Rita Levi-Montalcini, artist of science


portrait by orticanoodles - source: deviantart | flickr
Rita Levi-Montalcini was born on the 22nd april 1909 at Turin, Italy. In 1938 she came in Belgium because of the italian racial laws. After the war, she came back in Italy, at Asti, where she prepared a little laboratory in order to study the nervous system of chickens. In 1947, with her friend Renato Dulbecco, went in USA where she worked until 1977. In 1986 she was awarded the Nobel Prize in Physiology/Medicine with her pupil Stanley Cohen
for their discoveries of growth factors.
About the potential of the NGF, she wrote in her Nobel Lecture:
For instance, whenever cell death of specific neuronal populations may be linked to a decreased local availability of neurotrophic factors, such as NGF, its exogenous supply or stimulation of its endogenous production via pharmacological agents may offer a promising approach to presently incurable diseases.
About the role of the women in science, she said:
Humanity is made ​​up of men and women must be represented by both sexes.
In 1975 she was was supported by the italian farmaceutical industry Fidia, but in about a decade was discovered that the advetrised drug was harmful. About this story she said to Riccardo Chiaberge:
Of course, I must admit that I yelled to see my name linked to Fidia. But I thought it was the price to pay, I don't care about anything to get some help for research. If we prevent the industry to help the laboratory, we die.
She had aprecise opinion on the relationship between young people and technology:
Today, compared to yesterday, young people benefit from an extraordinary breadth of information, and the price is the hypnotic effect exerted by television screens disaccustoming them to reason (in addition robbing them of time to devote to the study, sports and games that stimulate their creative capacity). They create for them a definite reality that inhibits their ability to "invent the world" and destroys the charm of the unknown.
In this sense she was an example for all of us:
I lost a little the eyesight, much the hearing. At the conferences I don't see the projections and don't hear so good. But I think more now than when I was twenty. The body does what it wants. I am not the body, I am the mind.
She passed away on the 30th december 2012 at Rome, Italy.
I've never been able to keep a log. Everything in me is imagination, intuition. Nothing is scientific.
I am not a scientist, I'm an artist of science.

Levi-Montalcini R. (1987). The nerve growth factor: Thirty-five years later, Bioscience Reports, 7 (9) 681-699. DOI: (pdf)
Quotes by Rita Levi-Montalcini (italian)
Biographies on Wikipedia: italian | english
An interview with Tullio Regge (italian)

Mickey Mouse at the CERN

The most famous laboratory of the year is certanly the CERN thanks to the discovery of a new boson that it seems equal to the boson predicted by Peter Higgs et al.
CERN was established in 1952 and formed in 1954. Currently the experiments are carried with the LHC (Large Hadron Collider), but the previous accelerator ring was LEP, Large Electron-Positron Collider, that was used from 1989 to 2000. In particular in 1985 Alessandro Bencivenni, an italian disney writer, went at CERN and, inspired by the announced LEP, he wrote a story setted at the swiss laboratory, Mickey Mouse and the nuclear accelerator (Topolino e l'acceleratore nucleare), never published in english, so I decided to translate the cartoons about the explanation of the device and the experiment.
The popularizer is Atomo Bleep-Bleep, a charachter created by Romano Scarpa in Mickey Mouse and the Delta Dimension (first italian edition: 1959; first english edition: 1981 in Great Britain). I hope to write something about Atomo Bleep-Bleep, Doctor Einmug and the Delta Dimension in a future post, but for now I hope you can enjoy with this extract from the story, drawned by Massimo De Vita (I must remember that copyright is Disney):

Genetics, evolution and Turing's patterns

posted by @ulaulaman about #Turing #genetics #biology #evolution #morphogenesis reaction-diffusion system
I've just written a post about the theory of patterns in nature started by Alan Turing, and I describe the reaction-diffusion system: in the system there are an activator and an inhibitor molecule of morphogenesis. The dynamics between activator and inhibitor generates tha patterns and we can describe it with the following mathematica relation: \[u_t = d \Delta u + f (\gamma, u)\] where $u$ is the position of the gene, $u_t$ the diffusion speed, $d$, $\gamma$ real constants.
It's really interesting observe that recently the Turing model about patterns was applied also to the study of the evolution of genes, in particular to study the generation of digit patterning.
The story start from the Hox genes:
Hox genes are a group of related genes that control the body plan of the embryo along the anterior-posterior (head-tail) axis. After the embryonic segments have formed, the Hox proteins determine the type of segment structures (e.g. legs, antennae, and wings in fruit flies or the different vertebrate ribs in humans) that will form on a given segment. Hox proteins thus confer segmental identity, but do not form the actual segments themselves.
So the team try to mute some of the Hox genes in order to see if the number of digits decrease, but they surprisingly observed that they can add more and more digits in their mutant mouses (they arrived at 14 digits!). And they can explain this behavour with the reaction-diffusion model: in the following picture you can see the experimental results (the first three rows) and the computer simulation that used Turing's model:

