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    News Macchiarini - peer review cannot deal with lies

    In the decision to clear Macchiarini of misconduct (Swedish text), Karolinska states that the decision to operate on the first patient had been taken "after a clear process in health care including an evaluation by the ethics council of Karolinska Hospital". Macchiarini describes this process in...
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    News Macchiarini - peer review cannot deal with lies

    Macchiarini operated in violation of the Nuremberg Code and of the Declaration of Helsinki, principles of ethics for medical experiments on humans that were written down as a reaction to what had become known in the doctors' trials after WWII.
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    News Macchiarini - peer review cannot deal with lies

    But in this case, the record was not corrected from within science. Ethics committees gave the ok to Mengele-type experiments. Scientific peers (people in Italy, Delaere, colleagues at KI) tried to sound the alarm about discrepancies, there was an investigation, Gerdin reached clear conclusions...
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    Copper core copper coil?

    No difference for a stationary (DC) field.
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    Plagiarism in joint lab report

    He may have access to a stash of lab reports by older students? That was what I had, way way back. (I never copied though, just used them to learn.) It is not uncommon to find plagiarism in introduction and background. I react strongly in such cases, the student is in trouble when I see that...
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    A Advanced LIGO detection

    If the experiment is so advanced and difficult, why cannot LIGO arrange a webcast for the public? Our physics department wants to watch, we would like to invite students too.
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    News Macchiarini - peer review cannot deal with lies

    Thanks for reopening the thread. A very good summary by Gretchen Vogel was published in Science February 4. Since then the secretary general of the Nobel committee has resigned, because he assumed that he would be investigated by a special inquiry. That inquiry will be headed by Sten Heckscher...
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    News Macchiarini - peer review cannot deal with lies

    The whole system: peer review, collegiality, institutional checks and balances, ethics approval, science journalism, investigations into scientific misconduct. None of this worked. Extraordinary claims got published without even ordinary evidence.
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    News Macchiarini - peer review cannot deal with lies

    Maybe you saw the piece about this star surgeon's personal life in Vanity Fair, mythomaniac lies about getting married by the Pope, Putin and the Obamas attending. If it is too good to be true, it probably ain't true. The guy has a base in Sweden, at Karolinska Institutet, the home of the Nobel...
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    Depletion zone and current in forward-biased PN junction

    Do not post the same question twice!
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    How do i know what a function describe a wave?

    A constant wave can be written as a function of x-vt.
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    Depletion zone and current in forward-biased PN junction

    The drift current is caused by the built-in electric field over the depletion layer. It hardly changes with biasing.
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    Thermodynamics: Am i correct?

    No. As you suspected, I suppose. You can check your answers yourself: if you put back "t=20.81" in the first line of your equation, you will see that you are way off. From your second line, one can see that cooling and heating have a ratio of about 2:1 in temperature.
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    Interaction of light with a shockwave

    The shockwaves that one can see sometimes around fighter planes are due to water droplets. The other thing (as in Schlieren photography) is caused by variation in the refractive index with density.
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    How electrons show wave phenomenon within an atom?

    The p_x and p_y are standing waves, linear combinations of counterrotating spherical harmonics Y_{1,-1} and Y_{1,1}
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    Why are relays used in circuits?

    I invented this when I was 8 or 10 years old. With a Meccano electromagnet. Proudly showed it to my father. I was very disappointed when he said: "Ah, nice, you made a relay."
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    Telling a professor that other students are cheating

    It is not so easy to be creative for exams, retakes, and re-retakes on a number of courses each year. And it is bad for throughput. I want to teach, give my students the opportunity to learn something. I do not want to be police. I have reported egregious cases of cheating to the board of...
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    Solid State What would i need to begin in Solid State?

    One could start with the book by Turton. It has a pleasant level. Unfortunately, it is not entirely accurate. I made a list:
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    Refrigerator magnets with four poles apiece

    The Hallbach array, magnetic only on one side:
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    Magnet attraction reciprocity

    If you look at the Earth's field as produced by a current loop, you are looking on a scale where the field is inhomogeneous. Then there is a force between the two. But a current loop cannot produce a homogeneous field. (It may also help to remember that the gravitational attraction from an...
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    Magnet attraction reciprocity

    On the scale of the compass, the Earth's field is homogeneous. It only exerts a torque on the compass, otherwise there is no force between the two. (I am not entirely sure if this is relevant as an answer.)
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    What to do with Depleted Uranium?

    No need for lead. The paint already stops the alpha particles. The only risk of uranium is ingestion or inhalation of dust, and then the chemical toxicity is also a concern.
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    Private Thorium reactors?

    What jurisdiction? Here in Sweden, we are even obliged to pay for permission for our educational 35 kV/1mA x-ray tube.
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    Why is the band offset of an LED equal to the band gap?

