A lucid dream is a dream in which the sleeper is aware that he/she is dreaming. When the dreamer is lucid, they can actively participate in and often manipulate the imaginary experiences in the dream environment. Lucid dreams can be extremely real and vivid depending on a person’s level of self-awareness during the lucid dream. If this happens when you’re dreaming, imagine what you could do in your waking state.

We’ve been conditioned to believe that the external world is more real than the internal world. It’s not!

Part 2 of 4: Spin

Fundamental particles have a number of intrinsic properties, which are fixed, and the same for all members of a species. These include examples such as the rest mass of a particle, and its electric charge. Another intrinsic property is one called ’spin.’ The spin is a vector (of sorts), and its direction for particles of non-zero spin is an intrinsic degree of freedom.
Recall our discussion of the angular momentum in quantum mechanics, particularly the operators and their commutation relations, and the eigenvalue ladder. Spin is often described as being like the particles rotating around their axis; this fits only in that the previously mentioned mathematical description of quantized angular momentum also applies to spin, and that spin must be counted in the total angular momentum, with a few powerful differences; in analogy to the angular momentum numbers l and m (, ), we have s and m_s (, ). In one difference, the relationship between a charged particle’s spin and its magnetic moment involves a g-factor, and thus a gyromagnetic ratio, incompatible with classic physics theory (see here).

Another important difference is in the allowed values of s. As we found here, m ranges in integer steps from -l to l, so that for integer n; similarly, m_s ranges in integer steps from -s to s. When dealing with the eigenstates of angular momentum in position space, continuity in the azimuthal angular coordinate eliminated the half-integer values for l. Spin, however, is under no such restriction; s may be an integer or a half-integer.

I stated earlier that spin is an intrinsic property of a particle; in particular, the value of s is fixed for a given particle species. For example, electrons, protons, neutrons, and all flavors of quarks are all spin-½, which means s=½ for these particles. Photons are spin-1 (associated with polarization), while the delta baryons have a spin of 3/2. The hypothetical graviton, if it exists, must be spin-2 (as conservation of mass and momentum require that gravitational wave mechanicss by quadrupole wave mechanicss), and the hypothetical Higgs boson would be the only elementary particle with a spin of zero.

La fluorescenza è la propietà che hanno determinate sostanze, di riemettere a frequenza più bassa le radiazioni ricevute, in particolare di assorbire la luce ultravioletta ed emettere nello spettro del visibile.

Vediamo un esempio pratico:

prendiamo un foglio di carta formato A4 e scriviamo  con degli evidenziatori: giallo, verde, arancione e fucsia.

Illuminiamo il foglio con una lampada di Wood……ed ecco cosa vediamo:

gli evidenziatori che emettono nel visibile sono il giallo, il verde, e l’ arancione, il fucsia pochissimo….e perchè quest’ ultimo emette pochissmo??

Penso che ci siano 2 ipotesi (o più):

la prima è che ci sono pochissimi colori fluorescenti,

la seconda è che la mia lampada non ha la frequenza giusta per eccitare le sostanze presenti nel fucsia…

Sicuramente molti di voi, avranno notato però anche altro:

il foglio bianco emette nel blu…..questo è dato dalla presenza nel foglio di determinate sostanze, chiamate sbiancanti ottici, che sono presenti anche nei detersivi per il bucato, e che hanno il compito di donare al foglio o ai capi, quello che viene definito “più bianco non si può”.

In assenza di queste sostanze i fogli ed i capi apparirebbero gialli, anche se appena lavati, cosa non molto gradevole a vedersi.

Ora però proviamo ad eliminare il blu del foglio per concentrarci sugli evidenziatori, utilizzando un programma di fotoritocco eliminiamo la componente del colore che non ci interessa.

Ecco il risultato:

ora il fucsia si vede leggermente di più, il giallo è distinguibile dal verde,  l’ arancione è  arancione e non rosa come sembrava.

Infine la prova del 9: poniamo un filtro taglia UV (non fa passare UV), per vedere cosa succede:

Si vede chiaramente che l’ emissione, dei colori al di sotto del filtro è molto minore rispetto ai circostanti.

La caratteristica della fluorescenza viene spesso usata in ambito bio-medico, ad esempio quando vengono eseguite biopsie e quindi preparati istologici, in cui si mettono in evidenza particolari antigeni tramite anticorpi “coniugati” con particolari sostanze fluorescenti: i fluorocromi.

Successivamente si osserva al microscopio illuminando il preparato in diascopia (dall’ alto), con luce UV,  saranno quindi visibili solo le porzioni che contengo gli antigeni riconsciuti dagli anticorpi.

Nella foto seguente, un glomerulo renale, in caso di LES.

Da: www.patologinfiore.it

Altri esempi in ambito bio-medico, possono essere le proteine denaturate, che sono autofluorescenti, oppure i tessuti che sono stati sottoposti a livelli glicemici elevati per lunghi periodi, anch’ essi autofluorescenti.

Alla prossima.

Here is an example:

take a sheet of A4 paper and write with highlighters: yellow, green, orange and fuchsia. 

Enlighten the sheet with a dark light …… and that’s what we see:

the markers that emit in the visible are yellow, green, and ‘orange, fuchsia very little …. and why’ s very little?

I think there are 2 cases (or more):

The first is that there are very few fluorescent colors,

the second is that my lamp does not have the right frequency to excite the substances in fuchsia …

Surely many of you have noticed but even more:

emits a clean sheet in the blue ….. this is the presence in the form of certain substances, called optical brighteners, which are also present in laundry detergents, which are responsible for donating the sheet or to the dress, that which is defined as “more white you can not.”

In the absence of these sheets and dress appear yellow, even if just washed but not very pleasant to see.

But now we try to eliminate the blue sheet to focus on the markers, using a photo editing program to remove part of the color that we are not interested.

Here’s the result:

fuchsia now you see a little more, the yellow is distinguishable from the green, the ‘orange is orange, not pink as it seemed.

Finally, the proof of 9: we put a UV filter size (it does not pass UV), to see what happens:

It is clear that the issue, the colors below the filter is much smaller than the surrounding.

The characteristic of fluorescence is often used in bio-medical, for example, when biopsies are performed and then histological preparations, which highlight specific antigens using antibodies “married” with special fluorescent substances: the fluorochromes.

Subsequently observed under the microscope illuminating the preparation in diascopia (from ‘high), with UV light, will be visible only the portions that contain antigens recognized by antibodies.

In the photo below, a renal glomeruli, in the case of LES. 

Other  examples in bio-medical, may be the denatured proteins, which are autofluorescence, or tissues that have been subjected to high blood sugar levels for long periods, also they autofluorescence.

To the next.

Nuclear fusion power project to start in 2018: official
Scientists capture the first image of memories being made
World’s fastest and most sensitive astronomical camera
3D printing for new tissues and organs
Physicists create ‘dark hole for sound’
Most powerful ’sound laser’ to shake up acoustics

Addendum: Today, 386 years ago (1623), french mathematician and physicist Blaise Pascal was born.

Here’s a link to an article by Paul Quincey on CSI Online:

Why Quantum Mechanics is Not so Weird After All