Computation of a homotopy colimit of pro-spectra

Question: Suppose $E\simeq\text{hocolim}_iE_i$ is a filtered homotopy colimit. Suppose $X=\{X_j\}_j$ is a pro-space (assume some finiteness conditions on the spaces or spectra if you have to...for example, assume $X_i$ are simplicial sets with finitely many simplicies in each degree). Is it true that in the $\infty$-category of pro-spectra, we have $\text{hocolim}^{pro}_i\{E_i\wedge X_j\}_j\simeq \{\text{hocolim}_i(E_i\wedge X_j)\}_j$? More generally, is it true that if $E_i$ are pro-spectra with some mild finiteness condition and all indexed by the same cofiltered diagram, then I can compute their homotopy colimit degreewise?
Answer: This is not true, unfortunately. Here's an example.
Let $E_i$ be the directed system
$$
\DeclareMathOperator{\hocolim}{hocolim}
\DeclareMathOperator{\holim}{holim}
S^0 \to S^0 \vee S^1 \to S^0 \vee S^1 \vee S^2 \to \dots
$$
of wedge inclusions, and let $X_j$ be the inverse system
$$
S^0 \leftarrow S^0 \vee S^1 \leftarrow S^0 \vee S^1 \vee S^2 \leftarrow \dots
$$
of projections. Both are systems of objects of finite type, and both the homotopy limit and homotopy colimit are also of finite type.
We also have a natural isomorphism
$$
Map(E_i \wedge X_j, F) \cong \bigoplus_{k=0}^i \bigoplus_{l = 0}^j Map(S^{i+j}, F).
$$
Let $F$ be any spectrum, viewed as a constant pro-object. Then we can show that the two spectra you describe are different by calculating homotopy classes of maps out to $F$:
$$
\begin{align*}
Map_{pro}(\{\hocolim_i(E_i\wedge X_j)\}_j, F) &= \hocolim_j \holim_i Map(E_i \wedge X_j, F)\\
Map_{pro}(\hocolim^{pro}_i\{E_i\wedge X_j\}_j, F) &= \holim_i \hocolim_j Map(E_i \wedge X_j, F)
\end{align*}
$$
Thus, we have isomorphisms
$$
\begin{align*}
[\{\hocolim_i(E_i\wedge X_j)\}_j, F]_{pro} &= \bigoplus_l \prod_k  \pi_{k+l}(F)\\
[\hocolim^{pro}_i\{E_i\wedge X_j\}_j, F]_{pro} &= \prod_k \bigoplus_l \pi_{k+l}(F)
\end{align*}
$$
In particular, the natural map from the top to the bottom is not an isomorphism unless the homotopy groups of $F$ are zero above a certain degree.
As you can see, finiteness properties on the $E_i$ or $X_j$ don't buy you what you need. If you are taking a hocolim over a finite diagram instead (pushouts, finite wedges, things built from those by finitely many steps), then the fact that the category of pro-spectra is stable allows you to move the homotopy colimit inside the inverse system.
Comment: @user108170, unfortunately that's not true either. If you let $M = \Bbb{RP}^2$ viewed as a based space, replace $S^n$ with $S^n \wedge M$ throughout, and take $F = \prod_{i=0}^\infty H\Bbb Z/2$, then you can get a contradiction satisfying those conditions too.
Comment: (There are some applications that localize the category of pro-spectra to ensure that they have convergent Postnikov towers. In _that_ case there might be some assumptions that might work for you.)
Comment: Basically, the situation is that the $E_i$ are cohomologically Bousfield localized with respect to $H\mathbb{Z}/p$, and $X$ is $p$-profinite, meaning that it is a pro-object in the category of $p$-finite spaces. The final weak equivalence that I want may also be after cohomologically Bousfield localizing with respect to $H\mathbb{Z}/p$.


Backing up contacts, call log, SMS/MMS and gallery via adb?

Question: I have an old Nexus 5 running KitKat and I need to back up its contacts, call log, SMS and gallery photos via adb - not through an app. After that I need to upgrade the phone to 7.1.1 and restore these backups. I have no idea how to do this but I understand SMS at least is not covered by adb backup. What do I need to do to change this?
Answer: If you have a Google Account connected to your Android Device, then Contacts are automatically backed up. As far as the Call Log, that would be  info that your carrier can provide. The same is for SMS, when you boot your phone, the server normally updates your sms/ call log info, so calling the carrier would be a good idea. There is an App on most Android phones, called Picassa, that comes with the phone. You could try connecting your Google Account to Picassa, and setting the App to  upload your photos to it.
     I'm not a developer, but I own a phone with the same OS, I hope these suggestions help you. :)


What GIS editors work with GIS data that is stored in SQL-Server

Question: If I store my vector GIS data in SQL-Server, what editors can I use to edit the GIS data?
Answer: Have you seen the SQL Spatial Tools from Sharp GIS? Or did you have more advanced requirements?
Answer: Manifold will directly read and write SQL Server spatial data. I assume you are using 2008, but if not, Manifold will also let you use SQL 2005 (Geometries are varbinary(MAX) not SQLGeometry / SQLGeography in that case). They have a free CLR add-in that provides spatial indexing for 2005.
It supports multi-users, conflict resolution, etc.
We use it internally and I know many others who do too. It's stable and robust.
Answer: The development build of GDAL includes an OGR driver for SQL Server:
http://www.gdal.org/ogr/drv_mssqlspatial.html
Answer: Your open-source (free) alternatives are a bit limited, you might be able to put something together with GeoServer (http://docs.geoserver.org/stable/en/user/data/index.html) as a viewer at least, if a web app is your intent. However many commercial GIS environments support SQL Server; a list of 'spatial partners' can be found here
http://www.microsoft.com/sqlserver/2008/en/us/spatial-partners.aspx
Answer: TatukGIS Editor will edit geospatial data in most all spatial databases - Sql Server, Oracle, SDE, PostGIS, pGeodb,etc.
Also, the new Fgis, based on tatukgis editor, can edit/view Sql Server Spatial.
It is only $99.
http://fgis.tatukgisconsulting.com/
Answer: QGIS version 1.8 now has native (not using OGR) read/write/edit support for MS SQL 2008/2012

This will work on Windows, Linux, OS X.  Although Linux and OS X require some more setup then what windows does due to the Qt ODBC driver.
Answer: You can try with AutoCAD Map (FDO). I use it for editing SQL Server 2008 spatial data. Currently I cant remember any other good editor for SQL Server spatial data editing.
Answer: I have used Manifold to edit SQL data, but it seems it actually grabs the table and brings the data into Manifold for edit (maybe stores it in memory?). When you save, it seems to write the whole table back to SQL.
I have used TatukGIS's Editor too. This does a very good job of just editing the selected records or writing the new records back to SQL. But I find the editing tools a little clunky.
I have also tried ArcGIS 10 via ArcSDE. Yes, you can tell ArcGIS to write the data as SQL Spatial format. But it wraps a lot of other tables around the data. PLUS, if you have a native SQL Spatial table, ArcGIS can not access it or edit it. It must run through Esri's GeoDatabase to be available to ArcGIS.
I would like to know if Quantum GIS built with the new OGR would allow for editing SQL Spatial. That would be a great solution.
Comment: Yeah QGIS will let you edit spatial data in SQL 2008 see: http://woostuff.wordpress.com/2011/06/07/opening-ms-sql-server-2008-spatial-tables-in-qgis-correctly/
Comment: small clarification about Manifold, while it does grab the table and bring it into memory, it retains an open link to the database as well, so any updates are persisted immediately, rather than writing the whole table back. For larger datasets, you can set it up with SQL Server to only grab a bounding box of data rather than the whole dataset.
Comment: Not completely correct. ArcGIS 10 introduced the Query Layer, where you can (only read) almost every native spatial database type directly without SDE or enterprise geodatabase. But you are right, when it comes to editing, you need at least ArcEditor and SDE. In 10.1 database connection mainly uses th new query layer approach. Seems that ESRI realized, that their users don't want to extra pay for database access anymore.
Answer: To my opinion Manifold GIS is the most practicable solution for direct editing of SQL-Server geometries.  Unfortunately they are now announcing a new Version for more than 18 months.  So it is not really clear if you investment will be sustainable. But for the moment manifold is excellent.
if you want to do some coding mapdotnet.com offers read-write connectors to SQL-Server
Answer: Intergraph's GeoMedia suite of products support SQL Server databases. Since recently i.e., from January 2012, SQL Server 2008 spatial enhancements are also supported.
Answer: MapInfo Professional has been able to read and write data stored in a SQL Server 2008 database. This support has been included in MapInfo Professional since v10.0.
No middleware required, except an extra table in the database describing to MapInfo Pro how to  read the data and how to display the data on a map (styles and so)
Comment: With MapInfo Professional 11.5 support for SQL Server 2012 has been added
Answer: It is possible to create and edit simple features using a web OpenLayers front-end and passing WKT directly into SQL Server geometry fields.
Answer: You can also set ArcSDE to store geometries using Microsoft's CLR Spatial types (SqlGeometry/SqlGeography) instead on ESRI's binary format.  Then you could use ArcGIS Desktop to edit the vector data.
Answer: You can edit SQL Server vector geometry data in ArcView without SDE using the "GISquirrel" extension (formerly known as ArcSquirrel). See www.gisquirrel.com
Answer: AFAIK, none support direct edition of SQL SERVER 2008 spatial data.
With ArcSDE installed in your DB you can edit your data in ArcGIS.
Perhaps someone with more sqlserver experience might give you better hints.
George
Comment: what do you mean by "none support direct edition"? I guess this list here kind of proves that there is a number of tools that do support direct editing of SQL Server 2008 spatial data. But maybe I misunderstand what you are saying?
Comment: -1 as this is incorrect.  As Peter said, this list proves otherwise.