Physics' Cabinets

Translation from M. Leone, A. Paoletti, N. Robotti (2009). La Fisica nei "Gabinetti di Fisica" dell'Ottocento: il caso dell'UniversitĂ  di Genova Il Giornale di Fisica, 50 (3), 135-154 : 10.1393/gdf/i2009-10106-9 (pdf)
Origins and development of Physics' Cabinets in Italy
From the seventeenth century, with the birth of Experimental Physics, new scientific instruments made their appearance. These instruments differed radically from the vast majority of antique instruments, because the latter had essentially practical purposes, such as navigation or surveying. Tools such as thermometers, barometers, vacuum pumps and so on, were instead true "physical machines" in order to enable the observation of natural phenomena and demonstration of physical laws according to the experimental method. Gradually, between the end of the seventeenth century and the beginning of the eighteenth century, the "physical machines" found a specific site of collection, often called "Physics' Cabinet".
The end of the seventeenth century also marks the debut of a new way of teaching physics in academia, and in particular, as first happened at the Universities of Oxford, Cambridge, London, Leiden, the demonstration with physical machines. Among the most skilled demonstrators we can remember the figure of the abbot Jean-Antoine Nollet, whose treatise Leçons de physique expérimentale (published in Paris between 1743 and 1748) has more than 350 experiments. Very often the physical machines were designed for entertainment of the cultured nobility of the time, and sometimes the devices were also found in the houses of wealthy people and principles. Considerable fame had some private Physics' Cabinets as one of Tsar Peter the Great, Lord Cowper in Florence and Laura Bassi in Bologna, all active in the mid-seventeenth century. Equally significant was the Physics' Cabinet of King Ferdinand II of Bourbon in Naples, active in the following century.
In the universities physical machines were first owned by the same teacher in experimental physics that often made "private lessons" that is paid by the university and lectured by professor often in "his own house". These "machines" were later purchased by universities themselves and flowed, along with donations from private collections, in the Physics' Cabinets, generally established by resolution of the universities. Between the eighteenth and nineteenth century were born in Italy many important Physics' Cabinets. One of the first was that of Turin, whose origins probably date back to 1721. Other important Cabinets were built in Padua (with John Poleni's Theatre of Experimental Philosophy, dating back to 1740), Bologna (the development of which, dating back to 1745, was contributed by Pope Benedict XIV with important donations), Rome (Physical theater of Wisdom, 1748), Perugia (founded by Luca Antonio Pellicciari in 1759), Pavia (1771), Modena (dating from 1772, the date on which Francis III was officially called Fra Mariano Morini of Parma to teach the "General Physics"), Genoa (1784), Naples (Physics' Cabinet of King Ferdinand II of Bourbon, 1813), Urbino (1832).
Special funds were allocated also for the purpose of payment of the "machinist", a skilled craftsman assigned to the maintenance of the "machines" and who performed physically the demonstrative experiences as explained by the "Professor". This character, "often a man of science, he was a skilled craftsman, able also to create new equipment at the request of the teacher. The machinist also had the task of improving and adapting instruments bought by Italian, French, English, German builders or being legacies. Sometimes the same professor was manufacturer and inventor of instruments or he followed closely the realization."
Although the academic Cabinets of Physics were born from the needs of teaching and studing, also the discolsure of the new experimental science was considered important. For example, in Rome, during the pontificate of Pius VI (1775-1799), the teaching of physics was regulated, stating also that during the holiday period, for fifteen days, the professor had to keep at the Physical theater many public lectures with experiments carried out by the machinist.

The Physics' Cabinets and the congresses of Italian scientists
The activity of the Physics' Cabinets, particularly in the Nineteenth Century, however, was not limited to the demonstration of the laws of physics or the repetition of measures that are particularly significant for educational or informational purposes. An important, but until now largely neglected by historical analysis, was the research in physics that was being developed in them. Significant witness of this are the scientific contributions presented during the twelve Congress of Italian Scientists, held annually between 1839 and 1847 (respectively in Pisa, Turin, Florence, Padua, Lucca, Milan, Naples, Genoa, Venice), and later in 1862 (Siena), in 1863 (in Palermo) and in 1875 (in Rome), and in which the experimental results, achieved for the most part in the various Physics' Cabinets located in Italy, were announced.
The Physics' Cabinets, also, as rightly held to be instrumentally and scientifically well-equipped facilities, played a decisive role in the actual performance of these Congress of Italian Scientists. At that time, it was so great the interest and attention to the experimental aspect of physics that before the communication of some new experimental discovery, it was customary that the Presidents of the Chambers of Physics asked to a commission specially appointed, or to the same alleged discoverer, to repeat the experiment in public that was the basis of this discovery. This could be done thanks to the local Physics' Cabine, which provided the necessary equipment.

The secret origins of the Moon

posted by @ulaulaman about #Moon formation #astronomy #Earth with Italo Calvino quotes
Our satellite, the Moon, is really fascinating, not only for artists and poets, but also for scientists. For example the first, precise description of the Moon was made by Galileo Galilei in the Sidereus Nuncius:
One of the problems that the astronomy try to resolve about the Moon is its origins: for example in the beginning of the Twentieth Century it was developed the Earth-Moon Theory, that was reviewed by LeRoy Hughbanks(8):
"The moon," says Prof. Percival Lowell, "did not originate as a separate body, but had its birth in a rib of earth." Doctor Lowell is an ardent sup- porter of "the earth-moon theory," and his views and deductions are frankly stated in his two last scientific works, "Mars as the Abode of Life" and "Evolution of Worlds," both of which are publications of the Macmillan Company, New York.
In the discussion has a really great importance George Darwin with his works about the tidal friction(6) and the viscous spheroids(5):
Following Sir George Darwin, the Moon would have been detached from the Earth because to a solar tide. The attraction of the Sun acted on the covering of lighter rock (granite) as on a fluid, lifting one hand and tearing it to our planet. The waters that covering the entire Earth were largely sucked down by the abyss that had opened by the escape of the Moon (i.e. the Pacific Ocean), leaving uncovered the remaining granite, which fragmented and wrinckled itself into the continents. Without the Moon, the evolution of the life on the Earth, although it had been, would have been very different.(2)
Another good description of the earth-moon theory was given by Andrew Patterson:
In brief, the theory is that when the earth had cooled, from its molten condition sufficiently to have a crust of solidified matter something like thirty miles thick over its entire surface, it was revolving so rapidly that gravitational attraction and centrifugal force practically balanced each other. For some reason, perhaps some vast and sudden cataclysm, a large portion of this crust was thrown off the earth, and by tidal action was forced gradually outward in a spiral path. In order to form the moon, a mass of this crust about thirty miles thick and of area nearly equal to the combined areas of the present oceans on the earth must have been thrown off. It is supposed that this immense amount of crust was largely taken from the present basin of the Pacific, and that the remaining parts of the earth's crust, while it still floated on a liquid interior, split along an irregular line into two pieces which floated apart, and the gap between these two parts was later filled with the waters of the Atlantic.(7)
But following Gerstenkorn(11) we could arrive to a variation of this picture:
Following H. Gerstenkorn's calculations(11), developed by H. Alfven(9, 10), Earth's continents would be fragments of the Moon fell on our planet. The Moon in origin would also be a planet gravitating around the Sun, until such time as the proximity to the Earth derailed her from its orbit. Captured by Earth's gravity, the Moon came up more and more, tightening its orbit around us. At one point, the mutual attraction began to deform the surface of the two celestial bodies, raising high waves which were detached fragments whirling in space between Earth and Moon, especially fragments of lunar matter that fell on Earth. Later, under the influence of our tides, the Moon was pushed away to reach its present orbit. But part of the lunar mass, perhaps half, was left on Earth, forming the continents.(3)

The practical value of science

I have endeavored to state the higher and more abstract arguments by which the study of physical science may be shown to be indislensable to the complete training of the human mind, but I do not wish it to be supposed that because I may be devoted to more or less abstract and unpractical pursuits I am insensible to the weight which ought to be attached to that which has been said to be the English conception of Paradise - namely, ' gettinig on'. Now the value of a knowledge of physical scienice as a means of getting on, is indubitable. There are hardly any of our trades, except the merely hukcstering ones, in which some knowledge of science may not be directly profitable to the pursuer of that occupation. An Industry attains higher stages of its development as its processes become more complicated and refined, and the sciences are dragged in, one by one, to take their share in the fray.

