742 research outputs found

    Determination of fipronil LD50 for the brazilian bee Melipona scutellaris

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    To better understand the sensitivity of the models represented by Apis mellifera L., 1758 in toxicology studies of insecticides to bees, the aim of this study was to determine the LD50 of fipronil by topical application on the stingless bees Melipona scutellaris Latreille, 1811. Foraging bees were collected at the nest entrance and in laboratory anesthetized with CO2 for applying 1.0 μL of fipronil solution on the pronotum. Each group of treatments was made with thirteen bees divided in three cages, while in the control treatments the bees received only acetone. During the assay, the behavior and the number of dead bees were registered. The results showed that the insecticide fipronil applied topically was harmful to M. scutellaris and for A. mellifera, where the LD50 for 48 hours was 0.41 ng a.i./bee or 4.1 ng a.i./ g of bee. Comparing the LD50 values here obtained with the stingless bee M. scutellaris and those of A. mellifera in literature, we can conclude that the native bees are more sensitive to fipronil than the allochtonous bee, suggesting that further studies should be accomplished to determine the real hazard of pesticides to natives bees. Keywords: stingless bees, pesticides, phenylpyrazole, toxicity, LD5

    Y-chromosomal variation in the Czech Republic

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    To analyze the contribution of the Czech population to the Y-chromosome diversity landscape of Europe and to reconstruct past demographic events, we typed 257 males from five locations for 21 UEPs. Moreover, 141 carriers of the three most common haplogroups were typed for 10 microsatellites and coalescent analyses applied. Sixteen Hg's characterized by derived alleles were identified, the most common being R1a-SRY10831 and P-DYS257*(xR1a). The pool of haplogroups within I-M170 represented the third most common clade. Overall, the degree of population structure was low. The ages for Hg I-M170, P-DYS257*(xR1a), and R1a-SRY10831 appeared to be comparable and compatible with their presence during or soon after the LGM. A signal of population growth beginning in the first millennium B.C. was detected. Its similarity among the three most common Hg's indicated that growth was characteristic for a gene pool that already contained all of them. The Czech population appears to be influenced, to a very moderate extent, by genetic inputs from outside Europe in the post-Neolithic and historical times. Population growth postdated the archaeologically documented introduction of Neolithic technology and the estimated central value coincides with a period of repeated changes driven by the development of metal technologies and the associated social and trade organization

    AREA VULCANICA NAPOLETANA: 10 ANNI DI OSSERVAZIONI GPS

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    L’area napoletana è una delle zone a più alto rischio vulcanico, per la presenza di tre strutture vulcaniche attive (il Somma-Vesuvio, la caldera dei Campi Flegrei e l’Isola d’Ischia) e per l’intensa urbanizzazione della zona. La concentrazione dei suddetti vulcani attivi in un’area molto urbanizzata rende fondamentale la presenza di un sistema di monitoraggio che registri i fenomeni connessi al processo vulcanico in atto e che dia informazioni utili per modellarne il comportamento. Tra i vari fenomeni che generalmente sono associati ai processi vulcanici, le deformazioni statiche giocano un ruolo importante per lo studio dei parametri delle sorgenti magmatiche e per la loro modellazione. Nell’area vulcanica napoletana è presente una estesa rete GPS (sia permanente che discreta) che negli ultimi 10 anni ha permesso di raccogliere una mole importante di dati e di avere informazioni circa la dinamica in atto. I dati raccolti in tale periodo, a causa dei rapidi sviluppi della tecnologia GPS, della strumentazione, delle metodologie di processamento, presentavano alcune disomogeneità nella qualità, nell’archiviazione e nell’elaborazione. Pertanto è stato necessario un notevole lavoro di verifica, correzione ed omogeneizzazione dal punto di vista qualitativo di tutti i dati disponibili. Successivamente si è potuto procedere al riprocessamento dei dati, utilizzando il software GPS Bernese v. 5.0, secondo i più recenti standard IGS. Questo lavoro ha permesso di creare un database accurato di tutti i dati GPS disponibili per l’intera area vulcanica napoletana e il conseguente miglioramento della qualità dei risultati ha fornito un utile contributo all’interpretazione dei movimenti del suolo avvenuti negli ultimi anni. In particolare, i nuovi dati ottenuti hanno permesso un’accurata descrizione dell’andamento temporale dei modesti fenomeni di sollevamento (mini-uplift) che hanno interessato la caldera flegrea negli ultimi anni

    The omega-3 fatty acid eicosapentaenoic acid accelerates disease progression in a model of amyotrophic lateral sclerosis.