Density calculation in K Means clustering

Question: With the K Clusters generated using K Means Clustering, how do we calculate the density of each cluster? Is there any formula for it?
Comment: How do you define 'density'?
Comment: K-means is not a density based algorithm. As the clusters usually are not at all uniform in density, any such number would have a limited use.
Comment: K-means aims to minimize within-cluster sum of squares, because when the centres get stabilized, they are the means, and a mean is the locus of minimal sum of squred deviations from it. So, the most natural (non)density measure is the within cluster SS or SS/n (the variance). (The problem with K-means, though, is that it is prone to local optimum results, being very dependent on choice of initial centres.)
Comment: Do you want to just evaluate the quality of clusters using some sort of density metric, or do you actually want to make the clusters based on that density?
Answer: One possible method:

For each data point, calculate its distance from each of the
centroids. Let x be a coordinate vector pointing to the data point and c
be a coordinate vector pointing to some centroid. Then the distance to the centroid can
be defined as:   $d = \sqrt{(\vec{x}-\vec{c})'*(\vec{x}-\vec{c}) }$
For each data point, identify the centroid(s) with the smallest distance value ($d$). If there are $m$ such centroids, give a score of $\frac{1}{m}$ to each centroid (typically one would expect $m=1$).
Accumulate the total score for each centroid across all of the data points. The total score can be considered the "density" of the cluster as it conveys the number of data points within the "region of influence" of the centroid.

A more sophisticated approach might be to also weight the scores based on some decreasing function of the $d$ value, giving a higher density score for points that are very close to the centroid.
For comparison between datasets, you could also scale the final density scores by dividing each centroid's score by the total across all centroids. Then each score would be a value between 0 and 1.
Comment: @Marcin I wish to use the density metric to evaluate the quality of clustering. And I wish to know, if we could calculate density of each cluster in K Means clustering or not..
Comment: @WillTowns Thanks for your method.  I think I could use that. Thanks a lot.
Answer: K-Means tries to minimize the sum of square distances of the points to their cluster center. After running K-Means, you can compute some statistics that will help you measure the "density" of the clustering.
In R, these statistics are included in the generated clustering object, but you can also compute them by yourself. The "density" or "goodness" is expressed by the ratio of the "betweenss" - the sum of squares between the clusters - and the "totalss" which is the total sum of squares for the entire collection. The higher the ratio, the better. Here is a quick example in R:
<code>data(iris)
tbl = iris[,1:4]
clust=kmeans(tbl,2)
cat("The clustering 'density' is", clust$betweenss / clust$totss," the higher the better\n")

#This is how you can compute the withinss, betweenss and totss by yourself
withinss = 0
for (i in 1:length(clust$size))
{
  clust_i = tbl[which(clust$cluster==i),]
  withinss = withinss+sum((clust_i-matrix(data=clust$centers[i,],ncol=ncol(clust_i), nrow=nrow(clust_i),byrow = TRUE))^2)
}

totss = sum(rowSums((scale(tbl,scale=FALSE))^2))
betweenss = totss-withinss
score = betweenss/totss

cat("The clustering 'density' is", score," the higher the better\n")

</code>


Sharps at the start of a score

Question: I'm having difficulty identifying and playing the sharps which are C# , D# , F# and G# . Do the sharps apply to all the bars ?
Answer: Yes they do because they are the key signature of a piece. The key signature tells you what key you are in and what notes to expect. Since you are in the key of E major, you will most likely use the notes E, F#, G#, A, B, C#, D# which the four sharps represent. Those are the notes you should use unless a different accidental is applied to a note.
Comment: I'd just add that they apply to all octaves covered by that stave. If the note is a ledger line below, or two ledger lines above the stave, it's still C♯.
Comment: Sounds more like C#m to me, from this snippet. Same sharps, though.
Answer: The #### circled in red in your answer are the key signature. YOu can read this as "four sharps", that stand for E Major (or C# minor). Basically all F C G D in the score are sharp, no matter in which octave. The simplest case is No Sharps/No flats (C Major / A Minor), in that case all notes are natural.
Comment: I would add that all F C G and D's are sharp unless otherwise indicated by the natural symbol next to the note.
Answer: You can find a list of Major Scales in any basic music theory book . Also look on the web for a list of scales .Each scale has a note name.That is the keynote of the scale. A short trick to help you with sharp keys is to look at the last sharp symbol .In the diagram above the four sharps are shown in a red circle. The last sharp is on the D. So go up one position and you will be on the keynote which is E. On any sharp key take the last sharp and go up one position for the keynote.
  So what do you do with that?  Just play a major scale starting on that keynote and practise that a few times  before you play the music .Use it as a reminder. Its there to help you and not to confuse you .
 There is an opposite trick for flat keys . Pick the next to last flat. That is your keynote .
Dont worry about Minor Keys yet as any extra sharps or flats will be written in the bar when they are needed.
But All the Bars are affected by the Key Signature .
 The rules about Keys  are there to help you .

Sharps at the start of a score


How to create a private exit node?

Question: I would like to create an private exit node that only I have access, it will be set on my personal computer, then plan to create "exit node" to relatives who live USA and France so I can have a fully encrypted system for use with a vpn without worrying if the site is http or https. It is possible to do or is it safe to create this kind of "private exit node" with only people in my circle of trust, to use database and sensitive data sites?
Comment: It doesn't sound like you need Tor for this. Just set your PC as a VPN server and limit users by login.
Comment: Since you won't be getting any anonymity out of this (what Tor is designed for) you're just introducing needless latency into your connections. A VPN or encrypted proxy will provide you with what you want.
Comment: For all intents and purposes, you can achieve the same result using [VPN Over Tor](https://exposingtheinvisible.org/en/guides/vpn-over-tor/).
Answer: Tor does not have a concept of exit nodes that only you can use.
The routing protocol allows for it, but there is no support in Tor or its directory layer for what you ask.
Answer: It is possible to setup non-published (private) exit node, but managing it is inconvenient. The node should be added to the client manually via ControlPort, using router descriptor, and the circuit over that Exit Node need to be build also manually.
The algorithm in general is as follows. On server:

Configure Tor exit node as per official instructions
Add the following to the configuration file to make it private: PublishServerDescriptor 0, and also activate DirPort on localhost: DirPort 127.0.0.1:9093 NoAdvertise
Run Tor Exit node, grab its descriptor: curl http://127.0.0.1:9093/tor/server/authority, save it somewhere
Your Exit desciptor contains fingerprint line with the fingerprint separated with spaces. Remove all spaces (make it 40 symbol string). That's the fingerprint of Exit Node

On client:

Set UseMicrodescriptors 0 (microdescriptors can't be easily managed outside of consensus, we'll work with full descriptors), activate ControlPort
Start Tor client
Connect to ControlPort, authenticate with AUTHENTICATE command (check controlspec)
Add Exit descriptor by running: +POSTDESCRIPTOR cache=yes purpose=controller, paste the descriptor, end with . (dot)
Check connected circuits: GETINFO circuit-status. You should see circuits in the form like this:

4 BUILT $7A35EE286D3FDBB272F39D4916F0879EE12EA581~TK998,$40E82B3E7B9167BC2B8B8B94F8CC4F48317BDAC6~tirz,$07F0E652E4CCB0A0F1E88D0046ECB322E6318C86~RiggsOceanlock BUILD_FLAGS=IS_INTERNAL,NEED_CAPACITY,NEED_UPTIME PURPOSE=GENERAL TIME_CREATED=2022-07-12T20:27:24.770156

This is a 3-hop circuit: 7A35EE286D3FDBB272F39D4916F0879EE12EA581, 40E82B3E7B9167BC2B8B8B94F8CC4F48317BDAC6,07F0E652E4CCB0A0F1E88D0046ECB322E6318C86

Grab any 3-hop circuit and replace the latest hop with the Fingerprint of your Exit Node.
Run EXTENDCIRCUIT 0 7A35EE286D3FDBB272F39D4916F0879EE12EA581,40E82B3E7B9167BC2B8B8B94F8CC4F48317BDAC6,YOURFINGERPRINTHERE
Now you can use your private Exit Node, however to reliably use it, you'll need to map exact IP addresses/domains to it. In ControlPort: ADDRMAP ifconfig.co ifconfig.co.YOURFINGERPRINTHERE.exit

Now ifconfig.co would open via your private Exit Node.
This all could be automated with stem custom path selection.

How to create a private exit node?


Moksha as continuous Samadhi?

Question: Is there anything in any scripture that you know of that would say or imply moksha can be described as permanent samadhi on brahman or on parabrahman - as continuous abiding in/as Brahman? Or any other type of permanent samadhi?
Comment: Samadhi has savikalpa samadhi nirvikalpa samadhi. You come back to world from savikalpa. Nirvikalpa you abide in self. No return.
Comment: @PrabrahmanJyoti people come back from Nirvikalpa Samadhi, for eg: Ramakrishna Paramahamsa
Comment: You can try searching in commentaries on yoga-sutras. There are mentions of two types of samadhi as means of liberation.
Comment: The fact that people come back from a samadhi doesn't necessarily mean that those at moksha do so. Also, those who have achieved moksha may go deeper into it at dedicated times. Im not saying thats right, just a possibility for the above
Comment: @MrGreenGold yes as I wrote below: a "state of quietude, in which, identified with Brahman, he has constant enjoyment of the Bliss Absolute, the One without a second." sounds a lot like samadhi. But idk.
Comment: That is the entire purport of the Upanishads...It is said everywhere in the Upanishads. You might try to do a search on this forum. This questions and similar questions has been asked previously.
Comment: @SwamiVishwananda thanks glad to hear that. In the answer below and its comments one knowledgeable person is saying otherwise.
Answer: Moksha is not continuous Samadhi. A person who has realized Brahman in Samadhi stays in that state of identification with Brahman regardless of what he does. It does not matter whether he is in samadhi or not.

To the sage who has realized Brahman, the mind, which is the cause of
unreal fancies, becomes perfectly tranquil. This verily is his state
of quietude, in which, identified with Brahman, he has constant
enjoyment of the Bliss Absolute, the One without a second.

Vivekacudamani 526

To the man who has realized his own nature, and drinks the undiluted
bliss of the Self, there is nothing more exhilarating than the
quietude that comes of a state of desireless.

Vivekacudamani 527

The illumined sage, whose only pleasure is in the Self, ever lives at
ease, whether going or staying, sitting or lying, or in any other
condition.

Vivekacudamani 528

The noble soul who has perfectly realized the Truth, and whose
mind-functions meet with no obstruction, no more depends upon
conditions of place, time, posture, direction, moral disciplines,
objects of meditation and so forth. What regulative conditions can
there be in knowing one's own Self?

