A study shows how pests are moving north…


cricket

Hundreds of crop pests are advancing away from the tropics at a rate of nearly two miles a year, research has shown.

The mostly likely explanation for the trend is said to be climate change as rising temperatures make new habitats more inviting.

Pest invasions driven by global warming have serious implications for agriculture and food security, according to scientists.

Already, between 10% and 16% of global crop production is lost to pests such as fungi, bacteria, viruses, insects and worms.

Losses caused by fungi and fungi-like micro-organisms alone amount to enough to feed 8.5% of the global population.

Agricultural pests are mainly spread by being carried on transported farm products. But the second most important factor in disseminating pests is weather.

To investigate the likely effect of climate change, British scientists studied data on the distribution of 612 crop pests collected over the past 50 years. They found an average shift towards the north and south poles of around 1.7 miles (2.7km) per year.

Pests whose traditional homes were warmer regions near the equator were branching out to new locations they would have previously found too cold.

Dan Bebber, from University of Exeter, who led the research published in the journal Nature Climate Change, said: “If crop pests continue to march polewards as the Earth warms, the combined effects of a growing world population and the increased loss of crops to pests will pose a serious threat to global food security.”

One example of a serious weather-sensitive pest was the mountain pine beetle, Denroctonus ponderosae. Warmer weather had driven the beetle northward to destroy large areas of pine forest in the US Pacific north-west.

Another was rice blast fungus, a devastating pest affecting more than 80 countries which was now attacking wheat. Considered a new disease, “wheat blast” is having a severe impact in Brazil and there are fears of it spreading further north to the US.

The scientists wrote: “Observed changes in pest distributions accord with observations of wild species, direct responses of pests to warming, and with expectations for expanding pest ranges under climate change.”

Co-author Professor Sarah Gurr, also from University of Exeter, said: “Renewed efforts are required to monitor the spread of crop pests and to control their movement from region to region if we are to halt the relentless destruction of crops across the world in the face of climate change.”

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Underwater astonishments


http://ted.com/talks/view/id/206

David Gallo shows jaw-dropping footage of amazing sea creatures, including a color-shifting cuttlefish, a perfectly camouflaged octopus, and a Times Square’s worth of neon light displays from fish who live in the blackest depths of the ocean.

A pioneer in ocean exploration, David Gallo is an enthusiastic ambassador between the sea and those of us on dry land. He explains that “today we’ve only explored about 3 percent of what’s out there in the ocean. Already we’ve found the world’s highest mountains, the world’s deepest valleys, underwater lakes, underwater waterfalls … . There’s still 97 percent, and either that 97 percent is empty or just full of surprises.”

David Gallo works to push the bounds of oceanic discovery. Active in undersea exploration (sometimes in partnership with legendary Titanic-hunter Robert Ballard), he was one of the first oceanographers to use a combination of manned submersibles and robots to map the ocean world with unprecedented clarity and detail.

On reading the Koran


http://ted.com/talks/view/id/1045

Lesley Hazleton sat down one day to read the Koran. And what she found — as a non-Muslim, a self-identified “tourist” in the Islamic holy book — wasn’t what she expected. With serious scholarship and warm humor, Hazleton shares the grace, flexibility and mystery she found, in this myth-debunking talk.

Le possibili conseguenze di linee d’azione alternative


Regarding the opus of Sir Isaac Newton’s legacy, this enormous corpus of Newton’s documents, papers, manuscripts, including his correspondence, which have survived reveals to us a person with serious qualities of mind, physique, and personality extraordinarily favorable for the making of a great scientist: tremendous powers of concentration, ability to stand long periods of intense mental exertion (some of his contemporaries had affirmed that he was able to concentrate in a problem about 17 hours of mental exercise without a break), and objectivity uncomplicated by any frivolous interests.

When Sir Isaac Newton came to maturity, circumstances were auspiciously combined to make possible major changes in ways of thought and endeavor on human beings. The uniqueness of Newton’s achievement could be said to lie in his exploitation of these unusual circumstances. He alone among his gifted contemporaries fully recognized the implications of recent scientific discoveries. With these as a point of departure, he developed a unified mathematical interpretation of the cosmos, in the expounding of which he demonstrated method and direction for future elaboration. In shifting the emphasis from “quality” to “quantity,” from pursuit of answers to the question “Why?” to focus upon “What?” and “How?,” he effectively prepared the way for the age of technology and modern science.

Masses…


As physicists know, electrons, W and Z particles have masses, but neutrinos and photons do not. I wonder somehow that it could be for some reason that neutrinos, and even photons do have masses so small which they have escaped any sort of detection so far. Though, I think these masses if they do exist would be quite different from the masses of electrons and W and Z particles, that is how not what would or should be expected if the symmetry among these particles were so manifest in nature.

Social determinants


Since we are all now in the same global boat—inhabitants in the same global village—, it is essential for us to understand quite deeply our history as humanity struggling in this planet. Seeking unity of humankind—our relavant relationships with our neighbors and all peoples alike—, we must work in the noble task of comprehend the genesis and evolution of the dominant ideas of the modern world.

On the other hand, I do believe that it is indeed very demostrable that all thinking and all action are compromised by ignorance of what has gone before. Most of us love to believe that we live in a kind of timeless innocence, until something not good or ugly or, worst, lethal, happens to us. Then, I assume and believe these three social determinants are the guideposts or guiding principles in our age: (1) democracy—the search for the goverment from and through the people, (2) equality before the law—we’re all human beings, (3) the unity of the peoples of the world—e pluribus unum.