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    Amyotrophic lateral sclerosis (ALS) is a progressive fatal neurodegenerative disease characterised by loss of motor neurons that currently has no cure. Omega-3 polyunsaturated fatty acids, such as eicosapentaenoic acid (EPA), have many health benefits including neuroprotective and myoprotective potential. We tested the hypothesis that a high level of dietary EPA could exert beneficial effects in ALS. The dietary exposure to EPA (300 mg/kg/day) in a well-established mouse model of ALS expressing the G93A superoxide dismutase 1 (SOD1) mutation was initiated at a pre-symptomatic or symptomatic stage, and the disease progression was monitored until the end stage. Daily dietary EPA exposure initiated at the disease onset did not significantly alter disease presentation and progression. In contrast, EPA treatment initiated at the pre-symptomatic stage induced a significantly shorter lifespan. In a separate group of animals sacrificed before the end stage, the tissue analysis showed that the vacuolisation detected in G93A-SOD1 mice was significantly increased by exposure to EPA. Although EPA did not alter motor neurone loss, EPA reversed the significant increase in activated microglia and the astrocytic activation seen in G93A-SOD1 mice. The microglia in the spinal cord of G93A-SOD1 mice treated with EPA showed a significant increase in 4-hydroxy-2-hexenal, a highly toxic aldehydic oxidation product of omega-3 fatty acids. These data show that dietary EPA supplementation in ALS has the potential to worsen the condition and accelerate the disease progression. This suggests that great caution should be exerted when considering dietary omega-3 fatty acid supplements in ALS patients

    Whistler Wave Observations by \textit{Parker Solar Probe} During Encounter 11: Counter-Propagating Whistlers Collocated with Magnetic Field Inhomogeneities and their Application to Electric Field Measurement Calibration

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    Observations of the young solar wind by the Parker Solar Probe (PSP) mission reveal the existence of intense plasma wave bursts with frequencies between 0.050.05 -- 0.20fce0.20 f_\mathrm{ce} (tens of Hz up to 300{\sim}300 Hz) in the spacecraft frame. The wave bursts are often collocated with inhomogeneities in the solar wind magnetic field, such as local dips in magnitude or sudden directional changes. The observed waves are identified as electromagnetic whistler waves that propagate either sunward, anti-sunward, or in counter-propagating configurations during different burst events. Being generated in the solar wind flow the waves experience significant Doppler down-shift and up-shift {of wave frequency} in the spacecraft frame for sunward and anti-sunward waves, respectively. Their peak amplitudes can be larger than 22~nT, where such values represent up to 10%10\% of the background magnetic field during the interval of study. The amplitude is maximum for propagation parallel to the background magnetic field. We (i) evaluate the properties of these waves by reconstructing their parameters in the plasma frame, (ii) estimate the effective length of the PSP electric field antennas at whistler frequencies, and (iii) discuss the generation mechanism of these waves

    Observations of Energetic-particle Population Enhancements along Intermittent Structures near the Sun from the Parker Solar Probe

