Magnetic-field-induced charge redistribution in disordered graphene double quantum dots

We have studied the transport properties of a large graphene double quantum dot under the influence of a background disorder potential and a magnetic field. At low temperatures, the evolution of the charge-stability diagram as a function of the B field is investigated up to 10 T. Our results indicate that the charging energy of the quantum dot is reduced, and hence the effective size of the dot increases at a high magnetic field. We provide an explanation of our results using a tight-binding model, which describes the charge redistribution in a disordered graphene quantum dot via the formation of Landau levels and edge states. Our model suggests that the tunnel barriers separating different electron/hole puddles in a dot become transparent at high B fields, resulting in the charge delocalization and reduced charging energy observed experimentally.This work was financially supported by the European GRAND project (ICT/FET, Contract No. 215752) and EPSRC

Vitamin A supplementation in Tanzania: the impact of a change in programmatic delivery strategy on coverage.

BACKGROUND\ud \ud Efficient delivery strategies for health interventions are essential for high and sustainable coverage. We report impact of a change in programmatic delivery strategy from routine delivery through the Expanded Programme on Immunization (EPI+) approach to twice-yearly mass distribution campaigns on coverage of vitamin A supplementation in Tanzania\ud \ud METHODS\ud \ud We investigated disparities in age, sex, socio-economic status, nutritional status and maternal education within vitamin A coverage in children between 1 and 2 years of age from two independent household level child health surveys conducted (1) during a continuous universal targeting scheme based on routine EPI contacts for children aged 9, 15 and 21 months (1999); and (2) three years later after the introduction of twice-yearly vitamin A supplementation campaigns for children aged 6 months to 5 years, a 6-monthly universal targeting scheme (2002). A representative cluster sample of approximately 2,400 rural households was obtained from Rufiji, Morogoro Rural, Kilombero and Ulanga districts. A modular questionnaire about the health of all children under the age of five was administered to consenting heads of households and caretakers of children. Information on the use of child health interventions including vitamin A was asked.\ud \ud RESULTS\ud \ud Coverage of vitamin A supplementation among 1-2 year old children increased from 13% [95% CI 10-18%] in 1999 to 76% [95%CI 72-81%] in 2002. In 2002 knowledge of two or more child health danger signs was negatively associated with vitamin A supplementation coverage (80% versus 70%) (p = 0.04). Nevertheless, we did not find any disparities in coverage of vitamin A by district, gender, socio-economic status and DPT vaccinations.\ud \ud CONCLUSION\ud \ud Change in programmatic delivery of vitamin A supplementation was associated with a major improvement in coverage in Tanzania that was been sustained by repeated campaigns for at least three years. There is a need to monitor the effect of such campaigns on the routine health system and on equity of coverage. Documentation of vitamin A supplementation campaign contacts on routine maternal and child health cards would be a simple step to facilitate this monitoring

Transport spectroscopy of an impurity spin in a carbon nanotube double quantum dot.

We make use of spin selection rules to investigate the electron spin system of a carbon nanotube double quantum dot. Measurements of the electron transport as a function of the magnetic field and energy detuning between the quantum dots reveal an intricate pattern of the spin state evolution. We demonstrate that the complete set of measurements can be understood by taking into account the interplay between spin-orbit interaction and a single impurity spin coupled to the double dot. The detection and tunability of this coupling are important for quantum manipulation in carbon nanotubes

