It can be either TRUE or FALSE. FALSE, and a non-empty string is TRUE – with true/False exception:  A string containing a single zero is considered FALSE. TRUE – period, end of story. OR operator has lower precedence than assignment operators.

This is why you should NEVER use the OR operator without explicit parentheses around the expression where it is being used. Just something that will probably save time for many new developers: beware of interpreting FALSE and TRUE as integers. The problem here is, although array_search returns boolean false when it doesn’t find specific element, it is interpreted as zero when used as array index. Just a trap for young players who routinely work in both langauges. 00″ converts to boolean TRUE ! You may get such a string from your database, if you have columns of type DECIMAL or CURRENCY. In such cases you have to explicitly check if the value is !

0 or to explicitly convert the value to int also, not only to boolean. PHP does not break any rules with the values of true and false. The value false is not a constant for the number 0, it is a boolean value that indicates false. The value true is also not a constant for 1, it is a special boolean value that indicates true.


A boolean expresses a truth value. It does not say “a boolean expresses a 0 or 1”. It’s true that symbolic constants are specifically designed to always and only reference their constant value. But booleans are not symbolic constants, they are values. If you’re trying to add 2 boolean values you might have other problems in your application.

Port of San Diego lands large liner contract

A previous comment notes the trap you can fall into with this operator. I have often used it in situations where null or false indicate failure. The second allows for an alternative value if a falsy one is regarded as insufficient. All this presupposes that 0 is also an unacceptable value in the situation. Note you can also use the ‘! And non-integers are casted as if to bool, then NOT. Note: normal casting rules apply so a !

It is correct that TRUE or FALSE should not be used as constants for the numbers 0 and 1. But there may be times when it might be helpful to see the value of the Boolean as a 1 or 0. This will display the number 0 for false. For those wondering why the string “0” is falsy, consider that a good deal of input data is actually string-typed, even when it is semantically numeral. Consequently, PHP designers decided to treat 0 and “0” similarly, ie. TRUE for “true” “True” “TRUE” “Yes” “1” and so on. FALSE for “false” “0” “no” and so on.

NULL if string doesn’t represent a valid boolean. Dunno if someone else posted this solution already, but if not, here’s a useful and function to convert strings to strict booleans. 1 returns true, but you easily add some elseifs for other datatypes. Since I haven’t seen it posted. Here is a function that you can use if you have a need to force strict boolean values. Hopefully this will save someone some time from searching for similar. Actually from a complete noob point of view 0 resulting in false makes sense as many languages as I have been taught consider the value 1 as true and the value 0 as false a simple boolean value.

So lets says you think you set a variable to 0 and some how or another through your code this value has implicitly become and string instead of a int or boolean. Should PHP now consider it to evaluate to false. I wouldn’t think so but hey I’m a PHP noob so perhaps I’m missing why you would ever want a “0” string to evaluate to true. Just a side note, doesn’t really matters, the reason -1 is true and not false is because boolean type is treated as unsigned, so -1 would be for example, if it’s unsigned int32 translate to hex: 0xFFFFFFFF and back to decimal: 4294967295 which is non-zero.

PHP itself automatically makes a type cast or conversion for you, which may NOT be what you want or expect. In most cases, it’s better to provide functions that give your program the exact behavior you want. In other words, if we know what we want out of our program, we can create functions to accommodate. Here, we just wanted ‘manual control’ over numbers and strings, so that PHP doesn’t confuse us. Note that the symbolic constants TRUE and FALSE are treated differently. I was told that this is a feature, not a bug. No such tricks are required to get at the 1 that underlies true.

191, you can use a symbolic constant that makes sense, such as TOTAL_NATIONS. Exactly what php gets out of breaking this rule was not explained to me. Enter the characters you see below Sorry, we just need to make sure you’re not a robot. This article may be too technical for most readers to understand. Please help improve it to make it understandable to non-experts, without removing the technical details. A scalar field φ in a false vacuum.


Note that the energy E is higher than that in the true vacuum or ground state, but there is a barrier preventing the field from classically rolling down to the true vacuum. In quantum field theory, a false vacuum is a hypothetical vacuum that is somewhat, but not entirely, stable. It may last for a very long time in that state, and might eventually move to a more stable state. A false vacuum may only exist at a local minimum of energy and is therefore not stable, in contrast to a true vacuum, which exists at a global minimum and is stable. A false vacuum may be very long-lived, or metastable.

This section needs additional citations for verification. A vacuum or vacuum state is defined as a space with as little energy in it as possible. Despite the name the vacuum state still has quantum fields. A true vacuum is a global minimum of energy, and coincides with a local vacuum. It is possible that the process of removing the largest amount of energy and particles possible from a normal space results in a different configuration of quantum fields with a local minimum of energy. This local minimum is called a “false vacuum”.

