Summary
Background
While the prevalence of asthma in children is decreasing or remaining the same, time trends in the prevalence of rhinitis in children are not known. Understanding sensitisation ...trends may help inform about trends in asthma and rhinitis prevalence.
Objective
To assess time trends of wheeze, rhinitis and aero‐allergen sensitisation prevalence at 10 years of age, we compared two birth cohorts established 12 years apart. To gain insight into differences in disease prevalence, we assessed association of family history, early life exposures and sensitisation with wheeze and rhinitis in each cohort.
Methods
The IoW (Isle of Wight) and FAIR (Food Allergy and Intolerance Research) unselected birth cohorts were established in 1989 and 2001 respectively in IoW. Identical ISAAC questionnaire and skin prick test data were collected and compared at 10 years of age.
Results
Over the 12‐year period from 2001 to 2012, prevalence of lifetime wheeze, current wheeze and those ever treated for asthma decreased by 15.9% (45.5 vs. 29.6, P < 0.001), 3.9% (18.9 vs. 15, P = 0.020) and 8.2% (31.7 vs. 23.5, P = 0.001), respectively. Conversely, current rhinitis and lifetime rhinitis prevalence increased by 5.5% (22.6 vs. 28.1, P = 0.004) and 13% (18.6 vs. 31.7, P < 0.001), respectively. Atopic status remained stable; however, house dust mite (HDM) sensitisation decreased by 5.6% (19.2 vs. 13.6, P = 0.004) and grass sensitisation increased by 3.5% (12.9 vs. 16.4, P = 0.054). Male sex, parental history of asthma and HDM sensitisation were significantly associated with lifetime wheeze in both cohorts, while maternal smoking during pregnancy was a significant risk factor only in the earlier IoW cohort. Parental history of rhinitis and grass sensitisation was significantly associated with lifetime rhinitis in both cohorts, while HDM sensitisation was significant only for the IoW cohort.
Conclusion
Contrasting changes were noted with falling wheeze and HDM sensitisation but rising rhinitis and grass sensitisation prevalence. Changing prevalence of aero‐allergen sensitisations may explain the different time trends observed in these cohorts.
Millisecond pulsars (MSPs) are a growing class of gamma-ray emitters. Pulsed gamma-ray signals have been detected from more than 40 MSPs with the Fermi Large Area Telescope (LAT). The wider radio ...beams and more compact magnetospheres of MSPs enable studies of emission geometries over a broader range of phase space than non-recycled radio-loud gamma-ray pulsars. We have modeled the gamma-ray light curves of 40 LAT-detected MSPs using geometric emission models assuming a vacuum retarded-dipole magnetic field. We modeled the radio profiles using a single-altitude hollow-cone beam, with a core component when indicated by polarimetry; however, for MSPs with gamma-ray and radio light curve peaks occurring at nearly the same rotational phase, we assume that the radio emission is co-located with the gamma rays and caustic in nature. The best-fit parameters and confidence intervals are determined using a maximum likelihood technique. We divide the light curves into three model classes, with gamma-ray peaks trailing (Class I), aligned (Class II), or leading (Class III) the radio peaks. Outer gap and slot gap (two-pole caustic) models best fit roughly equal numbers of Class I and II, while Class III are exclusively fit with pair-starved polar cap models. Distinguishing between the model classes based on typical derived parameters is difficult. We explore the evolution of the magnetic inclination angle with period and spin-down power, finding possible correlations. While the presence of significant off-peak emission can often be used as a discriminator between outer gap and slot gap models, a hybrid model may be needed.
A prevalence of political violence and political assassinations characterised post-1994 South Africa. These politically motivated killings appeared to be dominant in the controversial KwaZulu-Natal ...(KZN) province. Political killings in South Africa started as a form of inter-party warfare, especially during the transition to democracy, when the two rivals, the African National Congress (ANC) and the Inkatha Freedom Party (IFP), fought each other for some areas of Gauteng and KwaZulu-Natal provinces. However, following the dominance of the ANC in the KZN Province, members of the ruling party fought each other for positions in government and political party structures. Considering this, the article analyses the crisis of factionalism by examining the ANC's intra-party tensions and targeted killings, and how this poses a risk to human security in KZN. Methodologically, the article employs a qualitative literature assessment and content analysis is used to delve into the impact of intra-party tensions and targeted killings on human security in the KZN province.
