Internet addiction in adolescents: prevalence and risk factors

As new media are becoming daily fare, Internet addiction appears as a potential problem in adolescents. From the reported negative consequences, it appears that Internet addiction can have a variety of detrimental outcomes for young people that may require professional intervention. Researchers have now identified a number of activities and personality traits associated with Internet addiction. This study aimed to synthesise previous findings by (i) assessing the prevalence of potential Internet addiction in a large sample of adolescents, and (ii) investigating the interactions between personality traits and the usage of particular Internet applications as risk factors for Internet addiction. A total of 3,105 adolescents in the Netherlands filled out a self-report questionnaire including the Compulsive Internet Use Scale and the Quick Big Five Scale. Results indicate that 3.7% of the sample were classified as potentially being addicted to the Internet. The use of online gaming and social applications (online social networking sites and Twitter) increased the 2 risk for Internet addiction, whereas extraversion and conscientiousness appeared as protective factors in high frequency online gamers. The findings support the inclusion of 'Internet addiction' in the DSM-V. Vulnerability and resilience appear as significant aspects that require consideration in further studies

Liver Iron Contents in Rats after Administration of Certain Iron Compounds

The effect of consumption of certain iron compounds on liver iron deposition was studied in rats, in each case at 4 dietary iron levels ranging from 70 to 206 mg/100 g diet. In one of two series the basic diet was maize porridge meal, and in the other, a semisynthetic 'balanced' diet was fed. The siderogenicity of the iron compounds, when fed with maize porridge meal, was found to be in the following order: ferrous chloride> pulverised steel> pulverised cast iron>ferric chloride>ferric citrate=ferric lactate> ferric oxide. The relatively high siderotic effect of cast iron was reduced considerably when fed together with a semisynthetic 'balanced' diet. It was concluded that the presence of free iron particles in food, as well as the conditions prevailing in the gut as a result of consumption of a predominantly maize diet, are important contributing factors in the development of siderosis in the rat and most probably also in Blacks.S. A fr. Med. J., 48, 505 (1974)

Evolving solitons in bubbly flows

At the end of the sixties, it was shown that pressure waves in a bubbly liquid obey the KdV equation, the nonlinear term coming from convective acceleration and the dispersive term from volume oscillations of the bubbles.\ud For a variableu, proportional to –p, wherep denotes pressure, the appropriate KdV equation can be casted in the formu t –6uu x +u xxx =0. The theory of this equation predicts that, under certain conditions, solitons evolve from an initial profileu(x,0). In particular, it can be shown that the numberN of those solitons can be found from solving the eigenvalue problem xx–u(x,0)=0, with(0)=1 and(0)=0.N is found from counting the zeros of the solution of this equation betweenx=0 andx=Q, say,Q being determined by the shape ofu(x,0). We took as an initial pressure profile a Shockwave, followed by an expansion wave. This can be realised in the laboratory and the problem, formulated above, can be solved exactly.\ud In this contribution the solution is outlined and it is shown from the experimental results that from the said initial disturbance, indeed solitons evolve in the predicated quantity.\u

Kinetic Analysis of Discrete Path Sampling Stationary Point Databases

Analysing stationary point databases to extract phenomenological rate constants can become time-consuming for systems with large potential energy barriers. In the present contribution we analyse several different approaches to this problem. First, we show how the original rate constant prescription within the discrete path sampling approach can be rewritten in terms of committor probabilities. Two alternative formulations are then derived in which the steady-state assumption for intervening minima is removed, providing both a more accurate kinetic analysis, and a measure of whether a two-state description is appropriate. The first approach involves running additional short kinetic Monte Carlo (KMC) trajectories, which are used to calculate waiting times. Here we introduce `leapfrog' moves to second-neighbour minima, which prevent the KMC trajectory oscillating between structures separated by low barriers. In the second approach we successively remove minima from the intervening set, renormalising the branching probabilities and waiting times to preserve the mean first-passage times of interest. Regrouping the local minima appropriately is also shown to speed up the kinetic analysis dramatically at low temperatures. Applications are described where rates are extracted for databases containing tens of thousands of stationary points, with effective barriers that are several hundred times kT.Comment: 28 pages, 1 figure, 4 table

BBMRI-ERIC DIRECTORY USER MANUAL

Short user manual for the BBMRI-ERIC Directory to explain the basic concepts. The manual describes how to navigate the Directory and to search for biobanks or collections

Concussion in sport: what is known and what is new?

The aim of this article was to summarise the latest definition of concussion, signs of concussion, as well as important facts on recovery and graduated return to play, for different age groups. New technologies available to the sports physician are listed.Keywords: concussion, diagnosis, return to play, sign

A Unifying Theory of Biological Function

A new theory that naturalizes biological function is explained and compared with earlier etiological and causal role theories. Etiological theories explain functions from how they are caused over their evolutionary history. Causal role theories analyze how functional mechanisms serve the current capacities of their containing system. The new proposal unifies the key notions of both kinds of theories, but goes beyond them by explaining how functions in an organism can exist as factors with autonomous causal efficacy. The goal-directedness and normativity of functions exist in this strict sense as well. The theory depends on an internal physiological or neural process that mimics an organism’s fitness, and modulates the organism’s variability accordingly. The structure of the internal process can be subdivided into subprocesses that monitor specific functions in an organism. The theory matches well with each intuition on a previously published list of intuited ideas about biological functions, including intuitions that have posed difficulties for other theories

Emergency care research priorities in South Africa

Background: Emergency care research is rarely undertaken in low- and middle-income countries. A manageable ‘road map’ for research in South African (SA) emergency care is needed to address research gaps.Objective: To identify, collate and prioritise research topics from identified knowledge gaps in emergency care in SA.Methods: Seventy-six individuals were invited to participate in a modified Delphi study. Participants were requested to suggest important research topics before rating them. Consensus was achieved when >75% of participants strongly agreed or disagreed. Participants then ranked the agreed statements before selecting the most appropriate methodology relating to study design, funding and collaboration.Results: Three hundred and fifty topics were suggested by 31 participants. Topics were collated into 123 statements before participants rated them. Consensus was achieved for 39 statements. The highest-ranked priority in the prehospital group was to determine which prehospital interventions improve outcomes in critically ill patients. The competence of emergency care providers in performing common lifesaving skills was deemed the most important in clinical emergency care. Implementing and reviewing quality improvement systems scored the highest under general systems and safety management. Only 22 statements achieved consensus regarding study design. The National Department of Health was the preferred funding source, while private organisations and emergency care societies were identified as possible collaborative partners.Conclusion: This study provides expert consensus on priority research areas in emergency care in SA as a guide for emergency care providers to ensure evidence-based care that is relevant to the SA population