"Items cannot be installed or removed until the package catalogue is repaired."
Item cannot be installed or removed until the package catalogue is repaired
A book suggests that we should not interchange "so" and "so that". "So" means "therefore", and "so that" means "in order that". However, it seems to me that in many cases they don't actually have a difference. For example:     Alice got up at 5:00 A.M., so that she could drive her son to school.   If I substitute "so that" with "so", this sentence presents the exact same causal relation to me:     Alice got up at 5:00 A.M., so she could drive her son to school.   I must have missed something here, since English is my second language. Could somebody explain the difference? Hash join between master/detail tables produces too-low cardinality estimate For $n$ a positive integer, let us write $\zeta_n = e^\frac{2 \pi i}{n}$, a primitive $n$th root of unity. It is clear that, if $m$ divides $n$, then we have an inclusion of cyclotomic fields $$ \mathbb{Q}(\zeta_m) \subseteq \mathbb{Q}(\zeta_n).$$ On the other hand, these inclusions are not always strict. For example, since $\zeta_3  = \frac{1+i \sqrt{3}}{2}$ and $\zeta_6 = \frac{-1 + i \sqrt{3}}{2}$, we have $$\mathbb{Q}(\zeta_3) = \mathbb{Q}(\zeta_6) = \mathbb{Q}(i\sqrt{3}).$$ Does this sort of thing happen infinitely often, or are there just some coincidences among small numbers? If this continues, is there some way to know when a particular inclusion of cyclotomic fields is strict? Imagine a black hole that is fast-approaching its final exponential throws of Hawking evaporation. Presumably, at all points in this end process there will remain a region that identifiably remains &quot;the black hole&quot; until the the very end, as opposed to huge swarm of fundamental particles that is being radiated out from it. As the mass of the black hole descends to that of individual particles, it would seem entirely feasible that the very last fermionic Hawking radiation event available to the almost-deceased black hole could leave it with an unbalanced charge, e.g. -1, and an unbalanced spin, say 1/2. It would also have some kind of mass of course, but that aspect of the final residue could be fine-tuned to any specific value by photon emissions of arbitrary frequencies. After photon emission mass trimming, the resulting black hole residuum would reach a point where it is no longer be able to evaporate into any known particle, because there is no longer any lower-mass option available to it for removing the -1 charge and 1/2 spin. The black hole residuum will at that point be stuck, so to speak, stuck with exact charge, spin, and mass features of an electron. And so my question: Is it an electron? And if so, by equivalence, is every electrons in the universe really just a particular type of black hole that cannot evaporate any further due to the constraints of charge and spin conservation? And if so, why are charge and spin so uniquely combined in such black hole remnants, so that e.g. a remnant of -1 charge and zero spin is not permitted, at least not commonly, and the mass is forced to a very specific associated level? Is there anything in the current understanding of general relativity that would explain such a curious set of restrictions on evaporation? The full generalization of this idea would of course be that all forms of black hole evaporation are ultimately constrained in ways that correspond exactly to the Standard Model, with free fundamental particles like electrons being the only stable end states of the evaporation process. The proton would be a fascinating example of an evaporation that remains incomplete in a more profound way, with the three quarks remaining incapable of isolated existence within spacetime. The strong force, from that perspective, would in some odd sense have to be a curious unbalanced remnant of those same deeper constraints on the overall gravitational evaporation process. This may all be tautological, too! That is, since Hawking radiation is guided by the particles possible, the constraints I just mentioned may be built-in and thus entirely trivial in nature. However, something deeper in the way they work together would seem... plausible, at least? If an electron is an unbalanced black hole, then the particles given off would also be black holes, and the overall process would be not one of just particle emission, but of how black holes split at low masses. Splitting with constraints imposed by the structure of spacetime itself would be a rather different way of looking at black hole evaporation, I suspect. (final note: This is just a passing thought that I've mulled over now and then through the years. Asking it was inspired by  by Ben Crowell. I should add that I doubt very seriously that that my wild speculations above have anything to do with Wheeler's concept of geons, though.) If my question gets migrated to another site, is it possible somehow to reverse it back to the original site? Where does de Broglie wavelength $\lambda=h/p$ for massive particles come from? I'm curious where the  $p=\frac{h}{\lambda}$ comes from?   I know that for light (which has no rest mass), the following is true:  $E=pc$ and $E=hf$  so,  $$pc=hf \Rightarrow p=\frac{hf}{c}=\frac{h}{\lambda}$$  But how is the expression $p=\frac{h}{\lambda}$ obtained for a massive particle where $E\neq pc$? I've read some people claim that the expression can be derived, and others saying it's an experimentally verified relationship. I am working on a problem and I am confused if exponents can be split up in the manner below.   $$x^{k+2} = x^{k+1}+x^{k+1} = 2x^{k+1} $$  I apologize if this is a simple question I tried to look up exponent rules but I couldn't find exponents + a number. Windows 10 won't accept Firefox as the default browser Ubuntu16.04 boots into initramfs Is it possible to have a rate of change of acceleration? I know this may seem a weird question, but it always bothers me. My physics book (Resnick,Halliday,Walker), and also various sites never say anything beyond acceleration.   But when a moving body is being acted by a variable force , its acceleration will definitely change: it will either increase or decrease. Then there will be rate of change of acceleration with respect to time. So, why don't books mention this? What is the cause for not measuring $\frac{d\vec{a}}{dt}$ ? If it exists, what is the use of it? How to apply for a UK standard visitor visa as a family? I am an Indian citizen residing in the United States. My wife and I are planning to travel to the UK for a week. We plan to apply for the UK standard visitor visa from the US. I was filling out the application and I have a few questions.   