6,518 research outputs found

    Will the real Bemisia tabaci please stand up?

    Get PDF
    Since Panayiotis Gennadius first identified the whitefly, Aleyrodes tabaci in 1889, there have been numerous revisions of the taxonomy of what has since become one of the world’s most damaging insect pests. Most of the taxonomic revisions have been based on synonymising different species under the name Bemisia tabaci. It is now considered that there is sufficient biological, behavioural and molecular genetic data to support its being a cryptic species complex composed of at least 34 morphologically indistinguishable species. The first step in revising the taxonomy of this complex involves matching the A. tabaci collected in 1889 to one of the members of the species complex using molecular genetic data. To do this we extracted and then amplified a 496 bp fragment from the 39 end of the mitochondrial DNA cytochrome oxidase one (mtCOI) gene belonging to a single whitefly taken from Gennadius’ original 1889 collection. The sequence identity of this 123 year-old specimen enabled unambiguous assignment to a single haplotype known from 13 Mediterranean locations across Greece and Tunisia. This enabled us to unambiguously assign the Gennadius A. tabaci to the member of the B. tabaci cryptic species complex known as Mediterranean or as it is commonly, but erroneously referred to, as the ‘Q-biotype’. Mediterranean is therefore the real B. tabaci. This study demonstrates the importance of matching museum syntypes with known species to assist in the delimitation of cryptic species based on the organism’s biology and molecular genetic data. This study is the first step towards the reclassification of B. tabaci which is central to an improved understanding how best to manage this globally important agricultural and horticultural insect pest complex

    Audition in vampire bats, Desmodus rotundus

    Get PDF
    1. Within the tonotopic organization of the inferior colliculus two frequency ranges are well represented: a frequency range within that of the echolocation signals from 50 to 100 kHz, and a frequency band below that of the echolocation sounds, from 10 to 35 kHz. The frequency range between these two bands, from about 40 to 50 kHz is distinctly underrepresented (Fig. 3B). 2. Units with BFs in the lower frequency range (10–25 kHz) were most sensitive with thresholds of -5 to -11 dB SPL, and units with BFs within the frequency range of the echolocation signals had minimal thresholds around 0 dB SPL (Fig. 1). 3. In the medial part of the rostral inferior colliculus units were encountered which preferentially or exclusively responded to noise stimuli. — Seven neurons were found which were only excited by human breathing noises and not by pure tones, frequency modulated signals or various noise bands. These neurons were considered as a subspeciality of the larger sample of noise-sensitive neurons. — The maximal auditory sensitivity in the frequency range below that of echolocation, and the conspicuous existence of noise and breathing-noise sensitive units in the inferior colliculus are discussed in context with the foraging behavior of vampire bats

    Combined measurements of prey availability explain habitat selection in foraging seabirds

    Get PDF
    Understanding links between habitat characteristics and foraging efficiency helps predict how environmental changes influence populations of top predators. This study examines whether measurements of prey (clupeids) availability varied over stratification gradients, and determined if any of those measurements coincided with aggregations of foraging seabirds (common guillemot Uria aalge and Manx shearwater Puffinus puffinus) in the Celtic Sea, UK. The probability of encountering foraging seabirds was highest around fronts between mixed and stratified water. Prey were denser and shallower in mixed water, whilst encounters with prey were most frequent in stratified water. Therefore, no single measurement of increased prey availability coincided with the location of fronts. However, when considered in combination, overall prey availability was highest in these areas. These results show that top predators may select foraging habitats by trading-off several measurements of prey availability. By showing that top predators select areas where prey switch between behaviours, these results also identify a mechanism that could explain the wider importance of edge habitats for these taxa. As offshore developments (e.g. marine renewable energy installations) change patterns of stratification, their construction may have consequences on the foraging efficiency of seabirds