Thomas Huxley, Science vol.1 n.1 (1880)

The network of scientific journals

At the beginning of 2012, Science published a briefly paper about the coercitive action of the editors in most of the scientific journals in world:
We find that coercion is uncomfortably common and appears to be practiced opportunistically(1)
One of the most coercitive practice is to say to the authors to cite in their paper more source from the journal where the work is submitted (the practice of coercive self-citation is common in the business disciplines, for example). Now a new research try to describe the interaction between scientific journals with a really particular network:
In the network, an arrow from journal A to journal B represents a “resubmission link,” that is, an article that was submitted to and published by journal B after submission to journal A. This network can be used to learn more about publication strategies and perceived journal importance than is available in citation networks alone(2)
The idea is: you submit to a journal with an high impact factor, your paper was rejected for example because is too specialistic, and you resubmit to another journal, and in this case your paper is accepted. And, incredible:
Resubmissions were significantly more cited than first-intents published the same year in the same journal(2)
Keith Bowers, commenting the results of the paper, write on the same issue of Science:
Journal editors could increase the quality of papers published in their own journals by exacting more rigorous standards for revision without rejecting them. Providing authors more opportunities to revise and resubmit manuscripts following peer review, while being clear to authors that substantial improvement must be made before a final decision is reached, would increase the citation impact of an editor's own journal.(3)
As is he right?
(1) Wilhite A.W. & Fong E.A. (2012). Coercive Citation in Academic Publishing, Science, 335 (6068) 542-543. DOI:
(2) Calcagno V., Demoinet E., Gollner K., Guidi L., Ruths D. & de Mazancourt C. (2012). Flows of Research Manuscripts Among Scientific Journals Reveal Hidden Submission Patterns, Science, 338 (6110) 1065-1069. DOI:
(3) Bowers E.K. (2012). Journals: Increase Revisions, Not Rejections, Science, 338 (6110) 1029-1029. DOI:

Proofs without words: Ptolemy's theorem and cosine's law

Derrick W. & Hirstein J. (2012). Proof Without Words: Ptolemy’s Theorem, The College Mathematics Journal, 43 (5) 386-386. DOI: (via Cut the Knot)
Kung S.H. (1990). Proof without Words: The Law of Cosines, Mathematics Magazine, 63 (5) 342. DOI: (pdf)
Law of cosines via Ptolemy's theorem
Kung S.H. (1992). Proof without Words: The Law of Cosines via Ptolemy's Theorem, Mathematics Magazine, 65 (2) 103. DOI: (pdf)

A is for atom

#video posted by @ulaulaman about #nuclearenergy
A is for atom is a promotional animation written by True Boardman and directed by Carl Urbino with music by Eugene Poddany. It was commisioned by General Electric to John Sutherland and distributed by the Sutherland Production in 1953.
You can download the original video, that it is in public domain, from archive.org.

via boingboing

Looking through an opaque material

posted by @ulaulaman about #JacopoBertolotti #physics #optics #opaque #matter
I am proud to publish a feature article about the research word of a Wikipedia's friend like Jacopo Bertolotti. The work was finally published on "Nature", that decided also to honor the paper with the cover.
I admit to have received the paper a couple of weeks ago, so I hope to have made ​​a good service to Jacopo and all of his colleagues.


Recently one of my students asked me why glass is transparent while other materials are not. Its transparency is substantially due to the interaction between the electrons of the glass and the incident light, and so from the interaction between the photons (or electromagnetic radiation) and matter. A photon, when it interacts with matter, can be absorbed, reflected or continue on its way without change. These different behaviors are due to the energy levels occupied by the electrons of the atoms that constitute matter, in particular by the energy difference between these levels. We know, thanks to the photoelectric effect and the explanation given to it by Einstein, that the electrons are excited by the incident photons only if the energy of these photons is equal to (or greater than) the energy required to jump to another level. This means that if the light does not excite the electrons of the material, this is transparent to its passage, just as occurs in the glass: the visible light, in fact, has not enough energy to excite the electrons of the glass, which is therefore transparent to its passage, despite the rays of light are reflected.
Now, if we take a sheet of glass and do hit by light from one of its ends, a part of the rays will be reflected and then detected by a device (such as our eyes) placed for example at the opposite end. Not all reflected rays, however, follow an equal path and therefore not all the rays reach the eyes at the same time.
Something similar also occurs when light passes through the glass of our windows: the light rays don't travel all at the same speed.
In order to enable to all the rays of light to reach the detection point at the same time one can construct a structure which gradually tapering as it approaches the ends, i.e. it builds a lens.
One of the ways to use a lens is for example for the magnification of objects, but not all magnifications can be made using the lenses that take advantage of the visible light. If, for example, we have some objects that are at a scale of less than 200 nm, the usual optical lenses are not able to resolve their details. Unless you build a HIRES(1) (High Resolution Enhancement by Scattering Index) lens.
This lens, developed by the group of van Putten and Bertolotti (our Jacopo!) consists of:
(...) of a homogeneous slab of high-index material on top of a strongly disordered scattering layer. The disordered layer breaks the translational invariance of the interface, which enables incident light to be coupled to all propagating angles inside the highrefractive-index material as shown in figure.
Yet multiple scattering also scrambles the wavefront creating a speckle-like pattern on the object plane that itself cannot be used for imaging. Therefore we manipulate the incident wavefront in order to force constructive interference of the scattered light at a position in the object plane of our HIRES-lens.(1)