Travel History - The application asks for travel history to the United States, Canada, Australia and New Zealand. Considering that we're resident aliens in the United States, should we consider all the times we've traveled back to the US from India? Travel History - Should we also list out the times we've traveled to India from the US? Cost of the trip - Hypothetically if we plan to spend a total of ~4,000 USD on this trip, should I split up the cost and write down 2,000 USD on my application and 2,000 USD on my wife's application? Income - From what I've read on the forum, my wife must say that "someone else" i.e. me - is paying for her costs and mention my GWF number in the remarks on her application. Would that be sufficient considering that I'll be sending all income documents with my application? Savings - We have joint savings accounts. Should I mention the same amount on both our applications? Posting the documents - Is the up-to-date advice to send all documents in one packet? Or would sending them in separate packets at the same time be better? My thought was to annotate my wife's packet with my GWF number if we were to send them separately. Bank statements - We get e-statements. Would printing those out be enough? Why is accuracy not the best measure for assessing classification models? How can I tell how long (more or less) it will take me to complete a game? I'm going down my huge backlog of unplayed Steam games and I'm thinking the best way to tackle the list is to go through the shortest games first and then concentrate on the 20+ hour ones. I'm wondering if there's a website or something else that has an estimated amount of gameplay time for games.   Is there anything like that? What happens 'internally' on a unstable/overclocked/undervolted CPU? When you undervolt or overlock an CPU, when it passes a certain limit it starts to make the system unstable, reboot, etc. But these are the effects of it.  What I'm curious about is what happens on the CPU. What happens? It gives wrong answers to instructions? Bits on cache flip? I want to make a long shadow just like in this image.  I can create this shadow with shapes and by deleting the unwanted shadows after rasterizing the layer. But it's not very reusable. I can't resize the layer after rasterizing it.  Is there any easy way to make a long shadow like in the image below? No indent in the first paragraph in a section? Story where radically different cultures live together and are defined by rulesets, some choose not to see each other, a house is used as a spaceship I think this novel came out in the 2000s.  There are many cultures that live close together but are very different, for example some pretend to be pre-industrial.  One of the main characters is a youth who grew up in a pretend pre-industrial society and is now exploring the rest of the solar system? ring-world?   Each culture experiences their own reality that is defined by a ruleset.  One of the rulesets becomes aggressively self-propagating and this is the problem that drives the plot.  At some point a tumbling house, just a normal house, is used to travel across space. How to see if SkyDrive is still syncing in windows 8.1? Windows 8 displayed overlay icons on my SkyDrive files, so I could see which files are current and which are in sync.  After I upgraded to Windows 8.1 the files still sync, but I can't see if the files are current or not. The only way is to load a file, check for myself if the latest changes are there (if I remember them) and refresh until the file is synced. Which is a pain! The sync overlay does only show for files which modified locally and are waiting to upload, it does not show up for files which had been changed on the server (other computer) and are waiting to download!!  So how do I get the file sync Status on Windows 8.1? I used osm2pgsql to import data into my PostgreSQL database and it put gave me the following 4 tables, planet_osm_point, planet_osm_line, planet_osm_polygon and planet_osm_roads.   I have looked at the schema for osm2pgsql and inside the planet_osm_point table there is a column 'way' of type point. I tried to query it as an array like it says in the documentation here ():     It is possible to access the two component numbers of a point as   though the point were an array with indexes 0 and 1. For example, if   t.p is a point column then SELECT p[0] FROM t retrieves the X   coordinate and UPDATE t SET p[1] = ... changes the Y coordinate. In   the same way, a value of type box or lseg can be treated as an array   of two point values.   Anyone know the correct query the planet_osm tables from osm2pgsql based on long/lat? For example if I wanted to retrieve the information for Big Ben (London) I would query along the lines of:      SELECT * FROM planet_osm_point      WHERE ST_Y(ST_Transform(way, 4326)) = '-0.12'        AND ST_X(ST_Transform(way, 4326)) = '51.5';   There is no error message, it comes out with the table names, but no data is output either. (Its an empty table). What am I doing wrong here?  Perhaps it is too precise, i.e. there are no coordinates that match it exactly? Perhaps I need to try being more general, say 51 &lt; long &lt; 52 and -0.5 &lt; lat &lt; 0. Although this would throw back multiple results so would not be quite as accurate. My dconf/gsettings installation is broken. How can I fix it without Ubuntu reinstall? I run Ubuntu 12.04.1 LTS x64 in VirtualBox. After one very unfortunate misclick (reset saved state instead of load saved state) I got a very annoying problem.  Almost all applications (unity, synaptic, gedit, etc.) print on start:  Using the 'memory' GSettings backend.  Your settings will not be saved or shared with other applications.   And all GUI settings reset after reboot.   Another symptom:  $ GSETTINGS_BACKEND=dconf dconf-editor (dconf-editor:2353): GLib-GIO-WARNING **: Can't find module 'dconf' specified in GSETTINGS_BACKEND GLib-GIO-Message: Using the 'memory' GSettings backend.  Your settings will not be saved or shared with other applications   But /usr/lib/x86_64-linux-gnu/gio/modules/libdconfsettings.so is present.     What I tried (and it didn't help):   sudo apt-get install -f --reinstall  dconf-tools libdconf0 libdconf-dbus-1-0 dconf-service Build dconf-0.5 from sources and make install it Create empty user profile and start programs there   I have to keep current Ubuntu installation so a complete reinstall is not an option for me.   How can I fix it?