Aural toilet (ear cleaning) for chronic suppurative otitis media

BACKGROUND: Chronic suppurative otitis media (CSOM), sometimes referred to as chronic otitis media (COM), is a chronic inflammation and often polymicrobial infection (involving more than one micro-organism) of the middle ear and mastoid cavity, characterised by ear discharge (otorrhoea) through a perforated tympanic membrane. The predominant symptoms of CSOM are ear discharge and hearing loss. Aural toileting is a term describing a number of processes for manually cleaning the ear. Techniques used may include dry mopping (with cotton wool or tissue paper), suction clearance (typically under a microscope) or irrigation (using manual or automated syringing). Dry mopping may be effective in removing mucopurulent discharge. Compared to irrigation or microsuction it is less effective in removing epithelial debris or thick pus. Aural toileting can be used alone or in addition to other treatments for CSOM, such as antibiotics or topical antiseptics. OBJECTIVES: To assess the effects of aural toilet procedures for people with CSOM. SEARCH METHODS: The Cochrane ENT Information Specialist searched the Cochrane ENT Register; Central Register of Controlled Trials (CENTRAL via the Cochrane Register of Studies); Ovid MEDLINE; Ovid Embase; CINAHL; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the search was 16 March 2020. SELECTION CRITERIA: We included randomised controlled trials (RCTs) with at least a one-week follow-up involving people (adults and children) who had chronic ear discharge of unknown cause or CSOM, where the ear discharge had continued for more than two weeks. We included any aural toileting method as the intervention, at any frequency and for any duration. The comparisons were aural toileting compared with a) placebo or no intervention, and b) any other aural toileting method. We analysed trials in which background treatments were used in both arms (e.g. topical antiseptics or topical antibiotics) separately. DATA COLLECTION AND ANALYSIS: We used the standard Cochrane methodological procedures. We used GRADE to assess the certainty of the evidence for each outcome. Our primary outcomes were: resolution of ear discharge or 'dry ear' (whether otoscopically confirmed or not), measured at between one week and up to two weeks, two weeks to up to four weeks, and after four weeks; health-related quality of life using a validated instrument; and ear pain (otalgia) or discomfort or local irritation. Secondary outcomes were hearing, serious complications, and the adverse events of ear bleeding and dizziness/vertigo/balance problems. MAIN RESULTS: We included three studies with a total of 431 participants (465 ears), reporting on two comparisons. Two studies included only children with CSOM in the community (351 participants) and the other study (80 participants) included children and adults with chronic ear discharge for at least six weeks. None of the included studies reported the outcomes of health-related quality of life, ear pain or the adverse event of ear bleeding. Daily aural toileting (dry mopping) versus no treatment Two studies (351 children; 370 ears) compared daily dry mopping with no treatment. Neither study presented results for resolution of ear discharge at between one and up to two weeks or between two to four weeks. For resolution of ear discharge after four weeks, one study reported the results per person. We are very uncertain whether there is a difference at 16 weeks (risk ratio (RR) 1.01, 95% confidence interval (CI) 0.60 to 1.72; 1 study; 217 participants) because the certainty of the evidence is very low. No results were reported for the adverse events of dizziness, vertigo or balance problems. Only one study reported serious complications, but it was not clear which group these patients were from, or whether the complications occurred pre- or post-treatment. One study reported hearing, but the results were presented by treatment outcome rather than by treatment group so it is not possible to determine whether there is a difference between the two groups. Daily aural toileting versus single aural toileting on top of topical ciprofloxacin One study (80 participants; 95 ears) compared daily aural toileting (suction) with administration of topical antibiotic (ciprofloxacin) ear drops in a clinic, to a single aural toileting (suction) episode followed by daily self-administered topical antibiotic drops, in participants of all ages. We are unsure whether there is a difference in resolution of ear discharge at between one and up to two weeks (RR 1.09, 95% CI 0.91 to 1.30; 1 study; 80 participants) because the certainty of the evidence is very low. There were no results reported for resolution of ear discharge at between two to four weeks. The results for resolution of ear discharge after four weeks were presented by ear, not person, and could not be adjusted to by person. One patient in the group with single aural toileting and self administration of topical antibiotic ear drops reported the adverse event of dizziness, which the authors attributed to the use of cold topical ciprofloxacin. It is very uncertain whether there is a difference between the groups (RR 0.33, 95% CI 0.01 to 7.95; 1 study; 80 participants, very low-certainty). No results were reported for the other adverse events of vertigo or balance problems, or for serious complications. The authors only reported qualitatively that there was no difference between the two groups in hearing results (very low-certainty). AUTHORS' CONCLUSIONS: We are very uncertain whether or not treatment with aural toileting is effective in resolving ear discharge in people with CSOM, due to a lack of data and the poor quality of the available evidence. We also remain uncertain about other outcomes, including adverse events, as these were not well reported. Similarly, we are very uncertain whether daily suction clearance, followed by antibiotic ear drops administered at a clinic, is better than a single episode of suction clearance followed by self-administration of topical antibiotic ear drops

Phenological tracking of a seasonal climate window in a recovering tropical island bird species

Constraints on evolutionary adaptation and range shifts mean that phenotypic plasticity, which includes physiological, developmental or behavioural responses to environmental conditions, could be an important mode of adaptation to a changing climate for many species with small insular populations. While there is evidence to suggest adaptive plasticity to climate in some island populations, little is known about this capacity in species that have experienced a severe population bottleneck. In a changing climate, plasticity in the timing of life-history events, such as in breeding phenology, is adaptive if timing is optimised in seasonal environments, although these processes are poorly understood for tropical species. Here, we quantify the effects of climate on the breeding phenology and success of the Mauritius kestrel (Falco punctatus), a tropical raptor whose extinction has been averted by conservation management. We show that the timing of egg-laying is advancing in response to warming, at rates similar to temperate bird populations. Individual females show plasticity to temperature, although there is limited variation among individual responses. We show that advances in breeding phenology are likely to be adaptive, as they track changes in a seasonal climate window of favourable conditions, defined by late winter-early spring temperatures and the onset of the summer rainy season. Our results provide a rare example of a small and bottlenecked insular population that has adjusted to recent climate change through phenotypic plasticity. Furthermore, seasonal climate windows and their dynamics may be widespread mechanisms through which tropical species are impacted by and respond to climate change