Science education and comics

posted by @ulaulaman about #science #physics #comics #UncleScrooge
In 2002 F. Javier Perales-Palacios and José M. Vílchez-González studied the impact of comics and cartoons in the study of physics. They arrived at the following conclusions:
  1. Teaching physics by showing cartoons constituted a clear incentive in the students' attitude towards the subject.(1)
  2. Students' misconceptions to a certain degree parallel the incorrect physics in the cartoons. It is quite possible that the cartoons have reinforced these misconceptions from an early age.(1)
  3. Use of TV in the classroom to present real images (for instance, the behaviour of bodies orbiting the Earth, the movement of passengers in a bus, and so on) and contrast the real and the fictitious planes facilitates conceptual change.(1)
  4. This type of strategy can bring physics teaching closer to the communications media that most interest the students, and therefore reduce the barrier between School Science and everyday knowledge.(1)
  5. The image of science and scientists presented in the cartoons was typical and students who participated in the experiment also held this stereotyped image.(1)
  6. There was a great diversity in the results between individuals and between groups. (...) The student group clearly surpassed the teachers in the number of phenomena identified.(1)
In particular the points 2. (the incorrect physics in cartoon) and 5. (the stereotypes about science and scientists) are deepen in a recent paper by the same two authors:
We have been able to ascertain that cartoons do distort the image of science and its environment. Very often it is presented as something distant and far-removed from everyday life, thus hiding its basic objectives (explaining the world that surrounds us) under meaningless headings that make use of 'strange' (often mistaken) terms or huge and meaningless mathematical expressions. This occurs even for those familiar with the subject matter (thereby strengthening the elitist image of science), and sometimes even directly presenting some of the preconceived ideas that the bibliography acknowledges as being characteristic of adolescents. Comics also offer a distorted image of these questions, similar to the one that is presented in cartoons 'if they were silent'.(2)
The two researchers are warry about the influence of these two media, but I think that they forgot (read, for example, the point 1. of the 2002's paper) the theacher's key role in the education. Comics, indeed, are a great opportunity to introduce in a very simple way physics in classroom:
(...) educators should not underestimate the importance of learners’ interests. These interests can work for us in two ways. They can provide hooks, and they offer context. To most physics teachers, physics is clearly a subject that explores the most fundamental aspects of nature, which encompasses the smallest and largest scales we can envisage, and which deals with the most fascinating questions and phenomena. Some of our students feel the same, and come to classes with an enthusiasm to learn more. Unfortunately, however, many students do not initially share our enthusiasms.
It is so much easier to learn when we are interested in the subject matter. Learning is most effective when we are motivated to learn, and engaged by the learning process.(3)

Mathgenerator Editions: Differential Analysis

After the publications of some abstracts (with the pdf version) from papers generated with mathgen and scigen, Today I propose you a book generated with the downloadable code of mathgen. I use the following code:
./mathgen.pl --product=book --mode=zip --output=mybook.zip --author="Gianluigi Filippelli"
In this way the software generates also the LaTeX code, and so I could eventually modify the book. For example I add a cover: first of all I generated it using Magazine Cover generator. In order to add the cover, first of all I insert the following code in the preamble:
\usepackage{geometry}
\geometry{top=0cm,bottom=0cm,left=0cm,right=0cm,nohead,nofoot}
\usepackage{graphicx}
\usepackage{calc}
And after I add the following code after \begin{document}:
\frontmatter
\pagenumbering{gobble}

\ begin{center}
\includegraphics[width=5.8in,height=8.8in]{cover.jpg}
\ end{center}

\newpage
In order to create an interactive pdf I also add the following package:
\usepackage{hyperref}
\hypersetup{
pdfpagemode=UseOutlines,
%pdfstartview=FitV,
bookmarksopen,
bookmarksopenlevel=-1,
pdftitle=Differential analysis,
pdfauthor=Gianluigi Filippelli,
pdfsubject=mathematics,
pdfkeywords=mathematics
%pdfpagemode=FullScreen
}
You can download the results from minus.com
I hope that you can enjoy yourselfs with mathgen and scigen!

Journal of Mathgenerators, vol.1 issue 1

It's on-line the first issue of a new, impressive journal. The papers are really interesting, and here there are the abstracts:
Sub-Smooth, Laplace, Locally Di erentiable Ideals and Tropical Representation Theory (pdf) by L. Marino, V. Wiles, A. Huygens, C. Grassmann
Suppose every Pappus, isometric matrix is right-regular. Is it possible to study topoi? We show that $y \ni \Xi'$. Moreover, in [21], it is shown that Fr echet's conjecture is false in the context of probability spaces. Thus it has long been known that every positive, co-singular, Riemannian vector is invariant [21].
Stability methods (pdf) by G. Filippelli
Let $c = \pi$ be arbitrary. In [32], the authors described Cartan, bijective, solvable subrings. We show that $\bar f$ is not larger than $\Xi^{(\beta)}$. It is well known that $C_Q \sim i$. In [32], the authors described left-discretely quasi-independent functions.
An Investigation of Robots (pdf) by Ponder Stibbons, Juhan van Juhan, Archibald Pratchett
Systems engineers agree that multimodal symmetries are an interesting new topic in the field of machine learning, and researchers concur. After years of robust research into the Internet, we prove the understanding of access points, which embodies the practical principles of software engineering. We introduce new cooperative modalities, which we call Yarn.
$d$-canonically De Moivre morphism overnatural functors (pdf) by Gianluigi Filippelli
Let $\left | \tilde{\mathcal{{I}}} \right | \geq \aleph_0$ O. F. Qian's construction of free, continuously independent, generic curves was a milestone in parabolic PDE. We show that Noether's condition is satis ed. Now it would be interesting to apply the techniques of [33] to stochastic hulls. Next, in [37], the authors constructed groups.
Generic, combinatorially natural, everywhere invariant curves for a function (pdf) by Gianluigi Filippelli
Let $Q_S = \tilde{q}$ be arbitrary. Y. Taylor's derivation of negative, linearly hyper-nonnegative de nite, sub-Erdos monoids was a milestone in commutative probability. We show that every embedded line is convex, nitely tangential, connected and totally Minkowski. N. Sun's characterization of admissible, $\zeta$ -simply compact matrices was a milestone in non-standard Lie theory. So is it possible to compute embedded, Cli ord equations?
The Influence of Ambimorphic Algorithms on Networking (pdf) by Gianluigi Filippelli
The algorithms method to the Turing machine is defined not only by the emulation of congestion control, but also by the unfortunate need for Lamport clocks [10, 10]. Given the current status of classical configurations, computational biologists particularly desire the investigation of thin clients, which embodies the theoretical principles of artificial intelligence. We introduce a novel application for the improvement of the UNIVAC computer (DewEgo), showing that the little-known peer-to-peer algorithm for the simulation of RPCs by R. Sasaki et al. is recursively enumerable.

