When an epidemic breaks out, many health, economic, social, and political problems arise that require a prompt and effective solution. It would be useful to obtain all information about the virus, including epidemiological ones, as soon as possible. In a previous study of our group, the analysis of the positive-alive was proposed to estimate the epidemic duration. It was stated that every epidemic ends when the number of positive-alive (=infected-healed-dead) glides toward zero. In fact, if with the contagion everyone can enter the epidemic phenomenon, only by healing or dying can they get out of it. In this work, a different biomathematical model is proposed. A necessary condition for the epidemic to be resolved is that the mortality reaches the asymptotic value, from there, remains stable. At that time, the number of positive-alive must also be close to zero. This model seems to allow us to interpret the entire development of the epidemic and highlight its phases. It is also more appropriate than the previous one, especially when the spread of the infection is so rapid that the increase in live positives is staggering.

On 11 March 2020, coronavirus disease 2019 (COVID-19) was declared a pandemic by the World Health Organization (WHO). As of 12.44 GMT on 15 January 2021, it has produced 93,640,296 cases and 2,004,984 deaths. The use of mathematical modelling was applied in Italy, Spain, and UK to help in the prediction of this pandemic. We used equations from general and reduced logistic models to describe the epidemic development phenomenon and the trend over time. We extracted this information from the Italian Ministry of Health, the Spanish Ministry of Health, Consumer Affairs, and Social Welfare, and the UK Statistics Authority from 3 February to 30 April 2020. We estimated that, from the seriousness of the phenomenon, the consequent pathology, and the lethal outcomes, the COVID-19 trend relate to the same classic laws that govern epidemics and their evolution. The curve d(t) helps to obtain information on the duration of the epidemic phenomenon, as its evolution is related to the efficiency and timeliness of the system, control, diagnosis, and treatment. In fact, the analysis of this curve, after acquiring the data of the first three weeks, also favors the advantage to formulate forecast hypotheses on the progress of the epidemic.

Introduction: Body mass index (BMI) provides little information on body composition. For example, two people with the same BMI might have different body compositions. In this sense, the development of a new BMI able to provide body composition information is of clinical and scientific interest. The aim of the study was to suggest a new modified BMI formula.Material and methods: A total of 108 subject, females 56 and males 52, 0-73 years old, in various physiopathological conditions were evaluated. Data were collected and processed by a program that through anthropometric measurements calculates classic BMI, volume, surface, V/S (that we can defined like a body-thickness “pseudospessore”) and the new BMI-BFMNU.Results: The basic formula (BMI =Body Mass [kg]/Height [m2]) uses the height squared as the value of the body surface, although this is only an approximation of the real surface, whereas using the real surface instead, the new BMI reflects better the ratio between the body volume and its surface. The ratio called "pseudospessore" is already used in literature from the BFMNU (Italian acronym refereed to Biologia e Fisiologia Modellistica della Nutrizione Umana) method and has been shown to be related to the amount of fat.Conclusions: Using the BMI-BFMNU, it is possible to obtain an indication of the body structure related to the amount of fat. The consequence is that the obtained numerical values do not coincide with the traditional BMI’s values and will refer to different normal ranges. For instance, a person may be in the range of normal weight for both BMI measurements, but only the BMI-BFMNU detects whether a person has a higher or lower fat content considering the individual’s category. This study opens up to new possible future developments on the application of the new BMI that will allow a more accurate assessment and classification of patients.

the correlation between food energy and body mass is not significant, being a critical point about the diets designed on an energy basis. However, the body mass of an individual is determined by mass balance, regulated by corresponding metabolic rate, calculated by the BFMNU method, thanks to which the macronutrients in the diet are absorbed, redistributed and eliminated. A significant correlation, although not straight, is demonstrated between Δ% of food energy, supplied after processing through the dietary BFMNU method, and the Δ% of body mass, obtained following the dietetic path.

Nowadays, obesity is a pandemic, and some people seek slimming diets to guarantee their health and quality of life. However, the cult of the healthy body has been an ongoing concern since the beginning of time. Irrespective of the century to which they belong, these cults reflect no empirical knowledge about physiology, nutrients or kilocalories, with some of them being quantitative diets in contrast to qualitative diets, or even simple food recommendations. On the other hand, some of these treatments might have led to the death of a patient, meaning that it is important for people seeking to lose weight to be followed by a nutrition professional until the individual reaches a desirable body weight. In this article, we highlight that each century and each decade have devised different treatments with the aim of improving health, but it will be science and history that will judge whether the results of these treatments have been adequate.