Inside a Bitcoin Scam

In this case, there would be a barrier to entering the true vacuum. Perhaps the barrier is so high that it has never yet been overcome anywhere in the universe. A false vacuum is unstable due to the quantum tunnelling of instantons to lower energy states. Tunnelling can be caused by quantum fluctuations or the creation of high-energy particles.


The false vacuum is a local minimum, but not the lowest energy state. If the Standard Model is correct, the particles and forces we observe in our universe exist as they do because of underlying quantum fields. Diagram showing the Higgs boson and top quark masses, which could indicate whether our universe is stable, or a long-lived ‘bubble’. Many scientific models of the universe have included the possibility that it exists as a long-lived, but not completely stable, sector of space, which could potentially at some time be destroyed upon ‘toppling’ into a more stable vacuum state. A universe in a false vacuum state allows for the formation of a bubble of more stable “true vacuum” at any time or place.

This bubble expands outward at the speed of light. The Standard Model of particle physics opens the possibility of calculating, from the masses of the Higgs boson and the top quark, whether the universe’s present electroweak vacuum state is likely to be stable or merely long-lived. However, a definitive answer requires much more precise measurements of the top quark’s pole mass, and new physics beyond the Standard Model of Particle Physics could drastically change this picture. If measurements of these particles suggests that our universe lies within a false vacuum of this kind, then it would imply—more than likely in many billions of years—that it could cease to exist as we know it, if a true vacuum happened to nucleate. It would also have implications for other aspects of physics, and would suggest that the Higgs self-coupling λ and its βλ function could be very close to zero at the Planck scale, with “intriguing” implications, including for theories of gravity and Higgs-based inflation. A future electron-positron collider would be able to provide the precise measurements of the top quark needed for such calculations. Vacuum decay would be theoretically possible if our universe had a false vacuum in the first place, an issue that was highly theoretical and far from resolved in 1982.

The second special case is decay into a space of vanishing cosmological constant, the case that applies if we are now living in the debris of a false vacuum which decayed at some early cosmic epoch. This case presents us with less interesting physics and with fewer occasions for rhetorical excess than the preceding one. Such an event would be one possible doomsday event. It was used as a plot device in a science-fiction story in 1988 by Geoffrey A.

In theory, either high enough energy concentrations or random chance could trigger the tunneling needed to set this event in motion. However an immense number of ultra-high energy particles and events have occurred in the history of our universe, dwarfing by many orders of magnitude any events at human disposal. Joseph Lykken has said that study of the exact properties of the Higgs boson could shed light on the possibility of vacuum collapse. Therefore, after the bubble is nucleated, it quickly begins expanding at very nearly the speed of light. The excess energy contributes to the very large kinetic energy of the walls. If two bubbles are nucleated and they eventually collide, it is thought that particle production would occur where the walls collide. The tunnelling rate is increased by increasing the energy difference between the two vacua and decreased by increasing the height or width of the barrier.

The addition of gravity to the story leads to a considerably richer variety of phenomena. Alan Guth, in his original proposal for cosmic inflation, proposed that inflation could end through quantum mechanical bubble nucleation of the sort described above. The bubble’s effects would be expected to propagate across the universe at the speed of light from wherever it occurred. The top quark and Higgs boson masses and the stability of the electroweak vacuum”.

Lifetime and decay of excited vacuum states”. Vacuum Instability and Higgs Scalar Mass”. Consequences of Vacuum Instability in Quantum Field Theory”. If Higgs Boson Calculations Are Right, A Catastrophic ‘Bubble’ Could End Universe”. Article cites Fermilab’s Joseph Lykken: “The bubble forms through an unlikely quantum fluctuation, at a random time and place,” Lykken tells us.

Incomplete List

So in principle it could happen tomorrow, but then most likely in a very distant galaxy, so we are still safe for billions of years before it gets to us. The Probable Fate of the Standard Model”. Higgs boson and top quark masses as tests of electroweak vacuum stability”. Universe Has Finite Lifespan, Higgs Boson Calculations Suggest”.

Higgs Boson Will Destroy The Universe Eventually”. Higgs boson will aid in creation of the universe—and how it will end”. A Simple Motivated Completion of the Standard Model below the Planck Scale: Axions and Right-Handed Neutrinos”. Will our universe end in a ‘big slurp’?

The article quotes Fermilab’s Joseph Lykken: “he parameters for our universe, including the Higgs suggest that we’re just at the edge of stability, in a “metastable” state. Physicists have been contemplating such a possibility for more than 30 years. Tiny black holes could trigger collapse of universe—except that they don’t”. The End of the World:The Science and Ethics of Human Extinction. Fate of the false vacuum: Semiclassical theory”. The Inflationary Universe: A Possible Solution to the Horizon and Flatness Problems”. A New Inflationary Universe Scenario: A Possible Solution Of The Horizon, Flatness, Homogeneity, Isotropy And Primordial Monopole Problems”.