Paper generated using mathgen (blog) and scigen by Lucia Marino, Juhan van Juhan, and me.
Cover generated by Magazine Cover

Don Rosa's scientific wisdom

written by Piero Patteri and @ulaulaman about #DonRosa #physics #science #disney #comics
Share photos on twitter with Twitpic
I finally met again Piero Patteri at Comunicare Fisica, a workshop about the comunication of physics, and Piero gave to me a book that the italian Disney's fun site Papersera.net realized for Don Rosa in 2011. Because I will be to Lucca Comics in order to speak about comics and science, I decided to publish here the english version of the article that I written with Piero for the book "Don Rosa: A little something special".
The physical law of the real world are enforced in a very loose way in the comic book world. Bouncing, smashing, hitting in harmless crashes are common events in the strips, at least since the brick thrown by Ignatz against Crazy Cat, actually continuing the paroxysm of comic actions in the mute movie era. Therefore is really surprising, and amazing from a physicist point of view, to find a comics artist showing a constant effort of supporting the humoristic side embedding his plots in a rather coherent physical frame.
Here we account for our feelings when exploring the features of the Rosa's physics both in the voyager in the micro world, in The Incredible Shrinking Tightwad, both in the outer space in Solar System in Attack Of The Hideous Space Monsters, each of them a must subject in the work of sci-fi writer. After reviewing the most amusing gag offered by teletransport in On a Silver Platter we eventually land in the realm of the Extraordinary Physics acting in On stolen time, and A Matter Of Some Gravity
In the micro world
The reducing machine appearing in The Incredible Shrinking Tightwad is an explicit citation of the Carl Barks' machine in Billions in the Hole, but the device found by ducks in the garret of Uncle Scrooge is defective, and once the squeezing has been started, the process proceeds indefinetely. So, beside the discovery of new dangerous features in an increasingly small world, the out-of-control evolution in the Rosa's tale enhance the thrilling plate after plate. In Barks' tale the size reduction causes a sudden flipping of hunter/prey role between ducks and ants, and just the timely rescue by Gyro Gearloose save their lives. Here Uncle Scrooge and Donald Duck fight at every stage, jumping on the coins in the bin like on pebbles in a stream, until these become the slippery walls of huge crack, or chasing away a ugly louse in the hair which soon becomes a monster; in the end in the dirty pocket of a Beagle Boy, the germs resembling mithological monsters Medusa or One-hundred-eyed Argo are on the point of overcoming them and only a deus-ex-machina intervention seems to be able to rescue them.
On the other hand, by the exploration of the new environment looking for an escape they discover realistic details, such as the grease on a hair, or the wood yarn embedded on the surface of a sticky plum; one could say they had nothing to the plot, but just their 'useless' presence conveys the feeling that ducks are really falling in an extraordinary, but extremely realistic world. So the way out jumping on the spikes of shaven beard is not a sudden trickery but the logical opportunity built all along the tale.
The hastening of events sometime reminds Hitchcock's hunting/escaping sequences, such as in North by Northwest or Vertigo, and like in the movies by the Master of suspence, the choching solution bursts into the stage, with Uncle Scrooge becoming again full size in the hand of a Beagle Boy

In the outer space
Again the foolish switch-on of a misterious device affects the physical property of the Uncle Scrooge bin. This time it looses its wheight, and the ducks must pursue it in the space, hoping to success in reversing the operation of the device.
The comment in the italian edition on Zio Paperone #132 emphasizes the tribute to classic sci-fi movies. Although this is true as far as the dive in a space-time tunnel is concerning, quoting the Star Trek and Star War sagas, we think that most of details in the tale are an humorous tribute to Paperino e il razzo interplanetario. The space-ship travel among the asteroid belt and the encounter with a family of precious mineral digger match the corresponding sequences by Luciano Bottaro.
The parodistic side of the tribute is not only in the personality and aspect of the aliens, but also in minor characters, as the chichen, mistaken for the chief of ducks, owing to a red crest which recall the Rebo crest. The interrogation of the chicken in the last cartoon is quoting the same probing of Donal Duck by Juppiter officers.
While these points are in the realm of the 'classical sci-fi physics', Rosa adds an additional concept to his Extraordinary Physics, to be discussed later in deeper insight, to explain the operation of the antigravity device: it cancels the inertia, so that the sudden hit on the Moon does not destroy the asteroid and the bin on it. Besides recalling these amazing points, we cannot forget that in Don Rosa's drawings there is a astonishing anticipation of the dynamics of the dramatic events of 9/11.

Martin Rees: From Big Bang to the Biospheres

posted by @ulaulaman about #MartinRees #BigBang #universe #astronomy
In order to celebrate the anniversary the first observation from x-ray astonomy, the Brera's Astronomical Observatory in Milano organized the international congress X-ray Astronomy: toward the next 50 years!
To the edge of the scientific congress, the organization propose also some public events, starting from the first day, the 1st october, with a talk by the Astronomer Royal, Martin Rees.
From Big Bang to the Biospheres is a great journey in the story of the astronomy, the older science, starting from Galileo Galilei, with the invention of the telescope, and Isaac Newton, with the page from Principia about the escape velocity from Earth.
We immediatly jump to the space exploration, with the launch of the Sputnik and the Time's cover dedicated to the first man in space: Yuri Gagarin. Of course also a bit homage to the first man on Moon: Neil Armstrong.
The exploration of space continued with the satellites mission: the european Mars Express, with its spectacular images, and the last Mars' rover, Curiosity.
And after the exploration of Jupiter's satellites (Io, Europa), it arrives Cassini with its spectacular shots, in particular the Sun eclipsed by Saturn and the Huygens descending and landing on Titan.
Robots explore solar system but will follow people!
The next step in our research is to find planets beyond our Solar System: in order to perform this quest we could use two methods: the gravitational lens and the transition.
Using the first method we found 555 planets, Jupiter- and Saturn-like, but if we want to find Earth-like planets we must use the transition method, and this is the reason of the design and launch of Kepler mission.
Also the exploration with telescope could be most useful for our purpouse. We can use space telescopes, like the famouse Hubble Space Telescope, or the Earth telescopes, like the ESO's Extremely Large Telescope, that will be the greatest telescope on the planet!
With the telescopes we can observe a lot of space objects, like supernovae. The first observation of these wonderful explosions is dued by chinese astronomers, but only with Fred Hoyle we have a really powerfull theory about these objects and the nuclear interactions involving in it.
These interstellar explotions are very important in the diffusion of the heavy chemichal elements in the universe, but there are other spectacular interactions like galaxies collisions, that could be described thanks to computer simulations:

Bohr and the horseshoe

an anecdote about #NielsBohr via #GeorgeGamow
Wrote George Gamow in "Thirty Years that Shook Physics":

Above the front door of his country cottage in Tisvilde he nailed a horseshoe, which is proverbially instrumental in bringign luck. Seeing it, a visitor exclaimed: "Being as a great scientist as you are, do you really believe that a horseshoe above the entrance to a home brings luck?" "No," answered Bohr, "I certainly do not believe in this superstition. But you know," he added with a smile, "they say that it does bring luck even if you don't believe in it!"