Vivekacudamani 529
Comment: Pradip I think you are wrong here, the constant experience of bliss here is Samadhi. There are two different types Savikalpa and Nirvikalpa. People who have realised will always be in Savikalpa Samadhi, that is why they are always blissful, that's the mechanism IMHO.
Comment: Thanks for the great reply and verses .  However, a "state of quietude, in which, identified with Brahman, he has constant enjoyment of the Bliss Absolute, the One without a second." **sounds a lot like samadhi**. But idk. Any thoughts about that?
Comment: @MrGreenGold,@Al Brown, Yes, identification with Brahman has features that are common with Samadhi. However, this experience is not samadhi. In Samadhi the entire mind is withdrawn from the world and focused on an object. In the state of Samadhi it is not possible to teach while Ramana Maharsi or Sri Ramakrishna did teach. As regards Savikalpa Samadhi it is true that such a person will continue to have an experience of divine forms but such a person will not always withdraw his mind from the world.
Comment: In samadhi there is no mind. Mindless state. Mind doesn't function.  There's no focus. No concentration nothing. Mind freezes. The complete emptiness where the state cannot be described its samadhi. Remember as long as you describe experiences of dhyan the mind is in operation.  In samadhi there's no mind.

Moksha as continuous Samadhi?


AD Dynamic DNS not working with Linux IPv6

Question: I have an AD DNS/DHCP enabled server. I have mixed Windows and Linux machines/servers. IPv4 is working great with DNS/DHCP, even for the Linux systems. IPv6 is working great except that it won't generate a DHCP lease or DNS entry. If static IPv6 AAAA records are used, I can use my RAS server, browse IPv6 websites, and connect to any machine, even across the internet.
What I can do with IPv6: I can get a DHCP IP address on any system, Linux or Windows. I have fd0a:fb5*:bdc*:0::x as my /64 prefix and it works great; ALL systems have an address with this prefix. can ping, DNS lookup, and connect to Windows systems and websites perfectly. The only issue I have is that IPv6 leases and DNS AAAA records are not added/updated dynamically for the Linux systems. A records and IPv4 leases all work fine.
I have added a dedicated user called DHCPDynUpd and given added it to the DNSUpdateProxy group. I then assigned a password that never expires and denied logon hours and disallowed signing into any machine. In the DHCP settings on IPv4 and IPv6 I signed that user into the DNS dynamic update registration. Then I set the IPv4 settings to "Dynamically update DNS A and PTR records for DHCP clients that do not request updates (for example, clients running Windows NT 4.0)"; this is not a setting under IPv6. Then I set them to both dynamically update A/AAAA and PTR records.
I know the user is working or the DDNS updates for IPv4 wouldn't work...
Also on the Linux machines I ensured that they are set to a FQDN in the hostname file and that they are broadcasting the hostname/domain in the dhclient config.
Machines used:
⠀Windows Server 2012R1,
⠀Fedora 20 VPN/mail/web servers,
⠀Windows 8.1
Some resources I found and followed to the best of my ability:

Windows Server DNS with non-Windows (Linux, Mac) Computers
Register A records for my Linux box on my Windows 2008 DNS/DHCP server
https://social.technet.microsoft.com/Forums/windowsserver/en-US/535e7718-a0e3-41d2-b2c1-961f2d9a0dbd/linux-clients-are-not-registered-in-dns-using-ms-2008-r2-dhcp-and-dns-servers?forum=winserverNIS
Answer: Turns out I didn't have a good understanding of Stateful and Stateless IPv6. I followed this article and it now generates leases and the corresponding DNS records.
https://social.technet.microsoft.com/Forums/windowsserver/en-US/0ff3fbcd-de53-47ca-9027-9a6b8e27509c/how-to-configure-dhcp-ipv6-stateful-configuration-using-windows-server-2008?forum=winserverNIS


Prounouncing the combination "-cy-"

Question: Is there any word in the English language that contains the letter combination "-cy-" and pronounced with a hard 'c'?
I find it strange that all the common use words are pronounced with a soft 'c' if the 'c' is followed by a 'y', considering that Middle English pronounced the combination as 'ky'.
Comment: "... considering that Middle English pronounced the combination as 'ky'" -- source?.
Answer: Here's a (most likely incomplete) list of all the words I found where cy has a hard c:

Baccy is pronounced /ˈbæki/.
Choccy is pronounced /ˈtʃɒki/.
Laccy is pronounced /ˈlaki/.
Leccy is pronounced /ˈlɛki/.
Piccy is pronounced /ˈpɪki/.
Placcy is pronounced /ˈplaki/.
Talcy is pronounced /ˈtalki/ or /ˈtælki/.
Tobaccy is pronounced /təˈbaki/.

All of these words (except for "talcy") seem to have been formed within the past 200 years. Some words that would have been spelled like this end up with a k added, such as colicky.
Comment: Other than *talcy* all have a double-c, though.
Comment: They necessarily have a *k* added on because otherwise the *c* would be soft, a double-c is not.

Prounouncing the combination "-cy-"


Requirements for negative binomial regression

Question: In my study, I experiment with fixed and mixed effects negative binomial regression to my data (in R) as the response variable is a count variable. Normally I should use Poisson regression but (and here I have doubts whether I have done it right) I checked overdispersion (variance > mean), theta parameter > 1, there is no zero-inflation). Are there any other requirements that I should check before deciding to switch from Poisson to negative binomial regression?
Comment: The marginal distribution of the response in a Poisson regression is not Poisson, so checking for over-dispersion of the raw response does not appear to address the issue of whether the conditional variance is similar to the conditional mean, or larger/smaller than it. Typically even if the response were (conditionally) *under*-dispersed, the marginal distribution would still be over-dispersed.
Answer: Switching from Poisson to negative binomial regression is a common step when dealing with count data that exhibit overdispersion, meaning the variance exceeds the mean, which violates the Poisson assumption that the mean and variance are equal. You've correctly identified overdispersion and checked the theta parameter (indicating dispersion in the negative binomial model) and zero-inflation as key factors. Here are additional considerations to ensure you're making an informed choice in selecting negative binomial regression over Poisson:
Beyond checking for overdispersion, it's crucial to inspect the residuals of your Poisson model. If the residuals show patterns or are not randomly distributed around zero, this could indicate that the Poisson model is not fitting the data well, supporting a switch to a model that can handle overdispersion, like the negative binomial.
You've mentioned there's no zero-inflation, which is good. However, it's important to ensure this determination is based on a robust analysis. Zero-inflation occurs when there's an excess of zeros in the data than what the Poisson or negative binomial distribution would predict. Since you've ruled this out, it strengthens the case for using the negative binomial model if overdispersion is present.
Use statistical tests or criteria like AIC (Akaike Information Criterion) or BIC (Bayesian Information Criterion) to compare the fit of the Poisson and negative binomial models to your data. Lower values of AIC or BIC suggest a better fit. This quantitative comparison can provide a more objective basis for choosing between models.
Ensure that the relationship between your covariates and the response variable fits the assumptions of the negative binomial model. For instance, the link function used (usually log) should appropriately model the relationship between the covariates and the expected count.
The negative binomial distribution is more flexible than the Poisson, allowing for a varying mean and variance. If the theoretical distribution of your data suggests variability beyond what a Poisson process would generate, this theoretical justification supports using a negative binomial model.
Robustness Checks: Conduct sensitivity analyses to check the robustness of your model's conclusions. This can involve varying model specifications or subsets of data to ensure that your findings are not overly sensitive to specific choices made during modeling.
By systematically going through these steps, you'll be better positioned to decide whether the negative binomial regression model is the most appropriate for your data, ensuring that your analysis is both robust and well-justified.


How to create a repeating gif style imagery for a game tutorial dialog

Question: I want to create a gif style video that shows up in a tutorial window using Unity. How can I make this? Do I record the thing I want to show and then put it in a texture?
Example:
Comment: "Do I record the thing I want to show and then put it in a texture?" That's certainly one way to do it. In games this is usually called an animated texture or flipbook texture. Unity's particle system has built-in support for playing this kind of animation, but it's not too difficult to add the functionality in other ways.
Answer: Whole sprite animation with PNG sequence in mecanim is one way to go and loop the animation with delay for repetitive showcase. [Will take more asset space]
Or you can animate all small pieces in mecanim and loop it with delay for repetitive showcase. [Will need less asset space]
Answer: Since it appears that what you are doing is tutoring people in game mechanics, an elegant solution presents itself:
Use the game mechanic you're tutoring.
If the architecture of your game allows it, create a scaled game board that is set up in a useful tutorial state, allowing a player to either trigger the mechanic as they would in game (with some kind of indicator, like a glowing square in this case, if necessary), and with a button named 'Show me!' that has a computer player do the action, triggering the game mechanic.
If the architecture of your game doesn't support making a scaled board like this, consider replacing the popups with tutorial levels instead, where the RNG is cooked to give the desired assets to the players to complete the tutorial (as applicable).
Edit:
As an alternative, nix the tutorial all together and throw the player into the deep end, keeping track of what game mechanics they've triggered and seen.
Whenever a new game mechanic is discovered, instead of a pop up, slide in a bumper with a brief explanation of what just happened; if possible while the action is still going on, pausing the view and letting the player absorb the information at their own pace until dismissal of the bumper.


Does the activation of a burglar alarm give police cause to enter a house without a warrant?

Question: If police are advised that a burglar alarm has been "set off," does that in itself mean police can intrude into the home to determine the cause of the alarm, absent evidence to the contrary?
Answer: Yes
If a police person has probable cause to believe a crime is in the process of happening then he or she can enter premises without a warrant.
Under the exigent circumstances doctrine some people must be under danger, evidence must be in danger of being destroyed or a suspect must be fleeing.
If these circumstances have been proven then plain view doctrine applies to any evidence or contraband seen in the process on which these circumstances hinged.
It is probably safe to assume that a police officer responding to an alarm is justified in believing some people may be at risk of harm.
Probable cause is considered at the time of entry. There are a myriad of things that can lead to a false alarm but the police person cannot know this unless he or she investigates.
Comment: It is a nice answer +1. But I think that the OP was interested in learning if the activated alarm was in itself enough to justify the probable cause. You address that in your last paragraph but that point is far from conclusive ("probably safe to assume") and I can think of several fringe cases when it would not be enough. For example, the police officer itself activating the alarm, or the police officer that the alarm was activated by someone who threw and stone and then fled.
Comment: The answer is incorrect, as exigency is an exception to the probable-cause requirement, not an example of probable cause. And even then, a tripped burglar alarm is not necessarily sufficient to establish exigency.


