Narrow Results

Slugs are significant pests in agriculture (as well as a nuisance to gardeners), and it is therefore important to understand their population dynamics for the construction of efficient and effective control measures. Differential equation models of slug populations require the inclusion of large (variable) temporal delays, and strong seasonal forcing results in a non-autonomous system. This renders such models open to only a limited amount of rigorous analysis. In this paper, we derive a novel batch model based purely upon the quantity of eggs produced at different times of the year. This model is open to considerable reduction; from the resulting two variable discrete-time system it is possible to reconstruct the dynamics of the full population across the year and give conditions for extinction or global stability and persistence. Furthermore, the steady state temporal population distribution displays qualitatively different behavior with only small changes in the survival probability of slugs. The model demonstrates how small variations in the favorability of different years may result in widely different slug population fluctuations between consecutive years, and is in good agreement with field data.

In medical research, the results from seasonality analyses provide valuable information that eventually can help to clarify the etiology of poorly understood diseases. We present a Bayesian procedure for the analysis of seasonal variation in medical data. The method is a Bayesian version of a frequentist test that performs very well. Statistical seasonality analyses of medical data often involve a short time series, 12 observations with small amplitude and small sample size. Among the specialized procedures already developed for such analyses, only one is Bayesian; the method we present in this paper appears to be the second such Bayesian procedure. Easy to understand and apply, the method is versatile because it can be used to analyze different types of seasonal variation. We illustrate the procedure’s application with two examples of real data.

Based on temperature and rainfall recorded at 34 meteorological stations in Bangladesh during 1989–2018, the trends of yearly average maximum and minimum temperatures have been found to be increasing at the rates of 0.025^∘C and 0.018^∘C per year. Analysis of seasonal average maximum temperature showed increasing trend for all seasons except the late autumn season. The increasing trend was particularly significant for summer, rainy and autumn seasons. Seasonal average minimum temperature data also showed increasing trends for all seasons. The trend of yearly average rainfall has been found to be decreasing at a rate of 0.014mm per year in the same period; especially, for most of the meteorological stations the rainfall demonstrates an increasing trend for rainy season and a decreasing trend in the winter season. It means that in Bangladesh dry periods became drier and wet periods became wetter.

An updated version of the Regional Acid Deposition Model (RADM) driven by meteorological fields derived from the Chinese Regional Climate Model (CRegCM) is used to simulate seasonal variation of tropospheric ozone over eastern China. The results show that:

Peak O₃ concentration area moves from southern to northern China in response to the shifting of solar perpendicular incidence point from south to north.

In eastern China, the highest O₃ month-average concentration occurs in July, the lowest in January, and intermediate values in April and October. The pattern mainly depends on solar radiation, the O₃ concentration precursors of NO_x and NMHC, and the ratio of NMHC/NO_x.

Diurnal variations of O₃ over eastern China are well defined. O₃ concentration increases with the rising sun, reaching its maximum at noon and then falling off. The range of variation is highest in summer (40 × 10⁻⁹ in volume fraction) and lowest in winter (20 × 10⁻⁹ in volume fraction).

Diurnal variations of O₃ over western China are not as clear. The range of variation is less than 10 × 10⁻⁹ in volume fraction.

NO_x concentration increases as its emission increases. In January, surface O₃ decreases as NO_x increases. In July, O₃ generally increases over the country. In April and October, O₃ decreases in northeastern China, northern China and Sichuan province but increases in other areas.

Major lower limb amputation is the most dreadful complication of diabetic foot. A review on Hong Kong Chinese diabetics with ulcerated feet has identified ulcer depth, peripheral vascular insufficiency, old age and hypoalbuminemia to be factors associated with major amputation. An infected ulcer, neuropathy, anaemia and low lymphocyte count are frequently observed in this group of amputees. Amputation has a seasonal variation and is more commonly performed in summer. Establishing a dedicated clinic for this group of patients can lead to a dramatic decrease in amputation. Input from different disciplines is of vital importance to its success.