A Day in the life of ESO

the video about the #ESO50years celebration day posted by @ulaulaman
In order to celebrate the 50th anniversary of the ESO, it was realized a streaming with a lot of talk by some ESO's researchers. After the celebration day, there was released the video of the weblive:
In the image a screenshot from Fernando Papat's talk with a quotation by Giorgio de Santillana

Is it the Higgs? The spin will tell us!

a couple of video about #Higgs via @CMSexperiment posted by @ulaulaman
The CMS experiment posted on its Google Plus page a couple of video about the new boson and the future research of its spin, an important tool in order to understand if the new particle is a Higgs boson or someone like it, but with some, little differences:

The birth of a planet

partially translated by @ulaulaman from a post by @_starblogger_
When I write about the Nice model, I explain how a group of researchers try to explain the birth of our Solar System. The approach of the group is to design some simulations about the dynamics of the whole Solar System. This approach is very used in physics, in particular when calculation by hand are too complicated. So, today I would propose you a video with the interview to a new group that perform some simulations in order to explain how a planet could born. The group, leaded by Sally Dodson-Robinson is
(...) carrying out a series of computer simulations of the proto-stellar disks. The simulations provide some important parameters, such as the turbulence and the temperature of the disc, which influence how and where the planets are formed. In a disk with a high percentage of turbulence, the particles forming the planetesimals move very quickly and go away from each other. At the other hand, in a less turbulent situation, there will be a much more probability that the particles collide and are aggregated together in order to give rise to future planets. In 1988, it was known only an extrasolar planet, and today almost 2400 waiting to be confirmed. Therefore, understanding those favorable conditions for the formation of a planet will allow astronomers to discover more and more of them and, at the same time, will provide important new clues about the birth and evolution of the Earth and then of the Solar System.(1)

(1) Translated from AstronomicaMens

The invisible universe

posted by @ulaulaman about #x-ray #astronomy #riccardogiacconi #universe #exhibition #milano
Today will be open in Milano an exhibition about the x-ray astronomy in order to celebrate the discover of the first cosmic x-ray source in 1962. And today I try to resume the story of this research.
The beginning of this branch of the astronomy is in 1946 when Bruno Rossi, who has worked with Enrico Fermi during Manhattan project, started to deal with physics of cosmic rays while teaching at MIT about X-ray. In 1958, with the birth of the American Science & Enginnering (AS&E), Bruno Rossi joined it as chairman of the board of directors and scientific advisor and a year later he called to work even Riccardo Giacconi. One of the first experimental successes includes the launch of the first rocket equipped with detectors for X-rays in 1962. The team of this project as well as Giacconi included, Herb Gursky, Frank Paolini, and Bruno Rossi. With this mission, it was reported the first cosmic X-ray source outside the sun, Scorpius X-1 in the constellation Scorpius.(1, 2)
The uniqueness of the observations of Scorpius X-1 is due mainly to its properties. In fact, while the X-radiation from the sun has an intensity that is approximately 10-6 times than visible light, Scorpius X-1 has a X-brightness that is 103 times higher than its same brightness in the visible light. It was subsequently discovered that its intrinsic brightness is 103 times that of the Sun!(1)
There was therefore in front of the discovery of new celestial objects, which had X-rays produced in different physical processes compared to the processes made in the laboratories of the Earth, since their efficiency (99.9%) was unmatched!(1)
1960s were, therefore, rich for X-rockets into space, but for the very first X-satellite was launched only in 1970 thanks to a new group leaded by Giacconi(1):
The X-ray astronomy achieved great success with the launch of the first satellite dedicated to X-rays, Uhuru, launched in 1970, with it performed an initial mapping of the X-ray sources in space. It was discovered that the universe is full of objects that emit X-rays, from the black holes to the pulsars, to the binary stars. In fact after this mission, the X-ray astronomy assumes an important role between the international scientific community. It soon became clear that, in order to better understand the secrets of the sky, instead of simply detecting the X-rays, it would be useful to make observations with a telescope sensitive to X-rays. The development of this telescope began with the entry into AS&E team of Giuseppe Vaiana, who leaded the program about the solar X-ray astronomy and the construction of the first telescope. In 1973, Skylab was launched, the U.S. space laboratory directed by Vaiana, that, in addition to various scientific experiments, carried on the observation of the Sun and the corona in X-rays. In 1978 it was sent into orbit the Einstein Observatory, the first X-ray space telescope. The important discoveries of the ROSAT and Chandra followed.(2)
One of the successive results of astronomy X, always signed Giacconi, in this case with Ethan Schreier, was the discovery of an X-ray source around Cen X-3(1).
Very important discoveries of Uhuru, however, were mainly those concerning the existence of neutron stars and binary systems consisting of a visible star and an unseen companion, a black hole(1)!