Deactivated Facebook, can't continue games on Messenger

Question: I deactivated my Facebook account. Every time I go to Messenger to continue playing a game,  it wants me to log back into Facebook. Then I receive emails thanking me for coming back to Facebook. How can I keep Facebook deactivated and still continue games on Messenger?
Answer: No, that is not possible as of now. Because games are associated with your Facebook account. You can use Messenger without having an active Facebook account just to have conversation with your contacts but you cannot use any other service of Facebook by just login to Messenger.
You will not be able to access Gameroom if you deactivate your account.


Why do my chili leaves turn white?

Question:
Why are chili leaves turning white? Did I spill the plants or do they lack enough nutrients?
Comment: Looks like sunburn to me. Did you harden off properly?
Comment: Have you tried anything yet?
Comment: Did you put them outside from inside? If so, that's sunburn. Be careful, too much direct sunlight without any hardening can destroy all leaves. And your plant will eventually die, I don't think pepper is able to produce new leaves so quickly (unlike swet potato for example)
Comment: Not yet, only reduced watering, don't know what to do, these are my first chilis.
Comment: Is that multiple plants in that pot, or are those branches?
Answer: That would be sunscald caused by the changes from putting a plant outside (from inside, or wherever). I've had that happen before, and that was the reason.
To avoid this in the future, you can try hardening the plants off. Sometimes it happens anyway, though. It's not a disease nor a deficiency; it's not caused by over-watering. It's just dried out leaf. I wouldn't expect a terrible lot more damage, but extra potassium and less sunlight should reduce the problem, if it spreads.
Another way to avoid this is by winter sowing. Another is to keep your plants outside during the day from the moment they sprout (ideally a few days before they sprout). The problem with this is you need to be consistent, and the plants might not get terribly large before the transplant, due to cool outdoor temperatures (but they can be hardened off perfectly).
Deficiencies generally result in yellowing of some kind, purple on the leaves, or such. If it were from disease, the dried part would most likely be a lot darker (if there were a dried part at all). I've never seen chlorosis make a plant white like in that Wikipedia link, though; that's curious (and not the norm for tomatoes and peppers). Zinc and magnesium deficiencies can make plants look kind of white-ish in parts, but it looks different.
Answer: I think it could be early signs of chlorosis:
https://en.wikipedia.org/wiki/Chlorosis
It can be caused by a bunch of things. If I were you I would just top it off with compost and make sure its getting just the right amount of water and light.
You could also try pruning off some of the lower leaves, and holding off on watering until the leaves wilt just a little, put some pressure on the roots to expand a little.

Why do my chili leaves turn white?


Can I enable antialiasing in the solid view during orbit / pan?

Question: I seem to recall a setting that would enable anti-aliasing during viewport transforms in solid mode, but I can't for the life of me remember where this setting is or if it even exists. I think it was called something like "Fast Preview" or something similar.
I've installed a few different Blender builds and I'm concerned my preferences may have gotten corrupted and/or this setting was disabled inadvertently.
Here's a pic (this is during orbit):

Notice the jaggies on the bottom of the left chair.
Anyone know how to do this?
Answer: You can control the Viewport Antialiasing from Preferences > Viewport > Quality:


norm of (sub)stochastic matrix

Question: Is there any bounds for the norm of sub-stochastic matrix? (But it's not doubly stochastic matrix, I mean only the row sum is less than 1, while the column sum may not.
Comment: Which norm are you interested in? If talking about the norm induced by the infinity norm over the state space  ($\|x\| = \max\limits_{i}|x_i|$) then in general you can only say that for the sub-stochastic matrix $A$ you have $\|A\| := \sup\limits_{\|x\| =1}\|Ax\| \leq 1$. Further bounds depend on the structure of $A$.
Comment: I mean spectral norm.
Answer: A useful and easy to compute bound is given by the reasonably well-known relation (see e.g., this Wikipedia section)
\begin{equation*}
\|A\| \le \sqrt{\|A\|_\infty \|A\|_1}
\end{equation*}
between the spectral norm, and the induced $1$ and $\infty$ norms of an arbitrary matrix $A$.
Corollary: If $A$ is elementwise nonnegative and row-stochastic, then
$\|A\| \le \sqrt{\|A\|_1}$.
Note
For some refinements of the first inequality mentioned above, please refer to this paper by V. Nikiforov.

norm of (sub)stochastic matrix


Android emulator: could not get wglGetExtensionsStringARB error

Question: I am getting this error in the android emulator logs since I updated the SDKManager and ADT:
[2012-07-10 15:51:23 - Emulator] could not get wglGetExtensionsStringARB
What does it mean? And is there anything I can do about it?
Comment: Also getting this error.
Comment: Please refer to this [answer](http://stackoverflow.com/a/8948724/1320263)
Comment: Thankyou. Please add your answer if you would like me to vote for it.
Comment: I'm facing same problem, but here i'm using the windroy app,
Answer: I faced the similar problem. In my case I had created the new virtual device and had enabled the snapshot. I just unchecked the checkbox Go to AVD Manager -> Select the device -> click Edit and uncheck the Enabled checkbox.
I hope this works.
Comment: On version R22.0.1 for Windows, I cannot find any checkbox named "Enabled" on the device edit dialog.
Comment: I dont have that checkbox is checked. Visual studio works like a charm!
Answer: When you create the emulator, you need to choose properties CPU/ABI is Intel Atom (installed it in SDK manager )
Answer: just change your JDK
I installed the JDK of SUN not Oracle and it works for me....
Answer: For me changing the Emulated Performance setting to "Store a snapshot for faster startup" and unchecking "Use Host GPU" fixed the problem.
Answer: First of all, use INTEL x86... this as CPU/ABI.
Secondly, uncheck Snapshot if it is checked.
Keep the Target upto Android 4.2.2
Answer: I ran into this issue running Android Studio 1.4.
In the Android Virtual Device (AVD) Manager, I had checked the 'Use Host GPU' box, thinking this would give me some sort of boost in the emulator's speed.
Android Studio will let you choose a device that's configured that way, and it will show you the command it used to start the virtual device:

but for some reason, it doesn't warn you that the program crashed, and it doesn't show you the stderr message that you would see had you run it from the command line yourself:

When I ran it from Android Studio, I didn't see the dialog box in the screenshot above, though it shows up just fine when you run the command from the command line,
so I just sat there patiently for a few minutes while nothing happened.

As pointed out elsewhere, the drivers needed for the Use Host GPU option are not yet available. Reading through that post, it appears that this setting can be used with some Intel CPUs but not the ARM chip I chose (see CPU/ABI setting below).
My solution was to just uncheck the "Use Host GPU" box which is near the bottom of the window opened through the 'edit' option after choosing the virtual device in the Android Virtual Devices tab in the AVD Manager.
You can get to the AVD manager directly in Windows at
%ANDROID_HOME%\AVD Manager.exe
where in my Windows 8 install, %ANDROID_HOME% resolved to
c:\users\myusername\AppData\Local\Android\Sdk
I don't have it running on Linux at the moment, but I'd assume it's in a similar path there, i.e.:
${ANDROID_HOME}/

After unchecking the 'Use Host GPU' box, I opted to check the 'Snapshot' box next to it (as I understand, that stores a copy of the already-built vm so it doesn't need to get rebuilt every time, which should save some startup time for future instances). Here are the full settings I used:
Answer: i had a same issue because of my Nvidea Graphics card Driver Problem.
If your System has Dedicated Graphics card then Check for the latest Driver and Install it.
Other wise simply Choose Emulated Performance as Software  in Emulator Configurations

After Updating the driver the issue is resolved :)


Create Contacts From Inbound Email Body?

Question: Is there a way to have CiviCRM create contacts from email addresses found in the body of an inbound email?  We have a number of different sources that send us emails with addresses in the email bodies that we want to capture (for example, we receive volunteer applications from a form on our website, and also from VolunteerMatch - both contain the applicant's email address in the email body).  However, it looks like inbound email processing only parses email headers by default.  Is there something obvious we're missing?
Comment: you are not missing anything obvious imo
Answer: This would require an extension to do.
That said, I'm not sure this is the best approach for your use case.
If you have a form on your website, it seems like it would be better to integrate that form directly with CiviCRM instead of using inbound email processing.  For VolunteerMatch, I would use their API with Form Processor to process the message rather than inbound email processing.
That second item is a complex solution if you're new to CiviCRM, but within the reach of a non-coder, as opposed to writing an extension.


Android: simulate scroll event to underlying screen

Question: I am trying to make an application that does a sort of auto scroll. The idea I have is to have a floating button (like the facebook chat head) with two buttons, one for scrolling down and one for scrolling up.
The problem I am facing is, I have no idea how to pass a touch/scroll event to the underlying screen. I had found this github gist: https://gist.github.com/oneyoung/a14c99856c3984263734 , it uses a Context to pass the movement to, but since I want it to pass it to the underlying screen my guess is the Context will change and this will no longer work.
Any thoughts on this or directions for me to look in are welcome, thanks in advance!
PS. Here is a screenshot to get an idea of what I currently have: https://i.stack.imgur.com/B2w3z.jpg
Comment: Can you provide the layout, to better understand the structure.
Comment: You mean the layout as in the xml file?
Answer: OK so, with the provided github gist, it is possible to send user input programmatically to your device. As for the Context, a Service is a Context in and of itself so you can just pass that as a parameter for the Input constructor in the onCreate method, like so:
public void onCreate() {
  super.onCreate();
  Input input = new Input(this);

But the problem lies with passing the input to the underlying screen. This is only possible with system permissions, meaning you would need root for this as it throws an error saying: W/System.err: Caused by: java.lang.SecurityException: Injecting to another application requires INJECT_EVENTS permission
Answer: send touch events to a device via adb
You can send touch events via shell to android. I think this is something similar to what you want.
Comment: Yes, the phone needs to be plugged into a computer for this, not? And I want it to be standalone, no plugging of sorts.
Comment: I dont think you need it to be plugged in. you can just use the input utility to send events from your android app


