Scientists from the University of Utah in the US have calculated that 1.2 million years ago, at a time when our ancestors were spreading through Africa, Europe and Asia, there were probably only around 18,500 individuals capable of breeding (and no more than 26,000). This made them an endangered species with a smaller population than today’s species such as gorillas (approximately 25,000 breeding individuals) and chimpanzees (an estimated 21,000). They remained an endangered species for around one million years. Researchers said that humans and our ancestors have gone through cycles of large population size and also periods perilously close to extinction. The findings were reported online in the Proceedings of the National Academy of Sciences.
?The Force of Gravity
I have emphasised… that the behaviour of bulk spacetime is similar to the behaviour of a macroscopic body of, say, gas and can be usefully described through thermodynamic concepts”: Thanu Padmanabhan, Professor and Dean at the Inter-University Centre for Astronomy and Astrophysics (IUCAA), Pune.
In the same way that pressure exerted by moving molecules of a gas can exert a force on the lid of a container even though it makes no sense to talk of the pressure of each individual molecule, recent papers by T Padmanabhan at IUCAA, Pune, and Erik Verlinde at the Institute for Theoretical Physics have suggested gravity is a property that emerges out of thermodynamic principles acting on the very stuff of the universe. This would go a long way in explaining the puzzle of gravity, which has stood in the way of a unified theory of physics that would reconcile Quantum Mechanics and the General Theory of Relativity.
For much of the past century, attempts to reconcile the two have ended in failure, but scientists were content to live with the incompatibility because the General Theory deals with the very large where effects of gravity count, while Quantum Mechanics deals with the very small where the effects of gravity are negligible. There is, however, one place where the two theories converge, at the heart of a black hole, and in fact recent theoretical advances have come from the study of black holes.
Think of information in the conventional sense as something stored in a book or computer hard disk. The maximum amount of information in a given space would require the densest amount of matter—that is a black hole. It turns out this maximum is proportional to the surface area of the black hole rather than its volume. Naively, this can be understood to mean that information in any 3-dimensional space can be presented on a 2-dimensional surface, much like a hologram.
The new work starts with such a holographic principle and uses this to derive both Newtonian and Einsteinian laws from thermodynamics under appropriate conditions. In particular, this suggests that the search for the graviton, a fundamental particle believed to mediate the force of gravity, is futile.
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Even small dietary reductions in salt could mean fewer heart attacks, strokes and deaths, according to a study conducted by a team from the University of California, San Francisco, Stanford University Medical Center and Columbia University Medical Center. Reducing salt in the American diet by as little as one-half teaspoon (or 3 gm) per day could prevent nearly 100,000 heart attacks and 92,000 deaths each year. Such benefits are on par with the benefits from reductions in smoking and could save the United States about $24 billion in healthcare costs, the researchers say. According to federal government data, the average American man consumes more than 10 gm of salt (4,000 mg sodium) daily—almost double the recommended amount of salt intake per day.
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According to a study at Texas AgriLife Research, mangoes have been found to prevent certain colon and breast cancer cells in the lab. Dr Susanne Talcott, who with her husband Dr Steve Talcott conducted the study, found that “the breast and colon cancer lines underwent apotosis, or programmed cell death [and] that the mango polyphenolics did not harm the normal cells”. They also discovered the mechanism by which cancer wells were checked. This happened because the cell cycle of cancer cells was disrupted. This indicates a possible mechanism for how cancer cells can be prevented or stopped.
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