First principles are calculations that rely on established mathematical laws of nature without additional assumptions or special models.
But when it comes to the early universe, what are those first principles? We're talking really ab initio - "from the beginning" - as in from the beginning of time onward.
In the beginning, the cosmos experienced rapid inflation, electrons and protons floated free from each other, the universe transitioned from complete darkness to light, and enormous stars formed and exploded to start a cascade of events leading to our present-day universe.
Stock price movements are predictable during short windows, according to a paper written by academics in the Tippie College of Business at the University of Iowa.
They write that price movements can be predicted with a better than 50-50 accuracy for anywhere up to one minute after the stock leaves the confines of its bid-ask spread. Probabilities continue to be significant until about five minutes after it leaves the spread. By 30 minutes, the predictability window has closed.
States that have decriminalized marijuana have also seen dramatic increases in children requiring medical intervention, according to research in the Annals of Emergency Medicine ("Association of Unintentional Pediatric Exposures with Decriminalization of Marijuana in the U.S.") which analyzed call volume to U.S. poison centers from January 2005 through December 2011.
And since this was a study of speed dating participants, it's probably true, for speed dating participants.
Insects taste through hair-like structures on the body called sensilla. Sensilla contain receptor nerve cells, each of which is sensitive to a particular substance.
In insects like the honeybee, sensilla are found on the mouthparts, antenna and the tarsi – the end part of the legs. Honeybees weigh information from both front tarsi to decide whether to feed, finds a new study on the ability of honeybees to taste with claws on their forelegs, which reveals details on how this information is processed.
A new study found that the ability to follow another's gaze or look in the direction someone is pointing, two examples of receptive joint attention, is significantly heritable.
Determining such communicative cues are significantly heritable means variation in this ability has a genetic basis, the authors say, which has led them to the vasopressin receptor gene, known for its role in social bonding.
They are looking for insight into the biology of disorders in which receptive joint attention is compromised, such as autism spectrum disorders (ASD), which could lead to new diagnosis and treatment strategies.
In 2005,the Japanese spacecraft Hayabusa revealed that the near-Earth asteroid (25143) Itokawa has a strange peanut shape, leading to questions about why. Now, using ground-based observations, a group has measured the speed at which Itokawa spins and how that spin rate is changing over time and combined these observations with theoretical work on how asteroids radiate heat.
In the MGM musical "Gigi", Maurice Chevalier and Hermione Gingold perform "I Remember It Well", wherein everything they remember contradicts each other.
It's a charming number, and accurate, according to a new Northwestern Medicine study. Our memory, the authors write, takes fragments of the present and inserts them into past memories. Recollections are updated with current information.
Sometimes it's just public relations. We subsidize nicotine patches but regulators are increasingly interested in banning electronic cigarettes.
Such misguided legislation, not backed by sound data, may have consequences for public health, experts say. With smoking blamed for up to six million premature deaths each year, a lot is at stake in the newest push for regulations.
The subject of endocrine disruption is not particularly new, with extensive scientific and regulatory attention to endocrine disrupting chemicals (EDCs) over the last 20 years or so. A common definition, from the World Health Organization/International Programme on Chemical Safety, is:-->
A new paper correlates brain activity with how people make decisions.
Based on these images, the authors suggest that when individuals engage in risky behavior, such as drunk driving or unsafe sex, it's not because their brains' desire systems are too active, but because their self-control systems are not active enough.
Defense lawyers now have a new way to make criminal behavior exculpatory. Unless the judge knows something about the weaknesses of inferring cause and effect based on magnetic resonance imaging (MRI) and read this article about how mainstream media love weak observational studies because they make for catchy headlines.
Most medications prescribed in primary care contain animal derived products.
Are they suitable for vegetarians?
Dietary preferences are common in the general population. Influences such as religion, culture, economic status, environmental concern and personal preferences all play a part in the foods that people choose to consume. Most doctors are unaware that commonly prescribed drugs contain animal products and would be surprised that it matters. But most patients are not aware either and if they have a dietary preference it might impact the medicines they are willing to take also.
Lorena Moscardelli of Statoil North America–Research, Development and Innovation in Austin is not the first to claim evidence to support the existence of a Martian ocean during the late Hesperian–early Amazonian. Viking Orbiter images did that throughout the 1980s and early 1990s.
Others have based their beliefs on alleged paleoshorelines, which has been heavily contested due to large variations in elevation (and some turned out to be of volcanic origin), but Moscardelli uses a new terrestrial, deep-water analogy.
The increasing use of chemical herbicides, both synthetic and organic kinds, is often blamed for the declining plant biodiversity in farms, but it is simplistic to think herbicide exposure is solely to blame.
The science doesn't add up. If herbicides are a key factor in declining diversity, then thriving species would be more tolerant to widely used herbicides than rare or declining species, according to J. Franklin Egan, research ecologist, USDA-Agricultural Research Service. But that isn't the case.
Almost one-third of US adolescents consume high-caffeine energy drinks and the teens who do also report higher rates of alcohol, cigarette, or drug use, according to a paper in the Journal of Addiction Medicine.
The same characteristics that attract young people to consume energy drinks—such as being "sensation-seeking or risk-oriented" — may make them more likely to use other substances as well, suggests the new paper by Yvonne M. Terry-McElrath, MSA, and colleagues of the Institute for Social Research, University of Michigan, Ann Arbor.