    The impact of SARS-CoV-2 vaccination in Dravet Syndrome: A UK survey

    Get PDF
    Background: The COVID-19 pandemic led to the urgent need for accelerated vaccine development. Approved vaccines have proved to be safe and well tolerated across millions of people in the general population. Dravet Syndrome (DS) is a severe, early onset, developmental and epileptic encephalopathy. Vaccination is a precipitating factor for seizures. Whilst there is no evidence that vaccine-precipitated seizures lead to adverse outcomes in people with DS, fear surrounding vaccination can remain for caregivers of people with DS, in some cases resulting in rejection of recommended vaccinations, leaving individuals more vulnerable to the relevant infections. A greater understanding of the safety profile of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination in this vulnerable group will help provide guidance for caregivers and clinicians when considering vaccination. / Methods: A cross‐sectional survey regarding COVID-19 and SARS-CoV-2 vaccine, in people with DS, was conducted by Dravet Syndrome UK (DSUK). Concomitantly, a review of individuals with DS who had recently received the SARS-CoV-2 vaccine, and who are resident at the Chalfont Centre for Epilepsy (CCE), or attend epilepsy clinics at the National Hospital for Neurology and Neurosurgery (NHNN), was undertaken. / Results: 38 people completed the DSUK survey. 37% of caregivers reported being concerned about someone with DS receiving the SARS-CoV-2 vaccine; with some reporting that they would decline a vaccine when offered. 77% had not received any advice from a health care professional about the SARS-CoV-2 vaccination. 18/38 were eligible for SARS-CoV-2 vaccination, of whom nine had received their first vaccine dose. Combining the results of the DSUK survey and the review of individuals monitored at CCE or NHNN, fifteen people with DS had received their first dose of the SARS-CoV-2 vaccine. 11/15 (73%) reported at least one side effect, the most common being fatigue (6/15; 40%) and fever (6/15; 40%). Three individuals (20%) reported an increase in seizure frequency after the first vaccine dose. No increase in seizure frequency or duration was reported after the second dose. / Conclusion: Overall, these results suggest that SARS-CoV-2 vaccines are safe and well tolerated in individuals with DS, as they are in most people without DS. In most people with DS, SARS-CoV-2 vaccine does not appear to be associated with an increase in the frequency or duration of seizures, even in those who develop fever post-vaccination. Many caregivers are concerned about a person with DS receiving a SARS-CoV-2 vaccine, with some reporting that they would decline a SARS-CoV-2 vaccine when offered. It is crucial that healthcare professionals are proactive in providing accurate information regarding the risks and benefits of vaccination in this population, given the potential for serious outcomes from infection

    Absence of renal hypoxia in the subacute phase of severe renal ischemia reperfusion injury

    Get PDF
     This is the author accepted manuscript. The final version is available from American Physiological Society via the DOI in this recordTissue hypoxia has been proposed as an important event in renal ischemia reperfusion injury (IRI) particularly during the period of ischemia and in the immediate hours following reperfusion. However, little is known about renal oxygenation during the subacute phase of IRI. We employed four different methods to assess the temporal and spatial changes in tissue oxygenation during the subacute phase (24 h and 5 days after reperfusion) of a severe form of renal IRI in rats. We hypothesized that the kidney is hypoxic 24 h and 5 days after an hour of bilateral renal ischemia, driven by a disturbed balance between renal oxygen delivery (DO2) and oxygen consumption (VO2). Renal DO2 was not significantly reduced in the subacute phase of IRI. In contrast, renal VO2 was 55% less 24 h, and 49% less 5 days after reperfusion than after sham-ischemia. Inner medullary tissue PO2, measured by radiotelemetry was 25 {plus minus} 12% greater 24 h after ischemia than after sham-ischemia. By 5 days after reperfusion, tissue PO2 was similar to that in rats subjected to sham-ischemia. Tissue PO2 measured by Clark electrode was consistently greater 24 h, but not 5 days, after ischemia than after sham-ischemia. Cellular hypoxia, assessed by pimonidazole adduct immunohistochemistry, was largely absent at both time-points and tissue levels of hypoxia inducible factors were downregulated following renal ischemia. Thus, in this model of severe IRI, tissue hypoxia does not appear to be an obligatory event during the subacute phase, likely due to the markedly reduced oxygen consumption.British Heart FoundationBritish Heart FoundationNational Health and Medical Research Council of AustraliaEuropean Union, Seventh Framework Programm

