outer disk remains in the shadow of the ring. The hot spot probably results from local heating processes. The two latter points reinforce the hypothesis that the hot spot is created by an embedded proto-planet shepherding the outer disk.Comment: 8 pages, 4 figures. Accepted by Ap

    Impact of freshwater rearing history on Atlantic salmon gill response to viral stimulation post seawater transfer

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    The authors would like to thank John Richmond and staff at MOWI. Special thanks also to the staff at Machrihanish for their assistance in sample collection during a challenging time. • RAS and LOCH reared fish differ in baseline immune transcriptome post-SWT • LOCH fish have higher steady state immune gene mRNA levels post-SWT • RAS fish mount a greater magnitude of transcriptomic response to viral stimulation • RAS fish ‘catch-up’ via compensatory mechanisms or may mount an excessive responsePeer reviewe

    Long-term field-realistic exposure to a next-generation pesticide, flupyradifurone, impairs honey bee behaviour and survival

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    10openInternationalInternational coauthor/editorThe assessment of pesticide risks to insect pollinators have typically focused on short-term, lethal impacts. The environmental ramifications of many of the world’s most commonly employed pesticides, such as those exhibiting systemic properties that can result in long-lasting exposure to insects, may thus be severely underestimated. Here, seven laboratories from Europe and North America performed a standardised experiment (a ring-test) to study the long-term lethal and sublethal impacts of the relatively recently approved ‘bee safe’ butenolide pesticide flupyradifurone (FPF, active ingredient in Sivanto®) on honey bees. The emerging contaminant, FPF, impaired bee survival and behaviour at field-realistic doses (down to 11 ng/bee/day, corresponding to 400 µg/kg) that were up to 101-fold lower than those reported by risk assessments (1110 ng/bee/day), despite an absence of time-reinforced toxicity. Our findings raise concerns about the chronic impact of pesticides on pollinators at a global scale and support a novel methodology for a refined risk assessmentopenTosi, Simone; Nieh, James C; Brandt, Annely; Colli, Monica; Fourrier, Julie; Giffard, Herve; Hernández-López, Javier; Malagnini, Valeria; Williams, Geoffrey R; Simon-Delso, NoaTosi, S.; Nieh, J.C.; Brandt, A.; Colli, M.; Fourrier, J.; Giffard, H.; Hernández-López, J.; Malagnini, V.; Williams, G.R.; Simon-Delso, N

    The EDELWEISS Experiment : Status and Outlook

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    The EDELWEISS Dark Matter search uses low-temperature Ge detectors with heat and ionisation read- out to identify nuclear recoils induced by elastic collisions with WIMPs from the galactic halo. Results from the operation of 70 g and 320 g Ge detectors in the low-background environment of the Modane Underground Laboratory (LSM) are presented.Comment: International Conference on Dark Matter in Astro and Particle Physics (Dark 2000), Heidelberg, Germany, 10-16 Jul 2000, v3 minor revision

    Multiplying the efficiency and impact of biofortification through metabolic engineering

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    Ending all forms of hunger by 2030, as set forward in the UN-Sustainable Development Goal 2 (UN-SDG2), is a daunting but essential task, given the limited timeline ahead and the negative global health and socio-economic impact of hunger. Malnutrition or hidden hunger due to micronutrient deficiencies affects about one third of the world population and severely jeopardizes economic development. Staple crop biofortification through gene stacking, using a rational combination of conventional breeding and metabolic engineering strategies, should enable a leap forward within the coming decade. A number of specific actions and policy interventions are proposed to reach this goal

    Evolution of antibiotic treatments for healthcare-associated infections caused by extended-spectrum beta-lactamase-producing Enterobacteriaceae in France

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    BACKGROUND: Infections caused by extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBLE) remain a public health challenge. AIM: We traced the evolution of antibiotics prescribed for patients with ESBLE-healthcare associated infections (ESBLE-HAI) between 2012 and 2017, with a specific focus on treatments for lower urinary tract infections (LUTI). METHODS: We used the 2012 and 2017 French point prevalence survey data. Patients with ESBLE-HAI were defined as those diagnosed with at least one Enterobacteriaceae with ESBL production. Patients with LUTI caused by ESBLE (ESBLE-LUTI) were defined as those with LUTI as the reported infection site and diagnosed with ESBLE. We only analysed treatments intended for HAI. RESULTS: In 2017, more than half of treatments for ESBLE-HAIs were β-lactams. While from 2012 to 2017 the proportion of carbapenem treatments decreased from 30% to 25%, penicillin treatments doubled. Among patients treated for ESBLE-LUTI, a larger proportion received a single antibiotic in 2017. The most frequently prescribed antibiotics for these infections were amoxicillin/clavulanic acid, nitrofurantoin and ofloxacin. More than one out of six treatments lasted for more than 7 days. Carbapenem use was halved between 2012 and 2017, and decreases were likewise observed for aminoglycosides. CONCLUSION: In accordance with French recommendations, comparison of the two most recent French point prevalence surveys showed an evolution in ESBLE-HAI treatment, especially for ESBLE-LUTI. However, treatment durations remained longer than recommended. Data from the 2022 survey should provide insights on the future evolution of prescription trends
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