Girls moving through adolescence may experience unhealthy levels of weight gain and a new study in The Journal of Pediatrics analyzes the effect of Internet usage, sleep, and alcohol and coffee consumption.
Dr. Catherine Berkey and colleagues from Harvard Medical School, Brigham & Women's Hospital, and Washington University led the Growing Up Today Study (GUTS), which surveyed more than 5000 girls between the ages of 14 and 21 years from all 50 states. They asked the girls to reflect on their weekly habits over the past year and report the following: 1) hours of sleep per night; 2) time spent on the Internet (excluding time for work or school); 3) number of alcoholic beverages consumed; and 4) number of coffee beverages consumed. The girls also reported their height and weight at the beginning and end of the one-year study.
An increasing number of 70 year olds are having good sex and more often, and women in this age group are particularly satisfied with their sex lives, according to a study published today on BMJ.com.
Knowledge about sexual behaviour in older people (70 year olds) is limited and mainly focuses on sexual problems, less is known about "normal" sexual behaviour in this age group.
Nils Beckman and colleagues from the University of Gothenburg in Sweden, studied attitudes to sex in later life among four representative population samples of 70 year olds in Sweden, who they interviewed in 1971-2, 1976-7, 1992-3, and 2000-1. In total, over 1 500 people aged 70 years were interviewed about different aspects of their sex lives including sexual dysfunctions, marital satisfaction and sexual activity.
The effective treatment of many forms of cancer continues to pose a major problem. Many tumors fail to respond to standard forms of chemotherapy or become resistant to the medication.
Scientists at the Helmholtz Centre for Infection Research (HZI) in Braunschweig, the Hannover Medical School (MHH) and Leibniz-Universität (LUH) in Hanover have now discovered a chemical mechanism with which a natural substance - argyrin - destroys tumours.
The basis for this breakthrough was an observation made by the MHH scientist Prof. Nisar Malek: he had been studying the role of a certain protein - a so-called cyclin-kinase inhibitor - in the development of cancer. In the process, Malek noted that mice in which the breakdown of the kinase inhibitor was suppressed by genetic change have a significantly lower risk of suffering from intestinal cancer.
Scientists have recently become interested in the biomechanics of a very unusual activity: skyscraper run-ups.
Competitors in this extreme sport ascend the steps inside the world's tallest buildings, the winners often scaling thousands of steps in just a few minutes. The study of these athletes could shed light on the metabolic profile of athletes and impact on studies of ageing.
"The wide age range of participants, from teenagers to those approaching their centenary, has improved our knowledge of the decline in body performance as we get older," Professor Alberto Minetti from the University of Milan explains. "Industries involved in cardio-fitness could also include the algorithms that we have developed in heart rate monitors, to help athletes maintain their best possible performance throughout races."
Humans often choose partners based on behavioural keys that are displayed during social interactions. The way we behave in different social contexts can reflect personality traits or temperament that may inspire long-term love. Behavioural norms that we perceive as sexually attractive are not culturally or evolutionarily arbitrary.
However, personality-mediated sexual selection is not just the privilege of mankind. László Garamszegiand colleagues at the University of Antwerp and at Eötvös University, Budapest used bird song as a model to investigate whether behavioural traits involved in sexual advertisement can serve as good indicators of personality in wild animals.
A new mathematical model developed by University of Michigan atmospheric and planetary scientist Nilton Renno says that dust devils, water spouts, tornadoes, hurricanes and cyclones are all born of the same mechanism and will intensify as climate change warms the Earth's surface.
Renno hopes the new equation will allow scientists to more accurately calculate the maximum expected intensity of a spiraling storm based on the depth of the troposphere (the lowest layer of Earth's atmosphere) and the temperature and humidity of the air in the storm's path.
This equation improves upon current methods, Renno says, because it takes into account the energy feeding the storm system and the full measure of friction slowing it down. Current thermodynamic models make assumptions about these variables, rather than include actual quantities.