In peri nomen et verbum


Praemittit autem huic operi Philosophus prooemium, in quo sigillatim exponit ea, quae in hoc libro sunt sunt tractanda. Et quia omnis scientia praemittit ea, quae de principiis sunt; ideo oportet intendenti tractare de enunciatione praemittere de partibus eius.

Unde dicit; Primum oportet constituere, idest definire quid sit nomen et quid sit verbum. In greaco habetur, Primum oportet poni et idem significat. Quia enim demostrationes definitiones praesupponunt, ex quibus concludunt, merito dicuntur positiones. Et ideo praemittuntur hic solae defiitiones eorum, de quibus agendum est: quia ex definitionibus alia cognoscuntur.

Work, work, work…


Working at the Harvard College Observatory at the turn of the 20th Century, Henrietta Leavitt developed the information about Cepheid stars that would make Edwin Hubble’s great discoveries possible. Noticing that these stars varied in brightness at consistent rate that they could be used to measure stellar distances. Applying this yardstick herself, Leavitt showed in 1912 that such variable stars had to be far outside our home galaxy.

She had become especially expert in the characteristics of these variable stars, whose luminosity dims and flares up in cycles, and eventually cataloged about twenty four hundred of them. Most important for Edwin Hubble’s research, she was very able to time the cycles of the Cepheids, By showing that the length of their cycles of luminosity varies in close relation to their brightness, Leavitt provided astronomers with a hitherto unknown celestial yardstick, a method of measuring the distance of stellar objects. If a nearby Cepheid with a certain cycle has a certain degree of luminosity, a remote Cepheid with the same cycle should have the same luminosity. The degree of its relative dimness, from our point of view on Earth, shows how far away it is.

As you can imagine, in this age when very few women were given opportunities in science, these women of the Harvard College Observatory were restricted to classifying celestial phenomena in photographic plates taken by male astronomers. It’s remarkable to notice that in this group of women were to seminal and original thinkers, such as Henrietta Leavitt and Antonia C. Maury. The latter classified stars by the width of the lines they produced on a spectrograph. All of these helped others to nail down the exact dimensions of the Milky Way.

Betelgeuse


Betelgeuse — the second brightest star in the constellation of Orion (the Hunter) — is a red supergiant, one of the biggest stars known, and almost 1000 times larger than our Sun. It is also one of the most luminous stars known, emitting more light than 100 000 Suns.

Betelgeuse is the 12th brightest star in the sky. It is called Alpha Orionis even though it is fainter than Beta Orionis (Rigel). Other names; Betelguex. Betelgeuze, Beteiguex, Al Mankib, Alpha Orionis,  HR 2061,  HD 39801.

Such extreme properties foretell the demise of a short-lived stellar king. With an age of only a few million years, Betelgeuse is already nearing the end of its life and is soon doomed to explode as a supernova. When it does, the supernova should be seen easily from Earth, even in broad daylight.

Pinned prominently on Orion’s shoulder, the bright red star Betelgeuse hardly seems like a wallflower. But a new study suggests the giant star has been shrinking for more than a decade.

Betelgeuse is nearing the end of its life as a red supergiant. The bright, bloated star is 15 to 20 times more massive than the sun. If it were placed at the centre of the solar system, the star would extend out to the orbit of Jupiter.

But the star’s reach seems to be waning. New observations indicate the giant star has shrunk by more than 15 per cent since 1993. This could be a sign of a long-term oscillation in its size or the star’s first death knells. Or it may just be an artefact of the star’s bumpy surface, which may appear to change in size as the star rotates.

Betelgeuse is enshrouded by vast clouds of gas and dust, so measuring its size is difficult. To cut through this cocoon, astronomers used a set of telescopes that are sensitive to a particular wavelength of the star’s infrared light.

Over a span of 15 years, the star’s diameter seems to have declined from 11.2 to 9.6 AU (1 AU, or astronomical unit, is the distance from the Earth to the sun).

The cause for this reduction is unknown, as it is unclear how red supergiants behave near the end of their lives. The shrinking size could also be evidence of an as-yet-unidentified pulsation in the star.

The surface of Betelgeuse is known to wobble in and out, fed in part by the roiling energy of convection beneath its surface. Two such pulsations are already known – one seems to start anew each year, the other every 6 years.

Since this observation shows a progressive decrease in the size of the star over 15 years with a consistent set of measurements.

The Hadwiger’s conjecture


Speaking about graphs, the Hadwiger number (G) of a graph G is the largest integer h such that the complete graph on h nodes K h is a minor of G. Equivalently, it is the largest integer in a way which any graph on at most (G) nodes is a minor of G. The Hadwiger’s conjecture states for any graph G, (G) number of G. It is well-known by mathematicians that for any connected undirected graph G, there exists a unique prime factorization with respect to Cartesian graph products. If the unique prime factorization of G is given as G1 G 2 ::: G k, where each G i is prime, then we say that the product dimension of G is k. Such a factorization can be computed efficiently.

Studying the Hadwiger’s conjecture for graphs in terms of their prime factorization. It shows the Hadwiger’s conjecture is true for a graph G if the product dimension of G is at least 2 log ( (G)) + 3. In fact, it is enough for

 

 

This approach also yields (almost) sharp lower bounds for the Hadwiger number of well-known graph products like d–dimensional hypercubes, Hamming graphs and the d–dimensional grids. In particular, we show that for a d–dimensional hypercube Hd, 2b