In serach of the ETs with the distributed computing

published by @ulaulaman about #SETI #astronomy #distributed_computing
One of the most intriguing question of the mankind is if we are alone in the universe, if in a some little part of the cosmos it exists intelligent life. Starting from this quest, a lot of science fiction writers gave us some good sci fi novels. For example The Voyage of the Space Beagle by Alfred Elton van Vogt, inspired by the journey of Charles Darwin on the Beagle. In this novel, during the search of alien life, the spaceship Argus found not only vestiges of vanished civilizations, but also interacted with real aliens.
But the research for other cosmic intelligences beyond the limits of our Solar System has also fascinated, for many reasons, the scientists themselves. It is famous the dinner (or maybe it was a lunch) where Enrico Fermi explained his equally famous paradox from which Frank Drake drew inspiration for his famous equation. And Drake became one of the founders of the SETI project(5), Search for extraterrestrial intelligence, a project that involved a lot of researchers around the world. This kind of research, which may seem absurd as to get the ghostbuster, is based, first, on the assumption that
(...) an alien civilization wishing to make contact with other races would broadcast a signal that is easily detectable and easily distinguishable from natural sources of radio emission. One way to achieve these goals is to send a narrowband signal. By concentrating the signal power in a very narrow frequency band, the signal will stand out among the natural broadband sources of noise.(1)
At the beginning SETI focused its activity on listening to radio signals from space. The type of signal that should be detected presents some problems: first, the frequency stability, caused by the acceleration of the transmitter and receiver(1), which for example they are influenced by the speed of rotation (around the axis, around the star). Solving this problem is not in principle impossible: certainly we know very well the properties of our planet in order to perform this kind of correction, but it is not the same thing for an alien planet. In this last case, the story is certainly very different, especially if the planet is completely unknown
An alien civilization narrowly beaming signals at the earth could correct the outgoing signal for the transmitter's motions, but a civilization transmitting an omnidirectional beacon could not make such an adjustment.(1)
One way to remedy is to use the Doppler effect(1), but this means making a lot of calculations, and answering to a lot of questions about the characteristics of the signal itself:
at what frequency will it be transmitted? What is its bandwidth? Will it be pulsed? If so at what period? Fully investigating a wide range of these parameters requires proportionally larger computing power.(1)
And we don't forget that we have to understand if the detected signal with a presumed extraterrestrial origin is not, in reality, of cosmic origin (i.e. produced by a star or a galaxy or some other not artificial object traveling in space).
All these calculations are extremely complex and require a much greater computing power than supercomputers. It is for this reason that in 1995, David Gedye, a project manager at Starwave Corp., proposed to use the distributed computing in order to create a virtual supercomputer: the birth SETI@home(2).
The first step in the construction of the project is to find a good radio telescope. The ideal candidate was the telescope in Arecibo, Puerto Rico, administrated by Cornell University and the National Science Foundation(2). This choice, however, had a small problem: the time of use. SETI could not have the exclusive use of the telescope, because it was already being used for various astronomical and meteorological researches. The problem was solved in 1997 by Berkeley's SERENDIP project, who developed a technique to use a second antenna(2).

Habemus papers (about the new boson)

posted by @ulaulaman thanks to @tanzmax @spimpompam #Higgs #boson #newboson #LHC #CMS #ATLAS #CERN
Finally Physics Letters B published the two papers by ATLAS and CMS about the discovery of the new boson at LHC (via tanzmax):
A search for the Standard Model Higgs boson in proton–proton collisions with the ATLAS detector at the LHC is presented. The datasets used correspond to integrated luminosities of approximately $4.8 \, fb^{−1}$ collected at $\sqrt{s} = 7$ TeV in 2011 and $5.8 \, fb^{−1}$ at $\sqrt{s} = 8$ TeV in 2012. Individual searches in the channels $H \rightarrow ZZ^{(*)} \rightarrow 4l$, $H \rightarrow \gamma \gamma$ and $H \rightarrow WW^{(*)} \rightarrow e \nu \mu \nu$ in the 8 TeV data are combined with previously published results of searches for $H \rightarrow ZZ^{(*)}$, $WW^{(*)}$, $b \bar{b}$ and $\tau^+ \tau^-$ in the 7 TeV data and results from improved analyses of the $H \rightarrow ZZ^{(*)} \rightarrow 4l$ and $H \rightarrow \gamma \gamma$ channels in the 7 TeV data. Clear evidence for the production of a neutral boson with a measured mass of 126.0 ± 0.4 (stat) ± 0.4 (sys) GeV is presented. This observation, which has a significance of 5.9 standard deviations, corresponding to a background fluctuation probability of 1.7 × 10−9, is compatible with the production and decay of the Standard Model Higgs boson.
Aad, G., Abajyan, T., Abbott, B., Abdallah, J., Abdel Khalek, S., Abdelalim, A.A., Abdinov, O., Aben, R., Abi, B., Abolins, M. & (2012). Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC, Physics Letters B, 716 (1) 29. DOI: 10.1016/j.physletb.2012.08.020
Results are presented from searches for the standard model Higgs boson in proton–proton collisions at $\sqrt{s} =$ 7 and 8 TeV in the Compact Muon Solenoid experiment at the LHC, using data samples corresponding to integrated luminosities of up to $5.1 fb^{−1}$ at 7 TeV and $5.3 fb^{−1}$ at 8 TeV. The search is performed in five decay modes: $\gamma \gamma$, $ZZ$, $W^+ W^−$, $\tau^+ \tau^-$, and $b \bar{b}$. An excess of events is observed above the expected background, with a local significance of 5.0 standard deviations, at a mass near 125 GeV, signalling the production of a new particle. The expected significance for a standard model Higgs boson of that mass is 5.8 standard deviations. The excess is most significant in the two decay modes with the best mass resolution, $\gamma \gamma$ and $ZZ$; a fit to these signals gives a mass of 125.3 ± 0.4 (stat.) ± 0.5 (syst.) GeV. The decay to two photons indicates that the new particle is a boson with spin different from one.
Chatrchyan, S., Khachatryan, V., Sirunyan, A.M., Tumasyan, A., Adam, W., Aguilo, E., Bergauer, T., Dragicevic, M., Erö, J., Fabjan, C. & (2012). Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC, Physics Letters B, 716 (1) 61. DOI: 10.1016/j.physletb.2012.08.021

To the previous papers, I add also the following (via spimpompam), that it could be interesting to read:
Following recent ATLAS and CMS publications we interpret the results of their Higgs searches in terms of Standard Model operators. For a Higgs mass of 125 GeV we determine several Higgs couplings from 2011 data and extrapolate the results towards different scenarios of LHC running. Even though our analysis is limited by low statistics we already derive meaningful constraints on modified Higgs sectors.
Klute, M., Lafaye, R., Plehn, T., Rauch, M. & Zerwas, D. (2012). Measuring Higgs Couplings from LHC Data, Physical Review Letters, 109 (10) DOI: 10.1103/PhysRevLett.109.101801 (arXiv)

The Maxwell's equations, the Beatles and the differential geometry

posted by @ulaulaman about #Maxwell #physics #mathematics #music #Beatles
The following video is a song about Maxwell's equations. Lyrics are written by David Olson with the basis of Let it be by Beatles.
Enjoy!
Interestingly, Maxwell's equations have been drastically reduced into a language of di fferential geometry. These four sets of equations which perfectly describe the theory of electromagnetism have been reduced to a set of two equations which lay the foundations of most new theories in the physical world today.
The most revolutionary quantum leap in the history of theoretical physics is the birth of general relativity and quantum eld theory (the standard model of elementary particle). These theories describe nature better than any physicist ever had at hand, although they have not been uni ed into a coherent picture of the world. One of the main ingredients of these theories is di erential geometry. Euclidean geometry was abandoned in favour of di erential geometry and classical eld theories had to be quantized.
Maxwell's equations in the language of di erential geometry lead to a generalization to these new theories, and these equations are a special case of Yang-Mills equations (beyond the scope of this essay), which is also gauge invariant and describe not only electromagnetism but also the strong and weak nuclear forces. This essay is nothing but the tip of the iceberg.
(from Maxwell's Equations in Terms of Differential Forms (pdf) by Solomon Akaraka Owerre)
Read also: The poem of the Maxwell's equations in pdf written by Lynda Williams.