In quest for curbing the crisis of factionalism in the ruling ANC, the article recommends that the ANC needs to re-visit its leadership selection as these killings have seemingly happened during leadership selection, which leads to ruthless competition of positions in government and party structures. Members of the ruling party need to identify themselves as one, as opposed to belonging to different factional groups within the party. Failure by the ruling party to address divisions within the organisation shall result in more fatal killings resulting from competition for positions and resources.
Terzan 5 is the only Galactic globular cluster that has plausibly been detected at very high energies by the High Energy Stereoscopic System. It has an unexpectedly asymmetric very high energy ...morphology that is offset from the cluster center, in addition to a large-scale, offset radio structure and compact diffuse X-ray emission associated with this cluster. We present new data from the Fermi Large Area Telescope on this source. We model the updated broadband spectral energy distribution, attributing this to cumulative pulsed emission from a population of embedded millisecond pulsars, as well as unpulsed emission from the interaction of their leptonic winds with the ambient magnetic and soft-photon fields. In particular, our model invokes unpulsed synchrotron and inverse Compton components to model the radio and TeV data and cumulative pulsed curvature radiation to fit the Fermi data, and it explains the hard Chandra X-ray spectrum via a "new" cumulative synchrotron component from electron-positron pairs within the pulsar magnetospheres that has not been implemented before. We find reasonable spectral fits for plausible model parameters. We also derive constraints on the millisecond pulsar luminosity function using the diffuse X-ray data and the Chandra sensitivity. Future higher-quality spectral and spatial data will help discriminate between competing scenarios (such as dark matter annihilation, white dwarf winds, or hadronic interactions) proposed for the broadband emission, as well as constraining degenerate model parameters.
ABSTRACT
The next era of ground-based Cherenkov telescope development will see a great increase in both quantity and quality of γ-ray morphological data. This initiated the development of a ...spatiotemporal leptonic transport code to model pulsar wind nebulae. We present results from this code that predicts the evolution of the leptonic particle spectrum and radiation at different radii in a spherically symmetric source. We simultaneously fit the overall broad-band spectral energy distribution, the surface brightness profile, and the X-ray photon index versus radius for PWN 3C 58, PWN G21.5 − 0.9, and PWN G0.9 + 0.1. Such concurrent fitting of disparate data sets is non-trivial and we thus investigate the utility of different goodness-of-fit statistics, specifically the traditional χ2 test statistic and a newly developed scaled-flux-normalized test statistic to obtain best-fitting parameters. We find reasonable fits to the spatial and spectral data of all three sources, but note some remaining degeneracies that will have to be broken by future observations.
The development of reliable strategic traffic models relies on comprehensive and accurate data, but traditional survey methods are time-consuming and expensive. Manual surveys often yield small ...samples that require estimated expansion factors to enable the data to represent the population. Modellers have turned to new data sourced from various electronic devices to improve the reliability of the data. Automatic Number Plate Recognition (ANPR) data is one such data source that can be used to extract travel time, speed and partial origin-destination (OD) information. This study assesses ANPR data in terms of its comprehensiveness and accuracy, and shows how it can be used for the validation of strategic traffic models. Data was obtained from the Gauteng freeway system’s Open Road Tolling (ORT) gantries for a period of several months. A new methodology is developed to process traffic model outputs such that they are directly comparable to the partial origin-destination outputs derived from the ANPR data. It is shown that comparing the model distribution against observed ANPR data highlights potential trip distribution issues that are not detected using standard model validation techniques.
ABSTRACT
The predicted nature of the candidate redback pulsar 3FGL J2039.6–5618 was recently confirmed by the discovery of γ-ray millisecond pulsations (Clark et al., hereafter Paper I), which ...identify this γ-ray source as PSR J2039–5617. We observed this object with the Parkes radio telescope in 2016 and 2019. We detect radio pulsations at 1.4 and 3.1 GHz, at the 2.6 ms period discovered in γ-rays, and also at 0.7 GHz in one 2015 archival observation. In all bands, the radio pulse profile is characterized by a single relatively broad peak which leads the main γ-ray peak. At 1.4 GHz, we found clear evidence of eclipses of the radio signal for about half of the orbit, a characteristic phenomenon in redback systems, which we associate with the presence of intra-binary gas. From the dispersion measure of 24.57 ± 0.03 pc cm−3, we derive a pulsar distance of 0.9 ± 0.2 or 1.7 ± 0.7 kpc, depending on the assumed Galactic electron density model. The modelling of the radio and γ-ray light curves leads to an independent determination of the orbital inclination, and to a determination of the pulsar mass, qualitatively consistent to the results in Paper I.