Can an Android app steal cached/stored passwords from other apps on my phone

Question: Can an android app steal a stored password from any other app I have installed?
Say I have snapchat and I only log in once and stay logged in, if I later delete the cache from that app it will log me out.
Are the stored passwords vulnerable?
Comment: Are you allowing the possibility that the android device could be rooted? If so, anything on the device should be considered vulnerable. See my answer below.
Answer: Welcome Alfredo :)
TL;DR
No. Android apps are "sand-boxed" inside their own user in the operation system. So unless Snapchat/you Android version have a specific vulnerability (and if you update your phone this shouldn't happen), other apps are not able to get stored passwords.
Application Sandbox in Android
Android is based on the Linux operation system. Thus, it isolates apps from each other and protects apps and the system from malicious apps.
To do this, Android assigns a unique user ID to each Android application, which means all the application files, unless defined otherwise, are protected and accessible only to this specific application (user id).
Other mechanisms for saving users passwords
Android also implemented an account manager, in order for apps to save tokens and passwords securely. In short - that's an encrypted DB that is managed by the operation system itself, and every app could save tokens/passwords using it, in a secure manner.
Comment: The only exception would be if the app saved the data on the SDcard for some reason.
Answer: It depends on what you mean by storing the password. It may be done by each app persisting the data in SharedPreferences, or in something like a sqlite database, or file-based storage. Or, perhaps you're referring to the the android keystore provided by the system.
In the first case (SharedPreferences, sqlite, etc.): By design, each app is supposed to be in its own sandbox. Other apps should not have access to their data. The protection is based on linux permissions. However, there are vulnerabilities, so SELinux has been used in recent years, and the permissions are getting stricter and stricter with each version of android, e.g., what system data that ordinary apps can access is more and more restricted.
In the second case, it could be considered more secure, managed by the android system.
However, it is very common to find android devices that are rooted. The process of rooting removes many of the protections, so android keystore and other app data should all not be considered as safely stored. Some apps like bank apps, or games like Pokemon Go, implement root detection features to prevent the app from running on rooted devices.


What rockets are currently capable of carrying humans to Mars?

Question: No particular emphasis is placed on a particular rocket but rather if a rocket capable of carrying a human payload exists.
Answer: The answer is either "none" or "all", depending on how you look at it.
The limiting factor is how you intend to launch the spacecraft that's actually going to carry the people to Mars.
For reference, the Apollo CSM massed about 12000 kg dry (no propellants or consumables).  The CSM could keep 3 people alive for a period of a week or so; figure a spacecraft to Mars would be considerably bigger.
If you want to send the whole shebang off in a single launch (as with the Apollo missions), then you're going to need at least an SLS Block II class rocket (50,000 kg to TMI), and even then I'm not sure that's adequate (Orion is not going to be the transfer vehicle - it doesn't have the lifetime for a trip to Mars).  The ITS as originally envisioned by SpaceX is insanely, stupidly huge, making the SLS look like a bottle rocket, and even then the concept requires 2 launches (one to launch the transfer vehicle, one to launch the fuel for the transfer vehicle).
Note that SpaceX is scaling back on the ITS a bit, from 12 m diameter to 9 m, which is still huge.
No commercial launcher currently in production will be able to do it.
However, if you send your transfer vehicle up as a series of smaller modules that get stacked and fueled in Earth orbit (sort of like the ISS), then pretty much any launcher is up to the task, you just have to size the individual modules appropriately.  A FH (or similar class launcher) could lift the transfer spacecraft modules (along with propellant and consumables), and an F9 (or Atlas) could launch a Dragon (or a Starliner) as a taxi.
This would not be easy, but it would be more tractable than trying to do it all in a single launch.
Edit
If all you're concerned about is sending the equivalent mass of a person (or several people, say several hundred kg in total), then almost any launcher in use today can get that mass to Mars - a good chunk of the Mars exploration program was launched on an Atlas V.  If your human payload doesn't have to survive the trip, you're golden.
Again, the issue isn't the people themselves, but the spacecraft required to keep them alive and healthy for months at a time in space.  That's going to be your limiting factor for any human spaceflight.
Comment: The original ITS would require up to 6 launches, actually; 1 for the transfer vehicle, then up to 5 tanker launches. (I believe the variance depends on what trajectory is used)
Comment: @DylanSp: Thanks - I knew it would require more than one launch, but for some reason I thought it only required one additional launch for fueling.
Comment: @JohnBode The idea is that Orion plus an attached module (like the Deep Space Habitat) would be used for Mars, but yes that plan would involve considerably more dry mass.
Answer: Any rocket that can carry humans (NASA would say Falcon 9, Atlas V in the near future, China would say Long March 2F, ESA would say Ariane, Russia would say Soyuz) can carry them to Mars.
In reality most plans for Mars missions involve launching the transit vehicle on one booster and then the crew on another. SpaceX with ITS/BFR is actually the opposite and suggesting doing everything in one launch (well maybe multiple refueling launches of other vehicles, and then crew on a single vehicle).
So it is almost immaterial which rocket could take them to Mars, since it is really the first step of getting into orbit that matters.
Or you could have meant, does any rocket active today have the ability to launch from the surface of the earth direct to Mars.
Maybe SLS will one day, maybe Falcon Heavy, maybe ITS/BFR but nothing really available today.
Comment: Any rocket that can carry humans can carry them to Mars? Only without landing on Mars nor a return to Earth.
Comment: More like, no one seems to plan a direct launch from earth to Mars at the moment except SpaceX.  So any rocket that can get you into orbit and dock with a Mars craft will do.


Could anyone give me a visual representation of what a limit point looks like?

Question: I'm currently in a real analysis class right now, and we are learning about open and closed sets. We are discussing the concept of limit points, and I am having trouble visualizing them. I usually picture a circle with a closed, solid outline and that the limit points are contained on that outline. If a set is closed, it contains all of its limit points. I know open sets can have limit points as well, but I always imagine open sets as a circle with a dashed outline. Could someone perhaps draw me a visual representation of a limit point in relation to its $$ \epsilon- neighborhood? $$ Thank you!
Comment: Okay, if you image the universe being R^2 (which is not always a good idea).  There are three types of limit points.  There are points that are "completely" in the set so that there is always a circle around it that's complete in the set.  There are limit points on "the edge of set" so that every circle around the set has to intersect and have many points in the set.  And limit points "just by the rim" these points aren't in the set but are so close that every circle intersects the set.  You *MUST* remember closed and open are *NOT* opposites and "interior" and "limits" aren't either.
Comment: You can have a "foggy" misty set like Q in R.  Every real number, rational or not, is "right up next to" a point of Q so every point is a limit point.  THis misty set is not closed because the irrational limit points are not in it.  This misty set is not open either because none of it's points are "entirely" inside it so that there is a circle completely in the set.  (So there are no interior points)
Comment: You can have a solid set like a disk.  Every point "inside" the disk is both a limit point and an interior point as there are always circles around the point that are enitrely inside the set.  The edge points are not interior points but are limit points as every circle intersects both points in the set and not in the set.  So the disk is open if none the edge pieces are in the set (so only the interior points are in the set).  The disk is closed if all the edge peices are in the set (so all the limit points are in the set).
Answer: This:
$$(  \bullet  ) \hspace{-16px}\color{red}{\left(\begin{matrix}\quad\quad \\ \quad\end{matrix}\right)}   \quad\quad\text{ bigger $\epsilon$ }$$
where $\color{red}{\left(\begin{matrix}\quad\quad \\ \quad\quad\end{matrix}\right)}$ is the set you want a limit point of and $(  \bullet   )$ is an epsilon neighborhood around the point $\bullet$.
Making the $\epsilon$-neighborhod smaller, the interval enclosed in the black parentheses will still intersect the interval with the big red parentheses.
$$( \hspace{-4px} \bullet \hspace{-4px} ) \hspace{-11px}\color{red}{\left(\begin{matrix}\quad\quad \\ \quad\quad\end{matrix}\right)}   \quad\quad\text{ smaller $\epsilon$ }$$
Hopefully the diagrams render the same for all viewers.
Comment: But I think it's important to realize *this* is also a limit point: $\hspace{-16px}\color{red}{\left(\begin{matrix}\quad\quad \color{black}{(  \bullet  )}  \\ \quad\end{matrix}\right)}   \quad\quad\text{  }$ (it's bot an interior point AND a limit point.)
Comment: Yes! I knew it but neg-, lected to include it so, I'm glad you drew it.
Comment: I think my confusion when I was a student was thinking limit points (which if all are in S means S is closed) and interior points (which if all points of S are) were different or opposite ideas somehow when in actuality they are not at all.
Comment: The interior and the boundary are both always subsets of the set of limit points, yes? Regardless of choice of metric, topology, etc.
Answer: Imagine any neighborhood of a point $x$. If every neighborhood intersect a set $A$ in a different point than $x$ then $x$ is a limit point of $A$.
To simplify: in the standard topology of $\Bbb R$ an $\epsilon$-neighborhood is any open interval of the kind $(x-\epsilon,x+\epsilon)$ for any $\epsilon>0$ (the $\epsilon$-neighborhood is a basis for all neighborhood on the standard topology in $\Bbb R$, so any result that holds for $\epsilon$-neighborhoods holds too for any other kind of neighborhood).
Then if $\forall\epsilon>0, (x-\epsilon,x+\epsilon)\cap A\neq \{x\}\text{ or }\emptyset$ then $x$ is a limit point of $A$. The thing to visualize is the concept of $\epsilon$-neighborhood intersecting $A$ in a different point than $x$, this is the image for this context.
Answer: You can imagine that if $x$ is a limit point, then don't matter how close you look, you ever found another point of the set with him.
Or you just can imagine that it is not a isolated point, that is more easy.


Why don't our Gods and Goddesses prevent Kali Yuga from happening?

Question: Nothing to add here, but it is mandatory, so...
Comment: because everything should have start and end points, if nothing happening no use of it.
Answer:
Why don't our Gods and Goddesses prevent Kali Yuga from happening?

Because it's part of the plan and leela of Brahman, and the adharma in kali yuga is actually sanctioned and brought about by Brahman. This is all part of Brahman's leela (divine play). The yugas of satya, treta, dwapara, and kali all arrive and disappear at specific times managed and coordinated by Brahman.

Kaushitaki Upanishad - For he, Brahman, makes him, a soul, whom he wishes to lead up from these worlds, do a good deed; and the same makes him, whom he wishes to lead down from these worlds, do a bad deed.