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    Observations at 1 au have confirmed that enhancements in measured energetic-particle (EP) fluxes are statistically associated with "rough" magnetic fields, i.e., fields with atypically large spatial derivatives or increments, as measured by the Partial Variance of Increments (PVI) method. One way to interpret this observation is as an association of the EPs with trapping or channeling within magnetic flux tubes, possibly near their boundaries. However, it remains unclear whether this association is a transport or local effect; i.e., the particles might have been energized at a distant location, perhaps by shocks or reconnection, or they might experience local energization or re-acceleration. The Parker Solar Probe (PSP), even in its first two orbits, offers a unique opportunity to study this statistical correlation closer to the corona. As a first step, we analyze the separate correlation properties of the EPs measured by the Integrated Science Investigation of the Sun (IS⊙IS) instruments during the first solar encounter. The distribution of time intervals between a specific type of event, i.e., the waiting time, can indicate the nature of the underlying process. We find that the IS⊙IS observations show a power-law distribution of waiting times, indicating a correlated (non-Poisson) distribution. Analysis of low-energy (~15 – 200 keV/nuc) IS⊙IS data suggests that the results are consistent with the 1 au studies, although we find hints of some unexpected behavior. A more complete understanding of these statistical distributions will provide valuable insights into the origin and propagation of solar EPs, a picture that should become clear with future PSP orbits

    Prospective study on the effect of short-term androgen deprivation therapy on PSMA uptake evaluated with 68Ga-PSMA-11 PET/MRI in men with treatment-naïve prostate cancer

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    PURPOSE: Based on in vitro studies, it is known that androgen deprivation therapy (ADT) increases prostate-specific membrane antigen (PSMA) expression. Therefore, we hypothesised that ADT improves the performance of PSMA-PET imaging in primary staging of prostate cancer. The purpose of the study was to demonstrate the time course effect of ADT on PSMA uptake in different types of metastatic lesions evaluated with 68Ga-PSMA-11 PET/MRI.METHODS: Nine men with treatment-naïve prostate cancer were enrolled to a prospective, registered (NCT03313726) clinical trial. A 68Ga-PSMA-11 PET/MRI was performed once before and 3 times post-ADT (degarelix, Firmagon). Change of maximum standardised uptake values (SUVmax) in prostate, lymph nodes, bone metastases, and physiologically PSMA-avid organs were evaluated in a time frame of 1-8 weeks.RESULTS: All patients reached castration levels within 10 days, and 50% decrease in prostate-specific antigen (PSA) concentration was observed 14 days post-ADT. A heterogeneous increase in PSMA uptake was observed 3 to 4 weeks post-ADT. This phenomenon was definitively more evident in bone metastases: 13 (57%) of the metastasis, with a mean (range) SUVmax increase of 77% (8-238%). In one patient, already having bone metastases at baseline, three new bone metastases were observed post-ADT. Of lesions with reduced SUVmax, none disappeared.CONCLUSIONS: Both in patient and region level, increase in PSMA uptake post-ADT is heterogenous and is seen most evidently in bone metastases. Preliminary results on a small cohort of patients suggest the clinical impact of ADT on improving the performance of 68Ga-PSMA PET in staging seems to be minor. However, the optimal imaging time point might be 3 to 4 weeks post-ADT. Since none of the metastases with decreasing SUVmax disappeared, it seems that short-term usage of ADT does not interfere with the interpretation of 68Ga-PSMA PET.TRIAL REGISTRATION: NCT03313726, registered 18 October 2017; EUDRA-CT, 2017-002345-29.</p

    Teaching Energy Efficiency: A Cross-Border Public Class and Lesson Study in STEM

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    As part of an APEC educational project on the cross-cutting concept of energy, researchers and teachers from 6 countries spent 8 months designing, testing and implementing a pilot STEM public class with two schools from Chile and one from the US. One of the researchers taught a lesson from a school in Chile, with a live transmission to the other two schools via Skype. At the same time, the lesson was also broadcasted via video streaming. In addition to live questions and answers, students used individual devices to answer four open-ended questions that were commented on by the researcher as he received them. The experience demonstrated that Cross-Border Public Classes boost student engagement and represent a promising strategy for introducing a key 21st century skill: synchronous learning involving multiple teams across the world. It also revealed how Lesson Study and Public Classes integrated with ICT network technology can form a powerful learning ecosystem for regional development and social innovation
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