Science
Why Do Women Score Low in Physics?
In a new synthesis of past work, researchers found that women consistently score lower than men on common assessments of conceptual understanding of physics. However, when examining the factors that may account for these differences (such as student background and test-taking strategies), no clear pattern emerged. Thus, despite previous claims that the causes of this gender gap have been pinpointed, the problem remains unsolved and poorly understood. This has critical importance for science education reform.
Many changes have been made in college science instruction in the past decades. Numerous classrooms have shifted from a traditional lecture presentation to more interactive formats that aim to engage students in building their own knowledge. Physics has been a forerunner of this movement.
Several studies had reported that women's scores on these tests are typically lower than men's. The authors combined results from 26 previous studies of several common physics concept inventories, covering 12 different institutions. They found that women almost always score lower than men on these tests (12% on average for tests about force and motion), both before instruction, and at the end of the course.
The authors cross-checked the results from studies investigating the potential impact of student background, their beliefs about physics, the teaching method used, their ingrained stereotypes about women's abilities, and the wording of test questions. Some demonstrated that one or more of these elements had a significant influence, but most were contradicted in other studies
While the gender gap on physics concept inventories remains an unsolved problem, the researchers suggest some take-home messages for instructors. One is that the use of interactive teaching techniques can improve student understanding for both genders. Another is simply to recognize that there is a gender gap on conceptual assessments and exams, and that addressing this gap will require creativity on the part of the instructor.
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Kids Who Sleep More, May Eat Less
It seems everyone is looking for a culprit when it comes to childhood obesity: fast food, sugary drinks, super-sized everything. But it turns out part of the blame may lie with the simple matter of turning out the lights and rolling into bed, according to a study by Chantelle Hart, associate professor of public health at Temple University.
The study involved 37 children, ages 8 to 11; 27 percent of whom were overweight or obese.
For the first week of the study, children were asked to sleep their typical amount. Next, during the second week, the group was randomized to either reduce or lengthen their sleep time; participants completed the opposite sleep schedule during the third and final week of the study.
The results were conclusive: During the week that the children increased their sleep, they reported consuming an average of 134 fewer calories per day, weighed a half pound less, and had lower fasting levels of leptin, a hunger-regulating hormone that is also highly correlated with the amount of adipose tissue, when compared to the week of decreased sleep.
Hart is working on a study funded by the National Heart Lung and Blood Institute of the NIH using a brief behavioral intervention to get kids to increase their sleep to determine if there are significant changes in eating, activity behaviors and weight status.
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Computer Model Anticipates Crime Hot Spots
A unique collaboration between Robert Nash Parker, professor of sociology at University of California, Riverside and the Indio Police Chief Richard P. Twiss has produced a computer model that predicts, by census block group, where burglaries are likely to occur.
Parker began working with the Indio Police Department in 2010 to determine if a computer model could predict by census block group -- the smallest geographic unit the Census Bureau uses -- where burglaries were most likely to occur.
Using crime data and truancy records -- truants account for a significant number of daytime burglaries -- Parker discovered patterns of crime over time and space. Most computer models account for changes over time or a variety of places, but not both.
Parker and Indio police reviewed 10 years of data and discovered that as truancy arrests shifted geographically in the city, there was a correlation between daytime burglaries and truancy.
Police launched several outreach programs as a result, including a burglary and truancy prevention task force, community safety fairs and meetings, media campaigns, and stronger partnership efforts with local business owners and others.
The result is an 8 percent decline in thefts in the first nine months of 2013.
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Civilizations Rise and Fall On the Quality of Their Soil
Great civilisations have fallen because they failed to prevent the degradation of the soils on which they were founded. The modern world could suffer the same fate.
This is according to Professor Mary Scholes, Professor of Environmental Sciences at Wits University and Dr Bob Scholes, a systems ecologist at the Council for Scientific and Industrial Research. They have recently published a paper which describes how the productivity of many lands has been dramatically reduced as a result of soil erosion, accumulation of salinity, and nutrient depletion.
Although improved technology -- including the unsustainably high use of fertilisers, irrigation, and ploughing -- provides a false sense of security, about 1% of global land area is degraded every year. In Africa, where much of the future growth in agriculture must take place, erosion has reduced yields by 8% and nutrient depletion is widespread.
However, it is not possible to feed the current and future world population with a dogmatically "organic" approach to global agriculture.
To achieve lasting food and environmental security, we need an agricultural soil ecosystem that more closely approximates the close and efficient cycling in natural ecosystems, and that also benefits from the yield increases made possible by biotechnology and inorganic fertilisers.
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