Cosmology For Grand Unified Theories With Radiatively Induced Symmetry Breaking”. Aspects of Symmetry: Selected Erice Lectures. National Portrait Gallery collections bring you face to face with America. Browse over 15,000 works from our collection. To search major collections from across the Smithsonian’s many museums, archives, libraries, and research units, please visit the Smithsonian’s Collections Search Center. Time Magazine Collection An extensive collection of cover art from Time magazine.

Presidential Portraits The nation’s only complete collection of presidential portraits outside the White House, this exhibition lies at the heart of the Portrait Gallery’s mission to tell the American story through the individuals who have shaped it. Miniatures Portrait miniatures are small, engaging, painted likenesses usually created as love tokens or personal mementoes. They were very popular during the eighteenth and early nineteenth centuries. By the 1840s, with the rise of photographic processes, small portraits were often made in that medium as well.

Daguerreotypes Highlights from the Gallery’s remarkable collection of daguerreotypes, the earliest practical form of photography. One Life: The Mask of Lincoln In the two-hundredth year since his birth, Abraham Lincoln remains as much a puzzle as he was to his contemporaries. That he came from nothing and was an obscure figure, almost to the moment of his nomination for the presidency, only adds to his mystery. First Ladies The National Portrait Gallery is well-known for our collection of presidential portraits, but we also have a comprehensive collection of the nation’s first ladies. Grant and Lee The rivalry between generals Ulysses S. Lee is one of the most memorable in American military history.

Lee was a polished and seemingly invincible Confederate commander who encountered Grant, a rough-hewn upstart, in the Virginia campaigns of 1864 and 1865. Women’s Suffrage The seed for the first Woman’s Rights Convention was planted in 1840, when Elizabeth Cady Stanton met Lucretia Mott at the World Anti-Slavery Convention in London, the conference that refused to seat Mott and other women delegates from America because of their sex. Investigate research options at the National Portrait Gallery. Their Privacy Statement applies to your use of this service. Solomon’s seal can be used both for food and for medicine.

Here’s an article outlining those uses. As you can see when you review the photos below of its life stages, the leaves look the same as Solomon’s seal. The biggest difference — which makes for easy identification — is the fact that False Solomon’s seal has flowers at the end of its stem. This is in contrast to Solomon’s seal which has flowers and berries along the underside of the stem. False Solomon’s seal has been used medicinally although it does not seem to be as well documented as Solomon’s seal. The berries of False Solomon’s seal are reportedly edible and also are red according to some other sources. I have not seen the red berries — probably because the wildlife eats them before they get to that stage.

This entry was posted in Plant comparisons. Thank you for the amazingly detailed pix and descriptions. I think this blog is one of the best-kept secrets on the internet. I’m sure it’s only a matter of time!

Thank you, this is a lovely blog, very useful. I have wanted to know which one I had, and with your details with pics, I know for sure that I have the true Solomon’s Seal. The detail of your pictures is wonderful! Showed me exactly what I needed to know. Thanks so much for the information and all the detail. I’ve passed it on to my daughter.

Cheapest possible decent bitcoin/litecoin/dogecoin mining rig? – [email protected], Boinc, and Coin Mining

I’ve been trying to get a decent description of the difference, and you made it complete and easy to remember. Thank you for filling in all of the important details that other sites seem to dismiss or completely ignore. I haven’t perused your site yet but if the rest is anything like this, I know I am going to be coming back often. I will contribute and support your work as well when I am able. As a scouting parent I used your site to prepare my presentation on plant identification for Boy Scouts adult training class. You are helping to keep this a fascinating topic.


12.7. Asymmetric Cryptography

Nature will bear the closest inspection. I found some false salomons seal today when I was gathering some rose hips and sage and yes the berries are red! I have had a strange thing happen in my garden. I planted Solomon’s Seal there a few years ago, but they have been replaced with the false ones.

I cannot figure out how this has happened. I have known the difference for years, would NEVER intentionally plant the false, as the ones I originally planted were rescued from an old crumbling foundation site. I’ve never heard of this before and have no idea how it might have happened. Thank you for the outstanding clarification on these two similar looking plants.

Doctoral Degree Programs

We have both growing here, but I was unsure what the true Solomon’s Seal was until, that is, now. You are correct that the false SS has red berries, at least in our area of Michigan. They are whitish with tiny red dots when young and mature to a solid somewhat translucent red. Thanks for the useful guide and clear photos. We have lots of Solomon’s Seal here in Finland.


I found your page while researching its uses by herbalist and foragers because I had been told to be careful. Is it a myth about their effects if in quantity? I do wonder who’s eaten how many and what the effect was. I frequently eat the False Solomon’s ripe red berries.

I eat about ten at a time being careful to spit out the hard seeds. I spit them where I think they might sprout. They have the flavor of slightly tart molasses and are quite good. I have never had any side effects, but never eat large quantities. I enjoy them for over a month in the fall until they are all eaten up.