Your question can really be reduced to, "Why does God allow bad things to happen?". And one answer is given in the Bhagavata Purana:

7.1.8 - When the sattvaguna is prominent, the rishis and devatas flourish with the help of that quality, with which they are infused and surcharged by Brahman. Similarly, when rajoguna is prominent the asuras flourish, and when tamoguna is prominent the Yakṣas and Rākṣasas flourish. Brahman is present in everyone's heart, fostering the reactions of sattva-guṇa, rajo-guṇa and tamo-guṇa.

So good and bad actions are actually caused by the Lord, in accordance with the free will of Jivas. In Kali yuga, the Lord Brahman causes the adharma of humans according to their free will.


Is it best practice to have a file only of "includes/requires"?

Question: I have 5-10 files on one server that all catch XMLRPC-PHP requests.  There's about 20 lines of require_once in each one that are all the same.  It'd make life simpler for me to create a separate file that only has the requires and require that in my XMLRPC files.  Is this best practice, or does it open up issues that I don't know about?
Comment: Have you considered consolidating the includes into a single file, perhaps as part of your build step? The performance gain can be worth it.
Answer: I've done that before and it did save some effort, but got it fiddly as I didn't always need every single file and sometimes needed a few more. If you always need those and only those, then I think it's a good plan.
However, there are alternatives if you have control of the file hierarchy and are not using third party libraries e.g. using php's __autoload() function to have the files automatically included when you try to instantiate the class. I'd tend to prefer this if at all possible as it needs a lot less maintenance.
Answer: Basically any set of identical code in multiple places should be consolidated.  As long as you're sure the exact same set of includes are required in each place I would put them together in one file.  The performance difference (if any) is negligible and maintainability is more important.
Answer: Yes it would definitely make your life simpler. As mentioned by others before, I would recommend using the autoloading mechanism.
There is an implementation in the PHP manual, I found it pretty useful. It might look something like this:
function my_autoloader($class) {
    include 'classes/' . $class . '.class.php';
}

spl_autoload_register('my_autoloader');

// Or, using an anonymous function as of PHP 5.3.0
spl_autoload_register(function ($class) {
    include 'classes/' . $class . '.class.php';
});

If you are on PHP 5.3, also consider using namespaces. It's actually even easier to have a good structure and a simple autoloader implemented by default:
spl_autoload_extensions(".php"); // comma-separated list
spl_autoload_register();

However, I remember a bug there. Usually I have a 'bootstrap' file, with this autoloader:
spl_autoload_register(function($class) {
    if(file_exists('./lib/' . str_replace('\\', '/', $class) . '.php')) {
        require_once './lib/' . str_replace('\\', '/', $class) . '.php';
    }
});

Using this mechanism, you have a folder structure that mimics your namespace structure. With this approach, you have a good structure, and do not need to care about including your libraries and other classes.


Monitors wont go to sleep and screen won't lock in 16.04

Question: My ubuntu 16.04 with gnome desktop won't go to sleep or lock the screen. In the power options menu I have set 'blank screen' to 5 minutes, and 'dim screen when inactive' to on. Also, I noticed that scrolling the screen brightness slider isn't working. So I can imagine that the screen brightness is set to 0 when inactive, but the mechanism behind that simply doesn't work, although my screen also doesn't lock. I've found some information about this by googling, but it's all about older ubuntu versions so I don't think it applies to me.
Answer: I solved my problem by running unity-tweak-tool and removed check disabling "Desktop Lock". Choose System, then Desktop icons, then click Security tab. Make sure that there is no check against Desktop lock.
Comment: I'm using gnome so I don't really see the point in using a tweak tool for unity. I installed the tweak tool anyway in the hope that it might fix this issue,  but found that the checkbox was unmarked by default. So this is not the problem.


Do you take his word against/over mine?

Question: What preposition seems to fit in this sentence? What will the difference in the meaning of the sentence?
Comment: `against` implies a competition. As in: "It's your word against mine." It's not clear whose word will win at this time. So they're at equal footing. Hence, `against`.

"Do you take his word over mine?" In this case, the 'taker' has already decided whose word will win. Therefore, `against` doesn't make sense here. `Over` is the right choice.
Answer: I've personally heard "your word against mine" far more frequently than I've heard "your word over mine" - I find I have an unexpected bias in that the "over" construction seems to me to indicate lesser educational attainment in the speaker.
Google ngram shows a huge distribution differential which supports my internal expectations to a large degree:

Google NGRAM chart for these terms- English corpus, 1800-2018
Of course, knowing the most commonly-used between the two variants doesn't answer the portion of your question pertaining to implications - for that I would say I agree with @Tushar Raj's take on the implication of the phrasing, with a caveat - the active person doing the assuming is not in fact the "taker" - the use of "over" in this phrase implies that the asker is assuming that the person to whom they've addressed the question has at some level already decided that "his" word has been deemed more credible than "mine"...
Hope this helps.

Do you take his word against/over mine?


Forum or Forums?

Question: When do I use "forum" versus "forums"? Some websites are using "forum", but some others use "forums".

https://forum.joomla.org
https://forums.linuxmint.com
Answer: Either can be used.
A forum deals with one topic whereas the word forums is used to group each forum together.
Incidentally there are people (sometimes highly educated but more often just pains in the necks) who prefer the "original" plural form in Latin: fora
Answer: You can use either word. In the first case, forum is probably used because the topic is always Joomla, although there are sub-forums, one for each orange header. In the second case, they preferred seeing the sub-forums as separated forums, and use the plural.
On Drupal.org, the URL for the forums is https://drupal.org/forum, although they are referred as forums, when somebody posts an issue about their own sites in the Drupal.org webmasters queue and they are suggested to ask in the forums.

Forum or Forums?


No .altcoin directory being generated

Question: I am trying to create a genesis block for a personal play coin. I get the correct output of assertion failed. However when compiling I noticed the ./altcoin folder is not created at all.
Answer: The data directory (~/.altcoin) is created when the software is run, not when it is being compiled. Compilation has nothing to do with the datadir.
Comment: Thank you for your comment Andrew I actually was able to get the debug.log to work and create the merkle and hash with a little workaround.

Getting a fatal error
`ERROR: ReadBlockFromDisk: Errors in block header at CBlockDiskPos(nFile=0, nPos=8)`
Wondering if you happen to have a suggestion for this?
I tried reindexing that didn't seem to make a difference, is this related to genesis not being mind?
Comment: It means your genesis block is invalid. You probably did not mine it so it does not have a valid proof of work. You actually have to mine the genesis block and make sure it has a valid PoW.
Comment: I guess my confusion lies with the fact that if with that error I can't connect the seed nodes to actually mine the block or am I looking at this wrong?
Comment: Normal miners won't be able to mine the genesis block. You have to temporarily modify your altcoin client to mine it.
Comment: Thank you that gives me an idea where to start looking, i appreciate it!

No .altcoin directory being generated


Bcoiner wallet - balance is showing as zero?

Question: please help! I sent to my wallet 450 dolars of bitcoin, and transactions are confirmed strongly 62 times, but my wallet says that I have 0 bitcoins to spent and I cant sell it!!! What to do? Whats happening? thank you so much for answers!
Comment: What wallet is this? Can you post a transaction ID or receiving address?
Comment: I add one more screenshot in post above. its a bcoiner app. First time here, thanks for understanding.
Comment: I meant bcoiner wallet. Its a scam isnt it? 450 dollars!!!!!
Comment: The transactions paying to you were confirmed, but there have been a few subsequent transactions moving those coins to new addresses: txID 4d88a869b354b64a14d384939d1d801966733b892c07c189e9ceace3a57c49bd and then txID cb1fc617b635f851d79123f5e1fe16c98948c421445007ca11a2050ed4213355. The coins now reside at address 14qCMrBxt21idaa9FzZ5VBUKpy3rztXEvF. --- I am unfamiliar with bcoiner wallet, but a quick search reveals a help page on their site. If you did not make those transactions I would recommend contacting them to see if they can help.
Comment: In general, I would recommend using wallets that are well-known and well-reviewed (and most definitely, open source!). Bitcoin.org has a list of recommended wallets that is a good place to start from.
Comment: I already did. they answered me with some bullshit. I mail them again, no answers. So I guess I lost that , ha?
Comment: Happy to help. I do hope that you have not been scammed, and considering a lot of the world is celebrating holidays right now, maybe the support staff is just on vacation (wishful thinking, maybe). But otherwise, it is definitely best to stick to known wallets, and make sure you download them from trusted sources (or build from source code yourself).
Comment: thank you for the optimism. I hope so too. It's still writing in my wallet that I received 450 dollars and I didn't send it anywhere, so let's hope! Thank you! I will be much smarter next time!
Comment: @user101526 https://www.blockchain.com/btc/address/14qCMrBxt21idaa9FzZ5VBUKpy3rztXEvF - No the coins are spent shown here few hours ago did you cash it out
Comment: @user101526 I'd recommend www.blockchain.com they have a wallet that is fantastic btw I also hav ledger, a hardware wallet. They never had any problems I used it so far
Comment: @user101526 - I think it maybe just a bug in bcoiner wallet since they've shown the value?
Comment: @Duckduckgaga I would recommend avoiding the blockchain.com wallet. See https://bitcoin.org/en/choose-your-wallet for some well-respected choices.
Answer:
Whats happening here

As others have commented, the money was received by the address in your wallet but was subsequently spent.
Since your wallet doesn't show the expected balance but also does not show the spends it seems there is some flaw in the app or in the service behind it. Whether this is a malicious flaw is impossible to say.
Since you didn't spend that money, someone else must have. That suggests the wallet has been compromised or the underlying account in the bcoiner service has been compromised.
Since bcoiner support have been unable to resolve this to your satisfaction, it might be prudent to avoid putting any more money into this wallet.

The bcoiner wallet is not an app I personally would use for the following reasons:

Unresolved woe - There are several stories similar to your own on this website. All wallets have some such stories associated with them but most also have some history of such problems being resolved or being found to have a more reasonable explanation than possible theft by app developers.

Suspicious review profile = Profile of reviews on Google Play seems suspicious to me. There are many 5-star reviews obscuring 1-star reviews (mostly similar experience to yours) and not much in between. Either this is a great wallet with some flaws or somebody is submitting fake 5-star reviews in a way that Google Play doesn't detect. The developers responses to the 1-star reviews are rather uniform and unhelpful. The evidence here is very weak, but I'm inclined to be cautious when choosing software that has control over money.