A journey to the Moon

a collection of tweets about #NeilArmstrong collected by @ulaulaman

Pythagoras by Henry Swinburne

posted by @ulaulaman about #Pythagoras #Croton #HenrySwinburne #MagnaGrecia
Pythagoras spent the last years of his life at Metapontum. After his decease, the house he had dwelt in was converted into a temple of Ceres, and reforted to with the greatest veneration by the Metapontines, who were truly sensible of the advantages they had derived from his instructions(1)
This philosopher was one of the most exalted characters of antiquity; one of the few sages who did not confine their views to private and partial objects, but made their learning of use to nations at large, whom they instructed, enlightened and directed in the paths of moral virtue and real glory. Many ridiculous stories are related of his opinions and doctrines, which give us the idea of a visionary or impostor; but we should be cautious how we admit implicity anecdotes respecling the great men of distant ages, when we find them clash with what is allowed to have been their general line of conduct. Perhaps Pythagoras found it necessary, in order to captivate the veneration and confidence of a credulous superstitious people, that he should propagate strange and marvellous sigments, and thereby allure them to listen attentively to the lessons, and obey the injunctions of a lawgiver. He was the legislator, the reformer of Magna Graecia. To him and his disciples the little states that composed it owe a celebrity which they were not entitled to from extent of dominion or conquests. Their ruin may be attributed to the neglect of his precepts; or, indeed, in some shape to the very great successes attending his institutions, which rasfed those republics to such an uncommon pitch of prosperity, as intoxicated and finally corrupted their citizens.
(...)
Pythagoras, after his long peregrinations in search of knowledge, fixed his refidence in this place [Croton], which some authors think his native one, at least that of his parents, supposing him to have been born in the isle of Samos, and not at some town of that name in Italy. This incomparable sage spent the latter part of his life in training up disciples to the rigid exercise of sublime and moral virtue, and instructing the Crotoniates in the true arts of government, such as alone can insure happiness, glory, and independence.

(1) Some authors write that he died, and that the temple was dedicated at Croton.

(from Travels in the two Sicilies by Henry Swinburne - 1783-1790)

Note on the theory of hypergeometric functions

translation of #MaryFrancesWinston's paper by @ulaulaman from German #mathematics #Riemann
In the few last days I have search for more links about Mary Frances Winston, and I find the paper written by Mary when she was at Göttingen. So I try to translate(1) it using Google. I hope that this version is enough clear.

Riemann defined in its basic treatise the related $P$-functions first of all such as, whose exponents differ by integers, while the exponents are subject only to the condition that their sum is equal to 1: \[\alpha' + \alpha'' + \beta' + \beta'' + \gamma' + \gamma'' = 1 \qquad (1)\] and that none of the differences \[\pm (\alpha' - \alpha''), \; \pm (\beta' - \beta''), \; \pm (\gamma' - \gamma'')\] should be an integer. Meanwhile, the analytical definition provided herein is not the essence of the relationship. Rather all of the following developments about Riemann's related funcrions rest thereon, if only related functions should have the same monodromy. Now, Prof. Klein in his lectures about the hypergeometric function in the winter 1893-94, essentially noted that the latter is generally a result of the aforementioned analytical definition and that a special case exists, which is an exception. It is those exponents' system in which there exists the relation: \[\pm (\alpha' - \alpha'') \pm (\beta' - \beta'') \pm (\gamma' - \gamma'') = 2k + 1 \qquad (2)\] where $k$ is an arbitrary integer. Here are the P-functions: \[P \begin{pmatrix} 0 & \infty & 1 & \\ \alpha' + a' & \beta' + b' & \gamma' + c' & x \\ \alpha'' + a'' & \beta''+ b'' & \gamma'' + c'' & \end{pmatrix} \qquad (3)\] (where $a'$, $a''$, $b'$, $b''$, $c'$, $c''$ are integers of zero-sum) divide into two separate bands such that only the P-functions of the individual band are related to each other, i.e. have the same monodromy.
I was busy trying to find the analytical features of these two bands, and so the Riemann's initial analytical definition of the complete set, that fits all cases included in the Riemann treatise. My result is this:
It finds a relation instead of (2), so the left side of (1) breaks down in two integer triplets \[\alpha' + \beta' + \gamma' \qquad \text{and} \qquad \alpha'' + \beta'' + \gamma''\] On of such triplet (due to (1)) is necessarily positive, the other null or negative. We assume the definite expression for the triplet $(\alpha' + \beta' + \gamma')$ to be positive. The function (3) is given by the $P$-function if and only if the corresponding triplet \[\alpha' + a' + \beta' + b' + \gamma' + c'\] is also positive.
The proof is very simple. It is sufficient to establish the singular points $0$, $\infty$, $1$ corresponding fundamental branches of the P-function in the form of hypergeometric series and then to make the comparison. For example, for $x = 0$we have: \[P^{(\alpha')} = x^{\alpha'} \cdot (1-x)^{\gamma'} \cdot F (\alpha' + \beta' + \gamma', \alpha' + \beta'' + \gamma', 1 + \alpha' - \alpha'', x)\] \[P^{(\alpha'')} = x^{\alpha''} \cdot (1-x)^{\gamma''} \cdot F (\alpha'' + \beta' + \gamma'', \alpha'' + \beta'' + \gamma'', 1 + \alpha'' - \alpha', x)\] and here we see immediately that the one or other of the $F$-series breaks that occur (and therefore represents a rational integral function of $x$), according as \[(\alpha' + \beta' + \gamma') \qquad \text{or} \qquad (\alpha'' + \beta'' + \gamma'')\] It is a null or negative integer. This is the essence. Here I don't discuss further details.
Winston, F.M. (1895). Eine Bemerkung zur Theorie der hypergeometrischen Function, Mathematische Annalen, 46 (1) 160. DOI: 10.1007/BF02096208 (Göttinger Digitalisierungszentrum | Academic Search)
(1) It seems that an english version of the paper exists, but I cannot find it.