Given a binary tree of leaves with weights, find minimum weights for internal nodes (such that…

So this is a question within a bigger question for which I’ve reduced to this so far:

If I have a tree (phylogenetic) with known weights for leaves, how would I find the weights for all internal nodes such that for every edge (u,v) in tree, the difference between their weights are minimized?

I.e. Given a tree T with n leaves each with a weight D1…Dn. Assign a weight Du to each internal node u = n+1,…,2n-1 such that Sum(u,v)∈E(T) is minimized.

If it helps, it might be similiar to the Sankoff algorithm or so. Thanks!

Why are my tomato plant leaves turning brown, shriveling, dying?

This has been progressive over the last 6 weeks, leaves turning dry, brown and getting very thin and shriveling like paper on a Tomato “Blue Berries” cherry tomato plant.

The closest I could guess was it was a fungus/disease of some sort after reading this article:

Tomato plant leaves do not begin by turning brown unless it’s a fungal
attack such as Septoria leaf spot or other fungal infections…

I bought a fungicide and have applied it once 10 days ago but as you can see still deteriorating, we’ve had 3 days of rain and I’m due to spray it again; am I on the right track? I’m really quite puzzled.

The plant receives a fortnightly dose of diluted Kelp Fertiliser and Liquid Potash.

It is now Spring here in Australia. If you need any more pics let me know.
Thank you!

The plant used to be in excellent health back in August:
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This evening:

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And these shots from October 1:

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Thanks fellow gardeners

Why does a lightsource postpone the time it takes for the leaves falling from a birch?

It is autumn and the leaves have already left their trees on all birch and other trees that has leaves, except one. This birch has a spotlight pointed to the tree and it is on 24/7. I have recognized that this birch have lost almost no leaves. And if we take a closer look at this birch, the back side of the birch, which is faced away from the spotlight have lost a noticeable amount more leaves than the front side which is directly hit by the light from the spotlight.

My conclusion is that having a lightsource pointing to a leafy tree will postpone the time from when it loses its leaves, relative to trees that does not have a lightsource pointerd at them.
But I have no idea why this is happening. I do not know anything about trees, leaves, chloryphyll or the reason why trees drops their leaves in the autumn.

If any one is a expert in this field and might know why this is happening, or just have a hypothesis of why this is happening please provide it since I find this really interesting and I can’t find anything on Google about this phenomenon.

You can make your anwer as complicated as you wish, I will understand it even if I might need to Google some of the things in the answer :).


Table shading in Word leaves text with unwanted white background

I am using Word 2016 on Windows 10. I cannot get rid of the white background for text when I apply shading to specific table cells, as you can see below:

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The shading is applied to the cell, but choosing any other value (text, paragraph, table) also results in the same behavior.

I am a seasoned Word user and this never used to happen before.

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How do I make a game object appear on the other side when it leaves the screen?

I’m doing an assignment for a course and what’s required is to include a moving asteroid in the game that starts moving in a random direction and when the asteroid leaves the bottom of the game window it should re-appear at the top of the game window
,so I wrote the script for warping and I applied it to the asteroid and a ship in my game ,then built it to WebGl game. the warping worked fine in the editor for both the ship and the asteroid, while it only worked for the ship in the built game, and I can’t figure out what’s wrong

this is the script

(ScreenUtils gives the borders of the screen)

float Radius;

void Start () {
    Radius = GetComponent().radius;
void OnBecameInvisible()
    // Make the ship wrap
    Vector3 position = transform.position;
    if (position.x - Radius >= ScreenUtils.ScreenRight || position.x + Radius <= ScreenUtils.ScreenLeft)
        position.x *= -1;

    if (position.y -Radius >= ScreenUtils.ScreenTop || position.y + Radius <= ScreenUtils.ScreenBottom)
        position.y *= -1;
    transform.position = position;

Why is the poem “Yggdrasil” placed where it is in House of Leaves, and which narrator included it?

At the very end of House of Leaves, there’s a page:

A scanned page, with the word

The word “Yggdrasil” doesn’t appear anywhere else in the book, and the index, which amusingly lists every word in the book and where it shows up (including some that don’t), confirms this.

I’ve got a lot of questions about this poem.

  1. Why does Danielewski bring this poem in quite suddenly on the last page of the book, without any clear callbacks to any other references in the book? As far as I’m aware, the notion of a world tree doesn’t appear anywhere else, and the book doesn’t contain clear allusions to Norse mythology as a whole.
  2. Which narrator in House of Leaves are we supposed to interpret as the one who decided to include this page? Is there anything to suggest which one of them it should be?
  3. The poem is supposed to be interpreted as physically looking like the worldtree itself: the “Ygg” and dot at the top are the canopy, “d/r/a/s/i/l” makes the trunk, the poem forms the base. But… what is the large “O” supposed to mean at the bottom of the poem?

Question: What happens when a teacher suddenly leaves work?

Is there a way a teacher could suddenly leave work without getting in trouble? Say a family emergency just happened, and the teacher needs to leave school immediately. How would they be able to get out without repercussions? What would happen to the rest of the class and how would this teacher be replaced? Do they have substitutes on standby for these kinds of incidents? Or is there another process to handle a teacher suddenly leaving work for the day?