This paper compares the performance of three competing corridors serving landlocked SADC countries (Beira, Dar es Salaam, and Durban) based on total economic cost from the perspective of ...transporters, retailers, and manufacturers. The motivation for the research is the paradox that, while Beira is closest to the hinterland served by these corridors, it attracts the least cargo. Historical research compares corridors in terms of both direct costs and time delays, but without translating time delays and variability in time delays into the economic costs experienced by corridor users. Unpredictable time delays reduce the competitiveness of cargo owners forming part of global just-in-time value chains. Our novel TEC model includes direct costs and the cost impact of delays and variability in delays and quantifies the relative contributions of ports, border posts, and road travel. The Port’s efficiency proved to be the biggest differentiator between these corridors, followed by border posts and road links. We found that while the Beira corridor has the lowest cost if only average travel time is considered, the Durban corridor proves to be the most competitive when variability in time delays is also considered, explaining why Durban enjoys the largest share of cargo transported to the landlocked hinterland.
Prevalence and incidence of food hypersensitivity (FHS) and its trends in early childhood are unclear.
A birth cohort born on the Isle of Wight (UK) between 2001 and 2002 was followed-up ...prospectively. Children were clinically examined and skin prick tested at set times and invited for food challenges when indicated.
Nine hundred and sixty-nine children were recruited and 92.9%, 88.5% and 91.9% of them respectively were assessed at 1, 2 and 3 years of age. Prevalence of sensitization to foods was 2.2%, 3.8% and 4.5% respectively at these ages. Cumulatively, 5.3% 95% confidence interval (CI): 3.9-7.1 children were sensitized to a food. Using open food challenge and a good clinical history, the cumulative incidence of FHS was 6.0% (58/969, 95% CI: 4.6-7.7). Based on double-blinded, placebo-controlled, food challenge (DBPCFC) and a good clinical history, the cumulative incidence was 5.0% (48/969, 95% CI: 3.7-6.5). There is no evidence to suggest that the incidence of FHS has increased, comparing these results with previous studies. Overall, 33.7% of parents reported a food-related problem and of these, 16.1% were diagnosed with FHS by open challenge and history and 12.9% by DBPCFC and history. Main foods implicated were milk, egg and peanut.
By the age of 3 years, 5-6% of children suffer from FHS based on food challenges and a good clinical history. There were large discrepancies between reported and diagnosed FHS. Comparing our data with a study performed in the USA more than 20 years ago, there were no significant differences in the cumulative incidence of FHS.
In 2014, the European Academy of Allergy and Clinical Immunology (EAACI) published the first systematic review that summarized the prevalence of food allergy (FA) and food sensitization in Europe for ...studies published 2000–2012. However, only summary estimates for tree nut allergy (TNA) were feasible in that work. In the current update of that systematic review, we summarized the prevalence of tree nut allergy/sensitization to individual tree nuts. Six databases were searched for relevant papers published 2012–2021 and 17 eligible studies were added to the 15 studies already identified between 2000 and 2012, giving a total of 32 studies. Of the investigated tree nuts, meta‐analysis was possible for hazelnut, walnut, almond, and in few cases, for cashew, and Brazil nut. The lifetime self‐reported prevalence was 0.8% (95% CI 0.5–1.1) for hazelnut and 0.4% (0.2–0.9) for walnut. The point self‐reported prevalence was 4.0% (2.9–5.2) for hazelnut, 3.4% (2.0–4.9) for Brazil nut, 2.0% (1.1–2.9) for almond, and 1.8% (1.1–2.5) for walnut. Point prevalence of food challenge‐confirmed TNA was 0.04% (0.0–0.1) for hazelnut and 0.02% (0.01–0.1) for walnut. Due to paucity of data, we could not identify any meaningful and consistent differences across age groups and European regions.
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