Custodial? - I have seen allegations that this is a custodial wallet. I would not want to use a custodial wallet.

Not open-source - It is proprietary closed-source not open-source, I prefer open-source wallets.

In the end I suggest you make a decision based on the quality of support you receive from bcoiner developers and from the community of bcoiner users.

It may be worth searching this site for other questions about bcoiner and using that information to help you to decide what action to take and whether to select a more popular and better supported wallet app.

Appendix - Google Play reviews:

Bcoiner - too good to be true? surprisingly polarised?

Mycelium

Blockchain (their non-custodial app, not their custodial wallet service)

Bitcoin Wallet (Schildbach)

Electrum - A formerly well-regarded wallet afflicted by a security flaw and a badly received recent update?

I found it revealing to actually read the reviews sorted by newest first and get a feel for the range of feelings expressed and the variety of subject matter and writing styles. Doing this for several wallets gives you an impression of what is normal and what is not.


Could a significantly powerful caster use create demiplane, permanency and astral projection to gain nigh-immortality?

Question: A scenario for a villain I came up with at one point was an insanely powerful mage who keeps her real body in a demiplane with the timeless trait. In order to beat the heroes she only sends astral projections of herself and since she's so strong no amount of killing astral projections will stop her. The only way to beat her would be to find the coordinates to her demiplane and kill her there on her own terms. Ignoring whether or not this would be fun, since making an op nigh immortal caster as the BBEG would be difficult to pull off without becoming extremely obnoxious, would it even be remotely possible in Pathfinder lore? I mean could an NPC be even powerful enough to negate the repercussions of having an astral projection destroyed multiple times? Assuming they are not a god or similar being. I can figure out the exact details after I've confirmed it's even possible.
Comment: Not an answer, although _maybe_ a frame challenge, sorta:  Could your villain use a Clone or similar spell to send physical copies to fight the PCs while keeping their original body safe?  Or, if they don't mind the body swapping, use their original and escape to the Clone if they die?  That's the most common immortality exploit you hear.
Answer: If nothing else, there's always cutting the silver cord:

While you are on the Astral Plane, your astral body is connected at all times to your physical body by an incorporeal silver cord. If the cord is broken, you are killed, astrally and physically.

There is no protection from this; if the cord is severed, the caster of astral projection dies, period. The silver cord itself is somewhat protected by virtue of being incorporeal, but presumably anything that can damage incorporeal objects, like a ghost-touch weapon, can cut the cord.
In D&D 3.5e, the silver cord was more detailed, and the rules were explicit that it could only be damaged by psychic wind, a githyanki's silver sword, or an astral dreadnought. None of those things is in Pathfinder—and neither is the rule that these are the only things that can damage the silver cord. Literally the only available rule is

Luckily, very few things can destroy a silver cord.

To my mind, ghost-touch and other things that can damage incorporeal objects are probably reasonably considered "very few" relative to all the other ways of damaging non-incorporeal objects. If, however, as GM, you think that ghost-touch is too easy, then by the rules you still are obligated to come up with something—even if the rules don't explicitly say what can cut the cord, they do explicitly confirm that at least a "very few things" can.
Finally, note that, rules-as-written, it seems that the caster's body is always going to be on the Material Plane, so being in the demiplane, technically, wouldn't actually help.

You project your astral self onto the Astral Plane, leaving your physical body behind on the Material Plane

This is almost-certainly an oversight, however, and probably shouldn't be ruled that way no matter what the text says.
Comment: @L.P. Who knows? The spell isn't very clear about it. I would say that a demiplane embedded in the Astral *is not* the same as the Astral itself, so someone in an Astral demiplane wouldn't count as being on the Astral Plane, but nonetheless it's quite possible to read "*leaving* your physical body behind on the Material Plane" as an implicit requirement that you cast the spell from the Material Plane. Which is nonsense but it is what it is.
Comment: I miss-read the text thinking the silver chord no longer mattered once you were materialized physically. Thanks for that.
Comment: In regards to "Leaving your physical body behind on the Material Plane" can one even cast Astral Projection in a Demi-plane? The create Demi-plane spell(s) state that a Demi-plane must be created within the Astral or the Ethereal planes themselves. (If created in the Ethereal then this becomes mote, because it has no connection to the Astral direction, so lets ignore that.) Can one even cast Astral Projection on an Astral-ly bound Demi-plane- would that be more akin to casting AP on the Astral itself? Or does the Demi-plane allow more Material like traits.


How would society be different if people could see the full range of the electromagnetic spectrum?

Question: Say that you have a species whose eyes can see anything from radio waves to gamma waves. Let's assume that it's adapted well enough that it can differentiate between these types of waves, and that seeing that much doesn't completely overwhelm it. Besides for the above modification, it's exactly like us in terms of anatomy and physiology. How would society be different with such a species instead of us, if at all?
Comment: "How would society be different" for about any question is an *extremely* wide scope topic. One could write pages on even a few topics (economics, art, and engineering, for example). Try drastically narrowing this down to one slice of the society pie.
Comment: Worth noting: the EM spectrum is actually unbounded.  Frequencies can go as low as you please.  Whether they can go as high as you please depends on your theory.  They can go at least 1000000000000000 times higher frequency than the cutoff for gamma rays, and if string theory is correct they are actually unbounded, permitting as high of frequencies as you please.
Comment: There's no point in seeing farther down than the near infrared.  The eyes are too small to focus the waves and thermal noise will wipe it out anyway.
Comment: @DonielF What limits are you thinking of?  If you can imagine a wave that's 1m long, you can imagine one that is 10m can you not?  100m? 1000m?  Where would the limit be?  Even if you start looking at waves the size of the universe, you can still have wavelengths larger than that if your boundary conditions are right.  On the small side, there's some who believe that issues arise when the wavelength approaches Plank Length, but there's not universal agreement about whether it's a limit or not.
Comment: @CortAmmon Technically there are limits, no? How can a wave be infinitely long, or infinitesimally short?
Comment: @CortAmmon Of course, I understand all of that. What I mean is that the length of the wave has to be finite.
Answer: Let's ignore for a moment how anatomically impossible this is.
Their life would be full of noise.  From cosmic radiation to infrared emission every object would glow. There would not be a real night, so society would not form around day or night cycles.  They may even be able to see better when the sun is not out spewing noise.
The noise would even be worse as eyelids, even made of lead would not be enough.  There would be no darkness.  In fact you could see things coming from behind you just as well as in front. They would have to evolve to be able to block as much noise out as possible, but it would not be enough as society evolves.
Technology may also get a huge head start as everyone can see radio waves.  We may see primitive radio in the middle ages. Radiation would be discovered by cavemen.  They would find rocks glowing in a color they have never seen before, brighter than anything else in the world and spreading in glow to things they touch.
In the end though technology may be stifled.  Without a discreet way to send signals life becomes very tough.  Who would let a radio station be built, if it was a giant glowing light that you could not stop seeing no matter where you turn?  Eventually all society may prize nothing more than to avoid technology and live in cold caves where they can finally get some darkness.
Comment: Actually let's not ignore whether or not this is impossible. We know plenty of animals that see less colours than we do so why couldn't creature see more of them? [Example](http://sciencing.com/animals-can-see-infrared-light-6910261.html)

Also, just because the communication medium can be detected by both the technology and the user doesn't mean they get messed up. Look at [Li-Fi](https://en.wikipedia.org/wiki/Li-Fi).

Finally, the night we have now isn't as dark as it seems. Think about moon/starlight and our personal [light pollution](https://en.wikipedia.org/wiki/Light_pollution).
Comment: @DerkJanHulsinga Between all colors seen by all animals, it's still just a drop in the ocean that is the full electromagnetic spectrum. You can't clearly detect waves larger than the receptor.  It is also hard to detect rays with too much energy to be absorbed.
Also all our light pollution can be blocked by walls, shades, and our eyelids.  Blocking radio waves is very difficult, and once you do it you lose the ability to use them
Answer: People would stop tanning, cause they know how bad UV rays are for them.
In all seriousness, though, I'd say they'd just appear as far more colors. What makes visible light give color? The fact that we perceive it. If you can perceive the entire spectrum, it's likely they'd all be classified as colors. So you'd have a massive range of colors, some of which would be considered "harmful colors" (uv and shorter). Colors already are used to set a tone, influence a mood, draw attention, give definition, etc. With billions of more shades of colors, they'd be that much more integral to setting tones and moods in society. There would likely be a greater emphasis on color, and visuals would be highly important to everyone (not just guys).
It's a bit tough for me to speculate what colors they would appear to be, but as the visible colors "blend" from red on one side to blue on the other, it's likely radio would be a much more "extreme red", if you will, and gamma rays a more "extreme violet".
Comment: The reason I focused on perception is because it makes it a bit easier to think about. How would society be if everything were grayscale? Colors wouldn't be very important, only shade would be. Appearance and such wouldn't be a big deal. So you have a neon green shirt with neon orange pants. No one notices. But with the addition of color, things have to "match", or go well together. This would be that much more important with far more colors. You could utilize far more colors, but you'd also have to make them work well together. Comparing grayscale to color is like color to the spectrum.
Comment: That might be how they *perceive* it, but how would it change *society*? Would they *react* differently to it than we do to our vision?
Comment: Well, I would assume visuals would simply be emphasized more. Advertisements and such would be far more colorful, so you might have a Star Wars prequals Coruscant type if setting, with lots of color ads everywhere. Though, radio waves would no longer be invisible, so people could "see" a present wifi signal, "see" when the microwave is working, etc. Society would likely have to try to make any technology using light "aesthetically appealing". Radio waves might not look pretty being sent efficiently, so they'd have to change how they send things.
Comment: To achieve ' 1 MeV gamma color' on an advertisment they would still need 1 MeV gamma rays, which are still harmfull.
Answer: People would probably use radio in different ways. When you broadcast a radio program you are using an antenna that emits electromagnetic waves. Such a society wouldn't probably agree to stare at an antenna, the same way you probably don't like to stare at a lighthouse.
X-rays are electromagentic signals too. So, those people would be able to see through some object and through people. So, I think that their medicine would be much more advanced compared to ours, because they would have been able to see through a body since the moment they were able to invent a source of x-rays.
They would have a different kind of art. Think about it. Human artists use all the colors they are able to actually see in pictures. Those people of yours would like to paint in x-rays color, ultraviolet colors, infrared color and so on.
There would probably be many more phrases about colors. Not only "Tonight I'm feeling blue". But instead: "Tonight I'm feeling infrared".
You would be able to know when a person is using his phone, because it would light up, since it sends radio signals. So, at the theaters they would force you to switch off your mobile phone, not just turn down the volume.
The night wouldn't be dark. They would be able to see all the spectrum, so probably we wouldn't have any stories about romantic nights. The only places that are like a "dark room" for your people would be under a mountain.
Comment: The x-ray angle is neat, but I doubt it'd be that significant. X-rays are still quite harmful, so it's better to emit them for just a millisecond and snap a pic than to continually bombard someone with them to look at their insides with eyes. Imo, colors from UV and shorter wouldn't be used too often for being harmful. Seeing them would be like smelling sulfur: you want to get away from it.
Comment: Yes @Iter, I feel I tend to agree.


