Device Recommendation – Quit photography in 2006. Ready to restart. If you still have good lenses, you need advice on choosing the right body

I did safaris with a Canon EOS20D and a clutch with today's "L" lenses and not with "L II", e.g. "EF 24-70 mm f / 2.8 l USM" and "EF 70-200 mm f / 2.8 l IS USM". Had to stop, but kept all my equipment. Sure, I have to transform myself into a more advanced camera body. The Canon Mark 5D III model seems to be exactly what I want to come back to someday, and it seems to be something I hope to hold onto as a second body. I wonder if the first edition Canon L lenses will last in terms of quality. I was familiar with the limitations of IS in the L-Zoom models when I used them. I don't mind upgrading in the future, but assuming that my ultimate goal roughly corresponds to speculation about the possible release of a Canon 5D V later this year, it seems reasonable with Canon L IS lenses first edition to work for a while?

Reference request – Please advice in the master project in analytical number theory, since I have no other source of help and am stranded halfway

Please don't coordinate it. I have no other instructions.

I am a second year master student in mathematics in a third world country in Asia and have studied David M. Burton and Apostol's number theory in analytical number theory and modular functions as well as Dirichlet series in number theory. My institute, where I am doing my master's, did not have a professor who specialized in analytical number theory. At the end of the third semester, I asked a professor from other institutes for my master's thesis with the permission of a professor in my institute who specialized in combinatorial number theory. A professor from another institute in my country said yes to me and I visited the project in the 3rd week of January. She gave me a work by T Rivoal and W Zudilin, the title of which is "a note about odd zeta values". I had a question that I answered on this page. On February 17, I emailed her asking me how to do it and when to visit her institute. When she didn't answer, I emailed her again on February 29th. There were mid-day holidays that started on March 7th. I emailed her again on March 9 to ask when to visit her institute, but she didn't reply again. Then I start reading Zudilin's work "1 of odd Zeta values ​​from Zeta 5 to Zeta 25 is irrational by elementary means". Then I read articles by Kieth Ball and T rivoal "Infinite numbers of odd zeta values ​​are irrational". Then I send her an email again about what I'm studying and wonder what I should continue studying. I am sending this mail on March 20th. There was still no answer. The last email I sent was on April 2nd and still no response.

Now I'm in the middle of the project and have no instructions.

Therefore, I ask the researchers here to tell me about an open problem or research that I should continue to study.
I have completed one course on complex analysis, two courses on real analysis and one course on group rings and galois theory, topology (general) and other relevant courses besides the books I have studied in analytical number theory (mentioned above) and the articles have studied so far (mentioned above).

I will be really grateful for your advice.
I think the professor who agreed to lead me has no etiquette at all. She could have said no immediately if she didn't want to lead me the moment she decided to change her mind. The situation in my country is miraculously better with respect to Covid 19 than in other countries, and I am sure that it is not. I suffer because I have also contacted her doctoral student and her doctoral student said that she was on the Campus is in their office. However, when I asked her doctoral student to give me her contact number, the student angrily refused to do so without giving a reason. I also spoke to the professor who specializes in combinatorial number theory and he said that he should remove her name from the project and then start studying myself. (He is a really nice person, but can't help it because his specialization is different).

Can someone please help me with what I should continue to study in this project. I also filled out some application forms for European countries and the master project is really important, but she didn't even care and now I'm stranded in the middle without any help. Please guide me. I will be really grateful. I am very stressed and my career is in danger.

Please don't coordinate it. I have no other help.
I like the number theory in particular and the pure MathMaths in general very much.

Design Patterns – Need technical advice on routing data through UINavigationController

First of all a little introduction, I'm relatively new to Swift and programming in general, have been doing it since last year and love every new thing in this huge world.

My post is about some technical advice and knowing if the decisions made in my company make sense. I will first go over the proposed design and then my conclusions.

The design that is implemented;

We work in one big app. This app has several processes in which you follow a sequence of 5 to 8 controllers. Our team leader insists on this design pattern.
Let's call the first controller a holder, and the holder (black border) is responsible for a container. This container has a suitable navigation controller (red border). The owner also contains all the data (orange) that generate these secondary controllers.

Diagram of what this pattern wants to achieve

Diagram of what this pattern wants to achieve

Every Red Border Controller has a method for this:

private func getParent() -> HolderViewController? {

    if let parent = navigationController?.parent as? HolderViewController {

        return parent
    return nil

And to write in holder, we call the method;

getParent().someModel.someModelProperty = "some data”


The transfer of data by the navigation controller appears to violate the principle of individual responsibility.
Building strong references in each controller, even if I make sure the navigation controller is properly deinitized at the end of the flow, doesn't seem to be a good option. This can lead to memory leaks and maintain cycles.
I can't make sure that for some reason two controllers could try to access the same property at the same time.
This appears to be the singleton design pattern, but with a limited “scope”.


Since I am new and work in a company and every company has a hierarchy, my main goal is to find out whether my conclusions are wrong and to explain this better and more precisely.