    You are right, this is a dubious experiment. It is impossible to understand the results from physics alone. If you look at the diode equation, there is no threshold voltage.
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    Solving Physics Homework: Frequency Change

    Weird textbook. How can one learn any physics that way? The wording suggests a different mode of motion than for the case where this formula applies.
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    Solving Physics Homework: Frequency Change

    Units don't matter, just use the ratio. It is quite a difference if the mass is oscillating up and down on a string or whether the string is in a transverse oscillation without the mass moving. Different kinds of motion, different formulas apply.
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    Solving Physics Homework: Frequency Change

    The ratio between the masses is 60:38, so the ratio of frequencies is the square root of that. But what is this about: an oscillating mass on an elastic string or a vibrating cord under tension?
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    Whats the difference in glass electrons, and solid irons

    Or you could start looking at molecules, for example the energy levels of the H2 molecule. Then think about the energy levels of electrons in lithium clusters with increasing numbers of atoms. This leads to the tight-binding approximation of solids.
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    Wye Delta transformation

    You can probably figure out how to obtain the resistance between opposite corners when all edges of the cube have equal resistance, but how would you do the general cube? Other examples are messy nets of resistors, current sources, and voltage sources.
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    What type of solids have regular geometric pattern?

    Probably all solids are crystalline at thermal equilibrium. There does not seem to be a mathematical proof, but there are no known exceptions.
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    Number of photoelectrons liberated

    Of course the photoelectric current must depend on the color of the light. X-rays go straight through. Here is a plot of the spectral response of some alkali photocathodes (note the logarithmic scale): The best these optimized...
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    Number of photoelectrons liberated

    Silly problem. First of all because metallic surfaces are quite reflective (up to their plasma frequency). And of course there is also a wavelength-dependence in the probability of photoemission.
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    Magnetostatics: Finding B field using Amperes Circuital Law

    That is the problem of studying solutions. Unless you have reasons to expect the same problem, it is better to work the problem yourself.
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    Magnetostatics: Finding B field using Amperes Circuital Law

    It is just going from the current density j to the current I.
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    Magnetostatics: Finding B field using Amperes Circuital Law

    Inside and at R1 the current does not cause a field. At the outer radius R2, the field is equal to the field outside.
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    A Quantum entanglement by the means of beam splitters

    There is also this way: It uses the gamma photons from...
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    Wye Delta transformation

    The cube with resistors on all sides is an example.
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    Do X-rays' wavelength or frequency help them not excite electons....

    The material with the largest band gap is lithium fluoride, LiF, about 11 eV. Beyond that, everything absorbs any vacuum-UV or x-ray. If you need windows, people use thin foils of low-Z elements like beryllium or boron nitride or carbon.
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    Need help with generating a uniform weak magnetic field

    Helmholtz coils:
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    Traveling Tine Waves and Sound

    No. But you do not need to know the period of oscillation to say what distance the tine travels during one oscillation.
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    Traveling Tine Waves and Sound

    What distance does the tine travel in one period? How many periods in one minute?
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    Finding the total translational KE of 1kg of Neon

    Avoid calculating with numbers that are so large or small that you do not have any intuition for it. The basic number to remember is the gas constant, 8.3 joule per mole per kelvin. That way you can be more confident about your answer.
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    Finding the total translational KE of 1kg of Neon

    The translational kinetic energy per mole is 3/2 RT for any ideal gas. Neon is quite light, so there are many moles in a kilogram.
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    Do X-rays' wavelength or frequency help them not excite electons....

    You are asking now not about x-rays, but about visible light. Then the band gap is important. Graphite does not have a band gap and is therefor opaque. Diamond has a large band gap and is transparent for visible light.
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    Average number of photons in a cubic meter

    "The 3K background implies about 5.5 x 10^5 photons/liter." source:
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    Do X-rays' wavelength or frequency help them not excite electons....

    Metals are usually crystalline. It is difficult to make amorphous metals (metglass). They are not thermodynamically stable. None of this matters for the x-ray attenuation length, unless one looks at minute details.
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    Do X-rays' wavelength or frequency help them not excite electons....

    Nuclear motion does not matter at all for X-ray absorption. It is an atomic property. Band gaps only matter when one is doing high-resolution near-edge spectroscopy. Also melting only has an effect on minor details.
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    Lightbulb burnout

    Halogen bulbs have tungsten filaments. Anyway, the OP did not provide that much information about the bulb or about the point of failure, so we are just guessing.
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    Lightbulb burnout

    Lamps usually have a sticker saying the maximum allowed wattage. If you use bulbs with more power, you risk fire etc. I guess that you used a halogen light bulb. Those need to be handled with care, the glass surface must not have fingerprints.
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    Doubt on equipotential surfaces

    Indeed, Ohm's law applies. It is like at a body of water: the surface is level, unless there is a current.