Can Postmaster update custom fields after sending emails?

Question: Is it possible to make Postmaster update an entry's custom field after it sends an email? I've got a custom field called 'Email Sent' and it'd be nice to stick a 'yes' in there for peace of mind once the email had gone out.
Answer: That's a great idea. Currently there are no hooks or settings in place to do that.
I could also see a setting in place to store the number of times an email has been sent (for re-occurring emails). That way, you could say do not send after X times.
I will add this to the list of features to implement. If you need this immediately, I am available for an hourly rate of course. Email support[at]objectivehtml.com if you need such services.
Comment: Thanks for taking the idea on board Justin. It's only a 'nice to have' for me at the moment so I don't have a pressing need for it. But if that changes before such a feature is ever released, I'll be sure to get in touch via email.
Answer: StackExchange still isn't allowing me to add comments, so I'm doing this as an answer.
A possible workaround is to add a hidden field to the form that sets the value in the custom field. This isn't the same since it will be set before the email goes out, but at least it's something.


Are negative coupon bonds possible?

Question: I am aware that negative yield bonds are possible (e.g. by selling a zero coupon bond at a price greater than par value). Are negative coupon bonds possible? I have not found any real-life examples of bonds that have a negative coupon, so I am wondering why they don't exist.
Comment: What woud be the advantage over "conventional" negative yield bonds? To me this just sounds like a lot more hassle because you have to track the coupons and get the negative interest later (as the bond issuer).
Comment: A savings account with a monthly fee isn't much different than a negative yield bond.
Answer: The simplest explanation is that they don't exist because there's no need/demand for it.
I can't think of any advantages over negative-yield bonds (they don't have to be zero coupon, as long as the price is high enough to exceed the principal + coupons) but there is a significant disadvantage: the issuer would need to track and collect all the coupon payments it's owed, which shifts some of the counterparty risk from the issuer to the bearer.
Comment: The "counterparty risk" is one thing, but the mere *logistics* of tracking the bondholders and collecting from them WOULD be the ultimate nightmare! (grin)
Comment: True.  You know, I wouldn't mind finding a way to charge people interest for loaning *ME* money, though! (laugh)
Comment: @SRiverNet I agree but I guess that could be done electronically/centrally, if there were a use for it.
Answer: The rule is, no, negative coupons don't exist.
For the exception to the rule, Reuters found a couple of cases in history where bondholders paid a coupon:

PRACTICAL PROBLEMS
Data from IFR shows a range of issuers including
cities, banks and companies have bonds with theoretical negative
coupons.
These are unlikely to ever be imposed, though, as market
infrastructure is not set up to collect coupon payments from multiple
investors to an issuer.
Europe's main clearing houses, Euroclear and Clearstream, which settle
bond deals in the region, have said they will not accept any debt
which has a fixed negative interest rate.
On floating rate notes, they said negative coupons have usually paid
zero because the issuer set a floor, chose not to collect due to the
burden, or the bond terms did not allow for a payment to be made.
Matthew Hartley, a capital markets partner at lawyers Allen & Overy,
said bond terms would not normally allow cash to flow from investors
to an issuer.
"It is very difficult to enforce against what is in theory an
anonymous mass of bondholders," Hartley said.
This has still created uncertainty among investors though. Allen &
Overy said it has helped more issuers insert explicit terms in bond
documents flooring coupon rates at zero in recent years.
STRANGE EXCEPTIONS
There are some examples where negative coupons were
paid.
Euroclear said it has on a few occasions collected coupon payments due
from investors to issuers on short-term French commercial paper known
as titres de creances negociables (TCNs). This paper is usually only
held by a couple of investors so payments are easier to collect.
Going back 14 years, Warren Buffett's Berkshire Hathaway issued a bond
with an effective negative coupon in 2002. This was sold with a
warrant to buy Berkshire shares, the net effect of which was investors
paid more in interest than they received.
Comment: Maybe you could quote/summarize the main points of the article
Comment: At some point, the URL will be broken and this answer will be nearly useless.
Answer: Yes, but they're annuities, so they aren't "true" negative coupon bonds.
In August 2019 the 3rd biggest Danish bank Jyske Bank issued a series of 10 year mortgage bonds with a -0.5% coupon. This had to happen since fixed rate mortgage bonds have to be issued below par according to Danish law. But since the negative coupon is just subtracted from the principal payments, the payments are still going to the bondholders every quarter.
See the following article for more information: http://news.coveredbondreport.com/2019/08/annuity-structure-allows-jyske-negative-coupon-milestone/

Are negative coupon bonds possible?


tortoise svn checkout repository folder from Disk D:/ to Disk E :/ how to?

Question: I recently installed a tortoise svn subversion. Now, using tortoise svn, how can I check out the "Repository" folder from Disk D:/Repository  to Disk E:/ ?
Comment: re-tagged to remove PHP, MySQL and Zend Framework.
Comment: Are you asking to move your repo from D: to E: ? I think you can just move the folder the way you normally would.
Answer: The procedure for checking out a working copy from a local repository is described in detail here. If this specific section does not make sense, then you may want to read the entire containing chapter.


Xcode- store data in Core Data or SQLite?

Question: I am using Xcode 4.3-If I'm trying to store user's location (latitude and longitude) in a database and update their location to the database let's says every 30 meters they travel, would it be better to use core data or SQLite? Currently I am using core data and I'm having alot of trouble with it. I need to decide whether I need to make the switch and solely use SQLite. Any advice? *Note: The user does NOT need to see their own location data on the phone
Answer: Your "trouble" with core data suggests that you aren't very familiar with that API. On iOS, by default, core data uses sqlite as the underlying persistent store for it's data anyway, so in your case it's probaply not a matter of performance and nitty gritty stuff, but rather understanding the concepts. If you feel more comfortable and "at home" dealing with sqlite directly or using thirdparty sqlite objecitive-c wrapper frameworks, stick with that, get the job done. Out of the box, what core data gives you for free is a higher level of abstraction when dealing with data (it's all about objects and predicates, basically, and some helpers to bind data to your views) and memory management. The downside is, you have to teaxh yourself all that stuff, and it will crash on you all over the place if you get it wrong, so RTFM. Core Data: Once you have the expertise, it's heaven, but the way to expertise is a steep learning curve.
You want an advice to stick with direct sqlite access because you feel you can handle that? Go.
If you have time to teach yourself how Core Data works, why it's not a relational db etc, go, it's worth it and will make your developer's live much easier.
Answer: While they are both legitimate applications to what you are trying to do, the important difference between SQLite and CoreData is that SQLite can be relational.  If you need a relational table then I would say a switch can be rationalized, but if you have a simple denormalized data collection, you should be fine with CoreData. If anything setting up SQLite for your iOS application is relatively simple and worth a try.
More information can be found here: when-to-use-sqlite-instead-of-core-data-on-the-iphone/


Exporting a VM running as a Domain Controller

Question: There is a Microsoft KB article that talks about best practices for running a DC on a VM. One of the notes is "Do not use the Export feature on a virtual machine that is running a domain controller". In order to export a VM, the VM needs to be turned off. If you turn off a DC VM, export it, import it on another server and then power the VM back on, there should be no risk as long as the original (exported) VM is never powered back on. Can someone explain to me why this isn't supported? After doing some searching on Google, the sites I found just regurgitated this line from the KB article, but didn't offer any explanation as to why this isn't supported.
Answer: The core of the issue lies around the way each domain controller is uniquely identified by the domain, and how domain information is replicated through the system.
It's vital that:
A) Each domain controller retain its own unique ID, unchanged, at all times. Operations that clone a DC or alter its SID will break this.
B) New DCs are only added to the domain via the DCPROMO process. The domain depends on the information that this process adds into the domain, to identify a DC on the network. Any operation which brings a machine online which appears to be a valid DC, but has not been uniquely promoted in the domain, is going to cause all kinds of headaches.
C) A DC is never restored to a point backwards-in-time. So no snapshots etc. This is because the domain relies on an increasing ticket number type system to identify changes to the domain. A DC reverted to a previous state will have a lower ticket ID while the domain is on a higher ticket ID. this gets you into the USN rollback scenario that Grizly described.
So summary: Running virtual DCs is possible but you must take extra care not to perform VM operations which will violate DC operational requirements.
Comment: I don't see how there would be a USN rollback on a DC that's exported and imported. Exporting a VM doesn't change the SID, disk signatures, ect. Since the VM has to be turned off in order to export, there is no possibility of a USN rollback. This is why I'm trying to understand why this can't be done. Exporting a VM doesn't change anything because the VM setting are part of the export. If I were to just copy the VHD to another server and add it to Hyper-V, then the VM settings would be reset which could result in a USN rollback. But not when the VM is exported.
Comment: Good point. But then these are broad recommendations, and there are exceptions where you can perform some of the other 'dangerous' VM-related tasks on a DC without bad things happening. For example, reverting snapshots on a DC happens to work fine if it's the only DC in the domain. Perhaps it's just for brevity.
Answer: I think I found the KB you are referring to,http://technet.microsoft.com/sv-se/library/dd348452%28WS.10%29.aspx

All these recommendations are made to help avoid the possibility of an update sequence number (USN) rollback.

USN Info: http://technet.microsoft.com/sv-se/library/dd348479%28WS.10%29.aspx