To solve the memory leak problem, I first created a concurrentQueue.
Instead of directly accessing and writing to the model, I tried to address it using a method that uses a key path instead of the model directly. This is the method I use to write into the model.

In the owner:

class HolderViewController: UIViewController {

   @IBOutlet weak var bottomNavigationContainer: UIView!

   private var bottomNavigationController: UINavigationController!
   private var someModel: SomeModel!
   private let concurrentQueue: DispatchQueue = DispatchQueue(label: "concurrentQueue", attributes: .concurrent)

    override func viewDidLoad() {


    private func setupBottomNavigation() {

        rootController = SecondayViewController()

        if let root = rootController {

            bottomNavigationController = UINavigationController(rootViewController: root)
            bottomNavigationController.view.frame = bottomNavigationContainer.bounds

extension HolderViewController {

    public func setValueInModel(_ value: Value, forKey path: WritableKeyPath) {

       concurrentQueue.async(flags: .barrier) { (weak someModelInstance) in

            if var obj = someModelInstance {

                obj(keyPath: path) = value

    public func readFromHolder() -> SomeModel {

        concurrentQueue.sync {
            return self.someModelInstance

The controllers with a red border are located in the lower navigation controller.

class RedBorderViewController: UIViewController {

    var someString: String?

    @IBOutlet weak var textField: UITextField!

    override func viewDidLoad() {

    override func viewWillAppear(_ animated: Bool) {

      if let text = readFromHolder() {

        textField.text = text

    @IBAction func continueButton(_ sender: Any) {

      if let text = textField.text {


    private func getParent() -> HolderViewController? {

      if let parent = navigationController?.parent as? HolderViewController {

        return parent
      return nil

    private func setValueInHolder(string: String) {

      getParent().setValueInModel(string, forKey: .someModelProperty)


    private func readFromHolder() -> String {

       return getParent().readFromHolder().someModelProperty


The code above is just an example of how we do things

This looks like messy code to do an easy thing. We could use closures, delegates, segues, etc., but my team leader doesn't like the other, simpler, and more general solutions. I forgot to mention that each of our controllers has an xib and we don't use storyboards. I know the basics of using the other options. I try to understand whether this is a good solution or not and why and whether my way of thinking and my methods make sense.

Remember that any conclusion or solution that I implement can be wrong. So I share my thoughts with you to learn from your advice and experience

Thank you in advance. 🙂 🙂
Stay safe!

All advice on using the Internet service provider's modem / router combination with an Internet switch

I just bought an internet switch because I couldn't use ports on my own router (I'll add another PC later). Before I install everything, I want to ask you if this method that I want to use is correct?

    *Internet Switch model: TP-LINK TL-SG108PE
    *ASUS Router Model: ASUS RT-AX88U
    *ISP Router is connected with coaxial connection

Image from my_plan

I will be consulting your book and business 100 with high quality on a social website for $ 35

I will advise your book and business 100 with high quality on the social website

About this gig:
I will fully promote your website through 100 high quality social websites and SEO backlinks. High quality SEO backlinks are very important for a website for the top position from Google. This will help achieve organic traffic, rank, and more sales.

I will publish different sites like Facebook, Twitter, LinkedIn, Tumblr, Digo, Strumbleupon

blogger.wordpress, livejournal and many other etc sites.

  • Social bookmarking is a way for users to save, organize, search and manage websites. Users save links to websites they like or want to share and save those links on a social website.
  • Listing on a social bookmarking website can result in high quality traffic. Websites like offer the opportunity to bring a lot of new traffic to your website.
  • Search engines often list results from bookmark sites. So this is an additional way to appear in the search resultlts.

Gig feature:

  • Sites with high domain authority
  • All backlinks with anchor text.
  • Permanent links
  • I will provide a report in Excel format.

SQL Server – Quick Insertion from the Temporary Table to the Main Table – Advice Needed, Index Order Match?

I'm rewriting a C # console app from a single insert to do bulk inserts

Based on the advice given here, I need to mass insert it into a staging table (with ID identity seed).
Then I load into temporary tables, do a little processing and then paste them into the main table

This is possible around the clock in real time and must therefore be as quick and efficient as possible

1) What is the fastest way to insert data from the c # console app into the staging table (every 1 minute, approximately 50,000-150,000 records)? I am planning to use SqlBulkCopy

2) Does having an ID with identity seeds on the staging table slow things down? should i use a bunch?

3) My main question and the area with the highest risk is inserting it into the main occupancy table, so this has to be done as soon as possible to reduce the lockout: when I bulk insert into the main table, I should pre-order the data so that it can do the main cluster indexes match (in 3 columns: sensorId, DateTime, pkId) or do I only sort twice? This table is very busy.
Any other advice in this area is welcome.

This entire bulk insertion process is just a stored procedure, and I've been thinking about calling it every 1 minute from the SQL agent to make sure it's running (not sure if this is the best solution).

SQL Server 2017 ent.