    Spatially Resolved Magnetic Field Structure in the Disk of a T Tauri Star

    Get PDF
    Magnetic fields in accretion disks play a dominant role during the star formation process but have hitherto been observationally poorly constrained. Field strengths have been inferred on T Tauri stars themselves and possibly in the innermost part of the accretion disk, but the strength and morphology of the field in the bulk of the disk have not been observed. Unresolved measurements of polarized emission (arising from elongated dust grains aligned perpendicular to the field) imply average fields aligned with the disks. Theoretically, the fields are expected to be largely toroidal, poloidal, or a mixture of the two, which imply different mechanisms for transporting angular momentum in the disks of actively accreting young stars such as HL Tau. Here we report resolved measurements of the polarized 1.25 mm continuum emission from HL Tau's disk. The magnetic field on a scale of 80 AU is coincident with the major axis (~210 AU diameter) of the disk. From this we conclude that the magnetic field inside the disk at this scale cannot be dominated by a vertical component, though a purely toroidal field does not fit the data well either. The unexpected morphology suggests that the magnetic field's role for the accretion of a T Tauri star is more complex than the current theoretical understanding.Comment: Accepted for publication in Natur

    Simplified R-Symmetry Breaking and Low-Scale Gauge Mediation

    Full text link
    We argue that some of the difficulties in constructing realistic models of low-scale gauge mediation are artifacts of the narrow set of models that have been studied. In particular, much attention has been payed to the scenario in which the Goldstino superfield in an O'Raifeartaigh model is responsible for both supersymmetry breaking and R-symmetry breaking. In such models, the competing problems of generating sufficiently massive gauginos while preserving an acceptably light gravitino can be quite challenging. We show that by sharing the burdens of breaking supersymmetry and R-symmetry with a second field, these problems are easily solved even within the O'Raifeartaigh framework. We present explicit models realizing minimal gauge mediation with a gravitino mass in the eV range that are both calculable and falsifiable.Comment: 31 pages, 4 figures, references added, minor change

    Breast cancer risk reduction:is it feasible to initiate a randomised controlled trial of a lifestyle intervention programme (ActWell) within a national breast screening programme?

    Get PDF
    BackgroundBreast cancer is the most commonly diagnosed cancer and the second cause of cancer deaths amongst women in the UK. The incidence of the disease is increasing and is highest in women from least deprived areas. It is estimated that around 42% of the disease in post-menopausal women could be prevented by increased physical activity and reductions in alcohol intake and body fatness. Breast cancer control endeavours focus on national screening programmes but these do not include communications or interventions for risk reductionThis study aimed to assess the feasibility of delivery, indicative effects and acceptability of a lifestyle intervention programme initiated within the NHS Scottish Breast Screening Programme (NHSSBSP).MethodsA 1:1 randomised controlled trial (RCT) of the 3 month ActWell programme (focussing on body weight, physical activity and alcohol) versus usual care conducted in two NHSSBSP sites between June 2013 and January 2014. Feasibility assessments included recruitment, retention, and fidelity to protocol. Indicative outcomes were measured at baseline and 3 month follow-up (body weight, waist circumference, eating and alcohol habits and physical activity. At study end, a questionnaire assessed participant satisfaction and qualitative interviews elicited women¿s, coaches and radiographers¿ experiences. Statistical analysis used Chi squared tests for comparisons in proportions and paired t tests for comparisons of means. Linear regression analyses were performed, adjusted for baseline values, with group allocation as a fixed effectResultsA pre-set recruitment target of 80 women was achieved within 12 weeks and 65 (81%) participants (29 intervention, 36 control) completed 3 month assessments. Mean age was 58¿±¿5.6 years, mean BMI was 29.2¿±¿7.0 kg/m2 and many (44%) reported a family history of breast cancer.The primary analysis (baseline body weight adjusted) showed a significant between group difference favouring the intervention group of 2.04 kg (95%CI ¿3.24 kg to ¿0.85 kg). Significant, favourable between group differences were also detected for BMI, waist circumference, physical activity and sitting time. Women rated the programme highly and 70% said they would recommend it to others.ConclusionsRecruitment, retention, indicative results and participant acceptability support the development of a definitive RCT to measure long term effects.Trial registrationThe trial was registered with Current Controlled Trials (ISRCTN56223933)
    corecore