Quantifying drivers of supplementary food use by a reintroduced, critically endangered passerine to inform management and habitat restoration

The provision of supplementary food is widely used in the management of endangered species. Typically, food is provided ad libitum and often without a planned exit strategy, which can be costly. The role supplementary food plays within population demography can be challenging to identify and therefore any reduction must be carefully considered to avoid negative impacts. Here we investigate the role supplementary food plays within a reintroduced population of a Critically Endangered passerine species by quantifying its use alongside intrinsic and extrinsic factors. Specifically, we illustrate how the provision of supplementary food could be refined in response to breeding stage and the time of food provisioning and, via habitat restoration, create a long-term exit strategy based on influential plant species. The consumption of supplementary food increases during energetically expensive phases of the breeding cycle, during the morning provision of food and when natural plant resource availability is low. We also show a pattern whereby supplementary food could act as a buffer during periods of low natural resource availability during breeding. Based on these findings short-term management could take a reactive approach; refining supplementary food supply in response to breeding stages of pairs and potentially removing the provision of food in the afternoon. In the long-term key plant species, found to correlate with a decrease in supplementary food consumption, could be incorporated into habitat restoration efforts which could create a continuous natural food supply and contribute to creating a self-sustaining population and a potential exit strategy

Biochemical, Anatomical, and Pharmacological Characterization of Calcitonin-Type Neuropeptides in Starfish: Discovery of an Ancient Role as Muscle Relaxants

Calcitonin (CT) is a peptide hormone released by the thyroid gland that regulates blood Ca2+ levels in mammals. The CT gene is alternatively spliced, with one transcript encoding CT and another transcript encoding the CT-like neuropeptide calcitonin-gene related peptide (α-CGRP), which is a powerful vasodilator. Other CT-related peptides in vertebrates include adrenomedullin, amylin, and intermedin, which also act as smooth muscle relaxants. The evolutionary origin of CT-type peptides has been traced to the bilaterian common ancestor of protostomes and deuterostomes and a CT-like peptide (DH31) has been identified as a diuretic hormone in some insect species. However, little is known about the physiological roles of CT-type peptides in other invertebrates. Here we characterized a CT-type neuropeptide in a deuterostomian invertebrate—the starfish Asterias rubens (Phylum Echinodermata). A CT-type precursor cDNA (ArCTP) was sequenced and the predicted structure of the peptide (ArCT) derived from ArCTP was confirmed using mass spectrometry. The distribution of ArCTP mRNA and the ArCT peptide was investigated using in situ hybridization and immunohistochemistry, respectively, revealing stained cells/processes in the nervous system, digestive system, and muscular organs, including the apical muscle and tube feet. Investigation of the effects of synthetic ArCT on in vitro preparations of the apical muscle and tube feet revealed that it acts as a relaxant, causing dose-dependent reversal of acetylcholine-induced contraction. Furthermore, a muscle relaxant present in whole-animal extracts of another starfish species, Patiria pectinifera, was identified as an ortholog of ArCT and named PpCT. Consistent with the expression pattern of ArCTP in A. rubens, RT-qPCR revealed that in P. pectinifera the PpCT precursor transcript is more abundant in the radial nerve cords than in other tissues/organs analyzed. In conclusion, our findings indicate that the physiological action of CT-related peptides as muscle relaxants in vertebrates may reflect an evolutionarily ancient role of CT-type neuropeptides that can be traced back to the common ancestor of deuterostomes

Assisted extraction of the energy level spacings and lever arms in direct current bias measurements of one-dimensional quantum wires, using an image recognition routine

A multiplexer technique is used to individually measure an array of 256 split gates on a single GaAs/AlGaAs heterostructure. This results in the generation of large volumes of data, which requires the development of automated data analysis routines. An algorithm is developed to find the spacing between discrete energy levels, which form due to transverse confinement from the split gate. The lever arm, which relates split gate voltage to energy, is also found from the measured data. This reduces the time spent on the analysis. Comparison with estimates obtained visually show that the algorithm returns reliable results for subband spacing of split gates measured at 1:4 K. The routine is also used to assess DC bias spectroscopy measurements at lower temperatures (50 mK). This technique is versatile and can be extended to other types of measurements. For example, it is used to extract the magnetic field at which Zeeman-split 1D subbands cross one another.This work was supported by the Engineering and Physical Sciences Research Council grant No. EP/IO14268/1.This is the accepted manuscript. The final version is available from AIP at http://scitation.aip.org/content/aip/journal/jap/117/1/10.1063/1.4905484